Subjective and objective search for failures. Comparative characteristics of methods for direct assessment of technical condition. Subjective and objective methods of diagnosis. Braking properties and noise level in mechanisms

This problem is one of the central methodological problems of psychology. The cognitive situation in psychology is very difficult due to the fact that the subject of research has a complex system of determination, and the object of cognition is at the same time its subject. In addition, according to M. Bunge, one should distinguish between sciences, where the result is independent of the method, and science, where the result and operation with objects form an invariant:

"A fact is a function of the properties of an object and operations with it"
Druzhinin, 2002.

Psychology belongs to the sciences, where the fact is maximally dependent on the method of obtaining it. Therefore, the problem of creating an objective method becomes especially intractable.

The history of psychology can be viewed as a continuous history of the search for possible means of objectively studying psychic reality. At the same time, as noted by V.P. Zinchenko and M.K. Mamardashvili, various solutions to the problem fluctuated between two poles:

"... either the objectivity of the method is achieved at the cost of refusing to understand psychic reality, or the preservation of the psychic is achieved by abandoning the objectivity of analysis"

Due to the banal idea noted by the authors to place psychic reality in the brain space and “declare the brain as the subject of psychology” in psychology, “the term“ objective description ”is used as a synonym for the term“ physiological description ”, and“ psychological ”is used as a synonym for“ subjective ”.

For the first time, the problem of the objective method was posed in behaviorism(J. Watson, 1913). As you know, the only objective method of studying the psyche in behaviorism was observation and experiment, which made it possible to study psychic reality according to the "black box" principle. Understood in this way, the objective method was based on the rules of scientific observation that are characteristic of the classical ideal of scientific rationality (Mamardashvili, 1984). Moreover, the slogan of behaviorism: "Stop studying how a person thinks ..." meant a refusal to study the subjective world.

Behaviorism had a huge impact on the further search for an objective method. In 1900-1910. the first intellectual tests appear, and a little later - the classical theory of tests. Natural science concepts of the psyche, and in particular behaviorism, became the theoretical basis for them. Like the methods of scientific research in behaviorism, tests were created in accordance with the rules of the classical ideal of scientificity. Without diminishing the enormous importance of the test method, we can say that the requirements for the reliability and validity of the test are quantitative indicators of how close the methodology is to the ideal of absolute observation.

These principles have become the theoretical basis for more than just tests. Thus, A.G. Shmelev convincingly showed that questionnaires of personality traits are also based on a behaviorist interpretation of the concept of a personality trait (see: Shmelev, 2002, pp. 51-52). Finally, the whole theory of psychological experiment, and in particular the idea of ​​an ideal experiment, or an experiment of complete correspondence, which has developed in psychology (Gottsdanker, 1982), is an attempt to make an experiment a method with the qualities of the Absolute observer. We can say that all nomothetic research methods were created in psychology based on the classical ideal of scientific rationality.

At the same time, methods were created in psychology, which were based on completely different initial philosophical and worldview preconditions. Such are, for example, psychoanalytic therapy as a method of practical psychology and projective techniques, most of which are based on psychoanalytic theory - suffice it to recall Jung's associative test, the Rorschach technique or the thematic apperception test. They were quite consistent with the non-classical ideal of rationality. However, this was achieved due to the fact that in working with such methods, it is almost inevitable that the researcher or practitioner introduces his subjective world into the understanding of the psychic reality of another person. Until now, in the English-language literature, one can find the opposition of objective and projective methods.

Psychologists have tried to overcome these extremes in different ways. So, for example, at the end of the 30s. various psychological theories are created that represent a compromise between psychoanalysis and behaviorism (for example, the well-known theory of frustration - aggression by N. Miller and J. Dollar). These theories were created not only as a search for the "golden mean" between the psychological theories prevailing at that time in the United States. They were created as a theoretical basis for a method that would allow the study of the psychological reality of a person, while remaining as objective as possible. In this vein, studies were carried out by L. Abt, D. Rapoport, S. Rosenzweig and many other representatives of projective psychology of that time. Almost all of them set themselves the task of creating such a system of criteria for processing and interpreting projective methods so that the result, as far as possible, would not depend on the subjectivity of the researcher. But, as noted by N. S. Burlakova and V. I. Oleshkevich (2001), despite the fact that the number of formalized criteria increased incredibly, the data obtained often remained vague and difficult to connect with each other:

“Due to the desire to conform to scientific standards (that is, traditional, classical ideals of scientificity), the focus on the study of the unique, singular (which expressed some general tendency present in the humanities) was increasingly transformed into a line of study of deviations from the average individual (from" stamped "content, from" cliché plots ", etc.)"
Burlakova, 2001.S. 12.

The given plot from the history of psychodiagnostics reflects some general features of the search for an objective method in psychology. The situation in which psychology found itself in this search became the subject of methodological analysis. This is how the concept of nomothetic and ideographic approaches and the relationship between them, formulated by G. Allport, appeared. As already mentioned, psychosemantic methods became one of the attempts to overcome the extremes of nomothetic and ideographic approaches. Started back in the 1950s, studies of human subjective semantics are still being successfully pursued, including in contemporary Russian psychology (Petrenko, 1997; Shmelev, 2002). The problem of creating an objective method has been and remains one of the most urgent in Russian psychology. Let us recall the most significant achievements made in the search for an objective method.

First of all, such achievements should include the method of natural experiment proposed by A.F. Lazursky. According to AF Lazursky, a natural experiment was a means of overcoming the shortcomings of a laboratory experiment and at the same time made it possible to implement a scientific approach to the study of the psyche.

In the first post-October years, Russian psychology experienced the strongest influence of Marxism, which became the state ideology. In these conditions, new directions of psychology developed, the purpose of which was an objective study of the psyche. These included KN Kornilov's reactology and VM Bekhterev's reflexology. The method of reflexological research was analyzed by LS Vygotsky in his first work on psychology (1982, vol. 1). As noted, one of the key ideas of the work is the need to take into account the subject's subjective reality in reflexological research. According to Vygotsky, only in this way is it possible to overcome the idealistic separation of the psyche from the brain and create a truly objective method of psychology. These ideas were further developed in the works of L. S. Vygotsky, in which the problems of psychodiagnostics were considered. The result of the search for Vygotsky was the creation by him of a method of a formative experiment, or an instrumental method, as he himself called it. First of all, the instrumental method is a means of studying human psychological tools, the existence of which is an axiom for Vygotsky. A person uses psychological tools to master his behavior, and mastering them "re-creates the function and raises it to a new level" (Vygotsky, 1982, vol. 2). The objectivity of the method is achieved due to the fact that it allows you to study the process of re-creating psychological reality when a person masters tools (for example, when teaching and upbringing).

In later years, in Russian psychology, several directions emerged in which this problem was solved. One of them is the further development of the experimental formative method of L. S. Vygotsky. The method of the formative experiment was developed in pedagogical psychology (the method of developing education by D. B. Elkonin and V. V. Davydov), in developmental psychology (the method of stage-by-stage (planned) formation of mental actions and concepts of P. Ya. Galperin). Another line in the development of the objective method of psychology was outlined by A.R. Luria in the study of the dynamic localization of mental processes.

V. P. Zinchenko and M. K. Mamardashvili deeply analyzed the problem of the objective method in psychology. Analysis of the problem required reflection on the philosophical premises used to create an objective method. The initial philosophical premises are a number of provisions that were subsequently developed by V.P. Zinchenko and M.K. Mamardashvili in their later works:

1. indivisibility of the phenomena of psychological reality into elements;
2. the need to revise the traditionally sharp opposition of material and ideal, external and internal, objective and subjective;
3. introducing internal (psychological) reality into the object of study: “... acceptance of the fact that subjectivity itself enters the objective reality given to science is an element of its definition, and is not located above it as a dissolved phantom of physical events ... or behind her in the form of a mysterious soul ”;
4. consideration of consciousness as a psychological reality, located in the gap of continuing experience, allowing to postpone action and representing a space where "... symbolizing material transformations of objective circumstances invade, giving at the same time completely bodily, and not subjectively acting formations, deployed outside of introspective reality";
5. consideration of psychic reality as a special field, non-Euclidean in its spatial characteristics, in which both the objective content of external objects and the very subject of cognition, communication and action are presented.

Only after such a revision of the initial philosophical premises is it possible to create an objective method. As one of the possible ways, the authors call the creation of visual structural and functional models of mental "reality, which are" both a visible thing and an understanding. " -functional models of action (for example, Gordeeva, 1982) The technique of microstructural analysis of actions made it possible to reconstruct its structure.

The outlined approach is implemented in personality psychology and psychosemantics, albeit in a slightly different way. The parameters of the semantic field or personality factors are dimensions of a person's subjective reality. However, personality psychology proceeds from the fundamental possibility of their objectification using psychometric methods, subjective scaling procedures, and ranking lists of values. Naturally, personal factors or parameters of a person's semantic space are not thought of as spatial in the everyday sense and not as spatially localized in the cerebral cortex.

Some research in the field of projective psychology is also aimed at finding an objective method in the field of psychodiagnostics, which has traditionally been opposed to objective methods. So, N. S. Burlakova and V. I. Oleshkevich (2001), relying on the ideas of M. M. Bakhtin as a general scientific methodology and on the cultural-historical theory of L. S. Vygotsky as a specific scientific methodology, consider the projective method as a means externalization of the internal dialogue of a person. The psychodiagnostician in this situation is assigned the role of a mediator (mediator), who contributes to the objectification of the internal dialogue with the help of an external means (projective technique).

The examples given by us do not exhaust the whole variety of approaches to the creation of an objective method in psychology. Attempts to create an objective method go both along the line of developing new procedures and research techniques, and along the line of rethinking already known research methods. However, most of these attempts have something in common. This is a rejection of the traditional dualistic oppositions of objective and subjective, external and internal, material and ideal.

Whatever the refusal of a job, even for seasoned candidates, it sometimes causes pessimism. But do you always have to scold yourself for your mistakes?

Have you ever gotten rejected while looking for your dream job?

"Why was I refused?" - some applicants are tormented, going over in memory every moment of the interview and every phrase in the resume. Such reflection, of course, is useful: you can really understand what confused the recruiter in your candidacy. But it's not always about you. Experts admit that there can be a lot of reasons for refusing to hire, and they are not always associated with the low professionalism of the candidate. It's no secret that job seekers are also rejected because they are too good.

So, let's consider why you could be refused. There can be a lot of reasons, so we divided them into two parts - objective (you really behaved incorrectly, made mistakes or did not fit for serious reasons) and subjective (you were not taken due to certain circumstances in the company or because of not quite correct recruiter estimates).

Objective reasons

• 1 Your candidacy does not meet the requirements of the vacancy. For example, the ad says that a higher technical education is required, but you do not have it or it has not yet been completed. Or they are looking for a specialist with many years of work experience for a certain vacancy, and you have not yet had time to acquire one. Such restrictions can be attributed to discrimination, but it is better to find out all the requirements before the interview in order to avoid misunderstanding during the conversation with the recruiter.
• 2Resume for some reason stands out too much from the crowd, and the recruiter finds ways to stand out inappropriate. For example, a candidate makes a lot of and not always good jokes in his CV (for example, he said about himself: “I studied something and somehow”; “I am looking for a job of a spider-man”, etc.). Or, for some reason, he marked information about each place of his work with different colors - blue, pink, yellow. Or even abandoned the business style of presentation in favor of some kind of "creative".
• 3At the interview, the HR manager found the candidate's appearance to be inconsistent with the corporate culture of the company. For example, everyone goes to work in business suits, and the applicant shows up in frayed jeans. Or with too bright manicure (in a too short skirt, with massive earrings, in dirty shoes, etc.).
• 4In the course of the interview, it became apparent that the candidate had lied in his resume or over-embellished his experience and education. No comment: you can't make a career out of deception.
• 5In the course of the interview, the applicant did not demonstrate his motivation and interest in this particular job in this company. The position “persuade me, and maybe then I will agree to your boring job for little money” is inappropriate in most cases. If the vacancy is not interesting - do not submit your resume.
• 6In the interview, the applicant asked too many questions about vacation and salary and too few about responsibilities and work rules.
• 7 Illegal speech of the candidate, especially if he is applying for a position where constant communication with clients, partners, etc. is expected.
• 8 Uncertainty, tightness of the applicant or, on the contrary, his excessive relaxedness and self-confidence.
• 9During the interview, the applicant was critical of his former boss, company, colleagues. Such a candidate may be considered a conflict or, even worse, a scandalous person.
• 10The applicant expressed doubts about the qualifications of the HR manager. "How can this girl evaluate me, an experienced specialist?" - Recruiters are often faced with this position, especially among older applicants. Remember: The HR manager evaluates the baseline suitability of your resume and your overall adequacy. Professional qualities are assessed by a potential manager if you pass the selection from an HR manager.
• 11 Alas, this is reality: the candidate may be too young or too “old” for a particular job. Most likely, this reason will not be announced to you, but the age limit is common for many companies.
• 12The candidate did not show himself to be a polite person: he didn’t say hello (or didn’t say hello enough), didn’t let the girl in the doorway, didn’t say “all the best” at parting, etc.
• 13 The applicant tried to flirt with the recruiter.
• 14 During the interview, the candidate's phone rang. The fact that he didn’t turn it off during the interview is not good in itself. But the fact that he decided to answer the call can put an end to employment in this company.

Subjective reasons

Now let's look at the subjective reasons for a possible refusal - those because of which you should not worry too much, because you were refused at all because you are not qualified enough or do not have business etiquette. And why?

• 1Resume seems to the recruiter too good - there is an obvious overqualified, that is, excessively high qualifications of the applicant for this vacancy. It is believed that a “too smart” candidate is far from the best option for filling a vacancy, especially if it does not imply career growth. There are several drawbacks: a specialist can quickly get bored of the lack of interesting tasks, lose motivation and even leave the company, and besides, he needs to pay more.
• 2Another scenario from point 14: during the interview, the candidate's phone rang. The applicant dropped the call, but a recruiter with a delicate aesthetic taste has a complete rejection of the song set as a call (for example, "Vladimirsky Central"). Or any other melody - the concept of "delicate taste" is known to be stretchable.
• 3 The candidate does not look like a real team player in the eyes of the recruiter - as it seems to the HR manager, he has too much individualistic principle.
• At the same time, the company may have rather specific wishes for the appearance of the future employee. This is especially true for specialists who work with clients or, to one degree or another, are the "face of the company" - secretaries, PR-managers, etc. Is it worth reproaching yourself for the fact that you were born, for example, not a blonde with legs from the ears, but a brown-haired woman of ordinary build?
• 5During the interview, the applicant told a joke that the recruiter did not like.
• 6 Too high competition for this job. You can perfectly match the vacancy, but three or four more candidates will also perfectly match it ...
• The 7HR manager, for some reason, decided that you would not fit into the existing team. For example, everyone in the department loves corporate parties, and you said that you are not a "party" person. Or all the staff are vegetarians and you asked if there is a café nearby with good meat dishes.
• 8Finally, the recruiter or potential boss might just humanly dislike the job seeker. Too strong smell of perfume, too loud or, on the contrary, very quiet voice, inappropriately expensive handbag - there can be a lot of subjective factors.

The list goes on. As you can see, the reasons for refusing employment are very different, and not always the applicant should blame himself for any mistakes. Recruiters are people too, and they can make mistakes, like any specialists. Do not take too strict an assessment to heart, be sure: the main thing is your professional qualities, and if you were refused, then perhaps the missed vacancy was simply “not yours” and everything that happened will ultimately only benefit your career. ...

L-6. Flaw detection methods. Non-destructive testing by magnetic method.

Methods for assessing the condition of machinery and equipment

Types of defects and their technical diagnostics

Defect is each individual non-compliance of the object with the established requirements.

Defects vary in

Sizes;

Location;

By nature;

Origin.

Defects can form in the process

Melting and casting (shells, pores, looseness, inclusions, etc.);

Pressure treatments (inner and outer cracks, flaws, delamination, sunsets, etc.);

Chemical and chemical-thermal treatment (zones of coarse-grained structure, overheating, burn-out, thermal cracks, unequal thickness of the thermal layer, etc.);

Mechanical processing (grinding cracks, non-compliance with dimensions, risks, etc.);

Welding (lack of penetration, slag inclusions, gas pores, etc.)

The size or scale of the defect- a quantitative characteristic of the deviation of the actual dimensions and (or) the shape of parts and their surfaces from the nominal values.

Diagnosis- determination of the technical condition by indirect parameters and signs.

Technical diagnostics- a branch of knowledge that studies the technical condition of objects to be diagnosed and the manifestation of technical conditions, develops methods and means for their detection and localization of defects in technical systems, as well as the principles of organizing and using diagnostic systems.

The task of diagnostics is a preventive examination of the machine as a whole or its component parts, mainly without disassembly; determination of the technical condition of mechanisms, checking their operability, prompt detection of malfunctions; determination and prediction of possible deviations in operating modes; collection of initial data for predicting the residual life and reliability of components.

Distinguish between subjective and objective search for failures and malfunctions.

Subjective search is a qualitative assessment based on the experience and skills of the performer.

Objective method - the establishment of quantitative estimates based on instrumentation, stands, special tools.

In turn, control methods can be divided into

Direct - reliable functional connections between the controlled and measured parameters are used (visual control methods);

Indirect - flaw detection. It is used to detect hidden internal defects without destroying parts (non-destructive testing).

Fault detection is aimed primarily at identifying defects in compressor parts and their assemblies.

A characteristic sign of flaw detection is the receipt of flaw detection information based on the use of non-destructive methods for monitoring certain parameters of the state of parts and assemblies. At nodal fault detection reveals deviations of parts of units from a given relative position. At detailed fault detection determine the reusability of parts and the nature of the required repairs. Parts are sorted into the following groups:

parts with wear within tolerance and suitable for reuse without repair;

parts with higher than permissible wear, but suitable for repair;

parts with wear above the permissible level and unsuitable for repair.

The main methods of flaw detection of compressor parts and assemblies are shown in Fig. eleven.

Visual inspection (external examination) reveals visible cracks, breaks, bends, abrasion, chipping, crushing, corrosion, scratches on the surfaces of parts.

For visual control of the state of parts without disassembly, devices are used to control internal surfaces and detect defects in hard-to-reach places - endoscopes and borescopes.

The principle of operation of endoscopes is to examine an object using a special optical system that transmits an image over considerable distances (up to several meters). In this case, the ratio of the length of the endoscope to its cross-section is much greater than unity. Exists lens, fiber optic and combined endoscopes. For visual observation, the compressor design must have appropriate cavities, hatches, etc.

With the help of lens endoscopes, cracks, scratches, corrosion spots, gouges and other defects with dimensions of 0.03-0.08 mm are detected. Lens endoscopes are usually a rigid structure, however, devices (having sections of the body with a flexible sheath) have been created that bend within the range of 5-10 °. The diameter of the field of view is 3-20 mm.

Flexible fiber-optic endoscopes allow transmitting an image of the controlled object along a curved channel. A schematic diagram of such control is shown in Fig. 12.

A touch test is carried out to detect changes in the geometric parameters of parts due to wear, as well as to identify violations of the operating mode of parts that are part of friction pairs.

Instrumental methods for determining the wear of parts are given in table. eight.

Measurement with the help of a measuring tool, as a rule, the visual inspection of the parts is completed. Measurements allow determine the wear of certain working surfaces, the deviation of the elements of the part from the correct geometric shape as in the longitudinal one (taper, barrel, etc.), and in pepper (ovality, cut, etc.) sections of the part. When measuring parts, a standard universal measuring tool is used (calipers, micrometers, internal micrometers, etc.).

The deviation of the shape of parts such as bodies of revolution in cross-sections is determined using circular meters (for example, mod. 256, 289, 290). When performing fault detection of parts in a specialized repair enterprise, visual-optical devices (projectors), devices for automatic control of linear dimensions, etc. are used to control dimensions. The measurement method is most often used when determining defects in cylinders, cylinder bushings, pistons, piston rings , piston rods and pins, crankshafts, rotors, main and connecting rod bearings, crossheads and parallels.

The weighing method is usually used to determine the amount of wear and the rate of wear of parts during compressor life studies (life tests). The application of this method in production conditions is complicated by the lack of definiteness of the place of wear, as well as the absence of strict dependences of wear, expressed through a change in the size of the wearing surface, on the change in the mass of the part. Therefore, in production conditions, the method is used for a qualitative assessment of the state of the part during defect detection.

The method of artificial bases allows you to determine the local wear of the part with high accuracy. The essence of the method: before starting operation, holes are made on the wearable surface (Fig. 13, a), or square prints (Fig. 13, 6). Imprints can be obtained, for example, by pressing a diamond pyramid. The geometric parameters of the holes and indentations are measured before and after the operation of the part.

The disadvantage of this method is the need to damage the investigated surfaces, which in some cases can lead to a distortion of the wear pattern.

Profiling is a graphical recording of a profile.

With the surface activation method, the inspected surface (area, point) of the parts is pre-irradiated with a stream of alpha particles. As a result, a mixture of radioactive isotopes is formed in the microvolume, which emits gamma radiation. As the activated volume wears out, the radiation activity decreases, recorded by radiometric equipment (fig. 14).

Defect detection of parts based on geometric features (wear, deformation, roughness, etc.) constitutes important information about the technical condition of the inspected objects. but to assess the resource parameters, information is also required on the internal state of the material of the parts, which determines their static and dynamic strength.

Brief characteristics of the main methods for detecting defects in the material of compressor parts are given in table. nine.

The purpose of hydro-pneumatic tests is to identify the tightness of the assembly, welding, etc., as well as to test the strength of the products themselves.

When carrying out hydro-pneumatic tests, the products are subjected to the action of increased pressure, withstand a certain time. For example, a crankcase assembly with covers is tested for strength by hydraulic pressure, as a rule, 3.5 MPa with holding, under pressure for 10 minutes. During testing, personnel should be behind an impervious partition. It is allowed to approach the product for inspection only after holding the tested crankcase under pressure. If, when inspecting the crankcase under fluid pressure, leaks, dew formation, sweating, etc. are observed, then the crankcase is rejected.

The pressure is gradually raised to 2.1-2.5 MPa. The crankcase is kept under pressure for at least 5 minutes. At the same time, the appearance of air bubbles in the water is controlled.

Bubbles appear in places of leaks, which are marked by the tester.

After testing, the crankcase and other parts are carefully inspected. Suitable parts are branded.

The goals of hydro-pneumatic tests carried out during the defect detection of compressor parts coincide with the goals of similar tests carried out when diagnosing compressors as a whole.

Housings, crankcases, cylinders, cylinder liners, fittings, pipelines, etc. are subjected to hydro-pneumatic tests.

Compressor casings (PC block crankcases) under operating conditions are under pressure of water and gas (air or refrigerant vapors) and their insufficient strength can lead to an accident, and insufficient density can lead to gas leakage.

Block crankcases are tested for strength with water under pressure, and for density - with air under pressure.

The crankcase assembly with covers is tested for strength by hydraulic pressure, as a rule, 3.5 MPa with holding, under pressure for 10 minutes. During testing, personnel should be behind an impervious partition. It is allowed to approach the product for inspection only after holding the tested crankcase under pressure. If, when inspecting the crankcase under fluid pressure, leaks, dew formation, sweating, etc. are observed, then the crankcase is rejected.

After the pressure is released to zero, the water is drained from the crankcase.

When testing the crankcase for tightness, a hose of the air network is connected to it, after which it is lowered into a bath with water using a hoist. The thickness of the water layer in the bath above the submerged crankcase is usually 300-500

The pressure is gradually raised to 2.1-2.5 MPa. The crankcase is kept under pressure for at least 5 minutes. At the same time, the appearance of air bubbles in the water is controlled.

Bubbles appear in places of leaks, which are marked by the tester.

After testing, the crankcase and other parts are carefully inspected. Suitable parts are branded.

At a number of factories, when testing block crankcases for density, their outer surfaces are coated with a soapy solution, to which a few drops of glycerin are added to prevent drying out. The test also monitors the appearance of bubbles.

Preparation for hydro-pneumatic testing of freon compressor parts is carried out especially carefully. Parts are cleaned by blowing dry compressed air, Parts in contact with freon are degreased, for example, in carbon tetrachloride or solvent gasoline (white spirit). The strength and density test is carried out under water using dry air or nitrogen.

Non-destructive testing by magnetic method.The magnetic particle method is designed to detect surface discontinuities in the metal (cracks, sunsets, inclusions, delamination, etc.) by detecting stray magnetic fields that arise near defects after magnetization of the test objects.

Using magnetic methods, cracks, surface films, hairs and other defects in steel and cast iron parts of compressors: crankshafts, connecting rods, rod, etc. are detected.

With the magnetic particle method to identify discontinuities in products, magnetic powders (luminescent, colored) or magnetic suspensions are used as indicators. According to GOST 21105-87, the highest sensitivity of the method is limited by defects with an opening width of 10 microns and a minimum length of a conventional defect of 0.5 mm.

The magnetic particle inspection method consists of the following operations:

preparation of a part for inspection,

magnetization of the part,

applying a magnetic powder or suspension to a part,

inspection of the part,

assessment of control results

demagnetization.

Preparation for inspection consists in cleaning the surface of the part from rust, scale, oil contamination. The roughness of the cleaned surface of the control zone should be no more than 40 micrometers.

Materials used: detergents, solvents (gasoline, kerosene, acetone), SD-1, AFT-1, hair brushes, brushes, fine sandpaper, scrapers, files, cotton lint-free rags, white contrast paint such as ELYWCP-712 or similar (applied to increase contrast with a thickness of 5-10 micrometers).

If the surface of the part is dark and the black magnetic powder is poorly visible, then it is sometimes covered with a thin layer of white paint (nitro-lacquer).

The sensitivity and the possibility of detecting defects depend on the correct choice of the method, direction and type of magnetization.

Direct current is most convenient for detecting internal defects (at a distance from the surface up to 3 mm). However, parts with a wall thickness of more than 25 mm should not be magnetized with direct current, since after testing it is impossible to demagnetize them. Internal defects can be detected using alternating (and pulsed) currents, if its amplitude is increased by 1.5-2.5 times in comparison with the current amplitude calculated to detect surface defects. Magnetization is carried out in different ways: by passing a current through a part or a rod passing through a hole in the part; with the help of several turns of wire passing into the hole of the part and covering the part with a part of the turn from the outside. Longitudinal magnetization is more often carried out with the help of a solenoid and less often with the help of electromagnets (even less often, permanent magnets are used).

In the defect zone, the parameters of the stray magnetic field change sharply. The lines of force in the magnetized part go around the defect as an obstacle with low magnetic permeability. To detect a defect in a part, a perpendicular position of the defect in the direction of the magnetic field is required. The part must be checked in two mutually perpendicular directions.

Magnetic powder is prepared from dry, finely ground red lead or from pure iron oxide, ground in a ball mill and sieved. The powder is applied to the part by spraying (dry magnetic powder method) or by immersing the part in a container with powder, as well as by air suspension.

Water, kerosene, oil magnetic suspensions are used.

To obtain 1 liter of an aqueous suspension, 15-20 g of oleic or laundry soap are diluted in a small amount of warm

water, then add 50-60 g of magnetic powder and the resulting mixture is thoroughly ground in a mortar. Then add hot water to 1 liter.

Oil suspensions are obtained on the basis of, for example, PM oil or transformer oil.

The sensitivity of magnetic powders and suspensions is assessed using the MP-10 device or the U-2498-78 unit.

The magnetic suspension is applied to the part by immersion in a bath, by irrigation, and also by aerosol. The pressure of the jet must be weak so that the powder is not washed off from defective places.

The inspector should inspect the part after draining from the bulk of the suspension, when the picture of the powder deposits remains unchanged.

Details are checked visually, but in doubtful cases, optical instruments are used to decipher the nature of the defects. The magnification of the optical means should not exceed x10. Portable and mobile magnetic flaw detectors are used.

An experienced inspector carries out the sorting of parts according to the results of the control. At his workplace, there should be photographs of defects or their defectograms (replicas with powder deposits, taken from defective places using adhesive tape), as well as control samples with a minimum size of unacceptable defects.

Powder deposits on hairline look like straight or slightly curved thin lines. Deposition of powder over cracks has the form of clear broken lines with dense deposition of powder. Powder rolls deposited under flockens, represent clear and sharp short lines, sometimes curved, located in groups (less often single). Zakovs give a clear deposition of powder in the form of smoothly curved lines. Pores and other point defects appear in the form of short strips of powder, the direction of which is perpendicular to the direction of magnetization.

The main disadvantage of the magnetic particle method is the possibility of rejection due to powder deposits on the so-called false defects (magnetic inhomogeneity, hardening of copper).

The fluxgate method is used for semi-automatic quality control of the surface and welded joints of thick-walled ferromagnetic products such as shells, sleeves, housings for defects (multidirectional cracks, lack of penetration, pits, etc.) on the surface and at a depth of up to 5 mm. The "Radian-1M" fluxgate installation allows detecting defects with dimensions of at least 0.15 mm in depth and 2 mm in length.

Magnetographic flaw detectors make it possible to reproduce the recording of defect fields on magnetic tape. The main element in the magnetographic method - magnetic tape - performs a double role: first it serves as an indicator of a defect, and then becomes a source of a secondary imaged magnetic field, which in turn is read by another indicator. Magnetographic control method consists of recording and reading processes. Provides stable detection of defects up to 2 mm in diameter at a depth of 20 mm.

Threats as possible dangers of committing any action directed against the object of protection, manifest not by themselves, but through vulnerabilities (reasons) leading to a breach of information security at a specific informatization object. Vulnerabilities are inherent in the object of informatization, are inseparable from it and are caused by the shortcomings of the functioning process, properties of the architecture of automated systems, exchange protocols and interfaces used by the software and hardware platform, operating conditions and location. Each MB threat mapped various vulnerabilities ... Elimination or significant mitigation of vulnerabilities affects the ability to implement threats to information security.

For ease of analysis, vulnerabilities are divided into classes according to belonging to the source of vulnerabilities, classes of vulnerabilities are divided into groups by manifestations:

1.Objective Vulnerabilities (Associated with technical means of radiation, Activated, Determined by the features of the elements, Determined by the features of the object of informatization)

2.Subjective vulnerabilities (Errors (negligence), Violations, Psychogenic)

3.Random vulnerabilities (Crashes and failures, Indirect causes)

Objective vulnerabilities... Objective vulnerabilities depends on construction features and technical equipment characteristics used at the protected object. Complete elimination of these vulnerabilities is impossible, but they can be significantly weakened by technical and engineering methods of countering threats to information security. These include:

1)accompanying technical means radiation :

a) electromagnetic (spurious emissions of elements of technical equipment, cable lines of technical equipment, radiation at the frequencies of the generators, at the frequencies of self-excitation of amplifiers);

b) electrical (pickup of electromagnetic radiation on lines and conductors, leakage of signals in the power supply circuit, in the ground circuit, uneven consumption of the power supply current);

v) sound (acoustic, vibroacoustic);

2)revitalized :

a) hardware bookmarks (installed in telephone lines, in the power supply network, in rooms, in technical equipment);

b) software bookmarks (malicious programs, technological exits from programs, illegal copies of software);

3) determined features of the elements :

a) elements with electroacoustic transformations (telephones, loudspeakers and microphones, inductors, chokes, transformers, etc.);

b) elements subject to exposure to electromagnetic fields (magnetic carriers, microcircuits, nonlinear elements, defeated by HF imposition);

4)determined by the characteristics of the protected object :

a) location object (lack of a controlled area, the presence of direct visibility of objects, remote and mobile elements of the object, vibrating reflective surfaces);

b) organizing channels of information exchange (use of radio channels, global information networks, leased channels).

Subjective vulnerabilities... Subjective vulnerabilities depend on the actions of employees and, basically, they are eliminated by organizational and hardware-software methods of countering threats:

1) Errors :

a) at preparation and use of software (when developing algorithms and software, installing and downloading software, operating software, entering data);

b) at management of complex systems (when using the capabilities of self-learning systems, setting up services for universal systems, organizing information exchange flow control);

c) at (when turning on / off technical means, using technical means of protection, using means of information exchange).

2) Violations :

a) regime protection and protection (access to the facility, access to technical equipment);

b) regime operation of technical means (energy supply, life support);

c) regime use of information (processing and exchange of information, storage and destruction of information carriers, disposal of industrial waste and rejects);

d) regime confidentiality (by employees outside working hours, laid off employees).

Random vulnerabilities depend on the characteristics of the environment surrounding the protected object and unforeseen circumstances. These factors, as a rule, are not very predictable and their elimination is possible only when carrying out a complex of organizational and engineering-technical measures to counter IS threats:

Crashes and failures :

a) failures and malfunctions technical means (processing information, ensuring the operability of information processing facilities, providing security and access control);

b) aging and demagnetization of carriers information (floppy disks and removable media, hard disks, microcircuit elements, cables and connecting lines);

v) software crashes (operating systems and DBMS, application programs, service programs, anti-virus programs);

d) failures power supply (information processing equipment, support and auxiliary equipment).

Methods for diagnosing vehicles are divided into subjective and objective. The subjective methods are based on the methods of determining the technical condition of the vehicle by the output parameters of dynamic processes. However, obtaining, analyzing information, as well as making a decision on the technical condition are carried out with the help of human senses, which, of course, has a fairly high error.

Subjective methods

The most widespread are the following subjective methods:

• visual
• listening to the operation of the mechanism
• feeling the mechanism
• conclusion on the technical condition based on logical thinking

The visual method makes it possible to detect, for example, the following malfunctions:

• violation of seals, cracks, defects in pipelines, connecting hoses, etc. - leakage of fuel, oil, operating fluids
• incomplete combustion of fuel - by smoke from the exhaust pipe
• leakage of injectors - by increasing the oil level in the engine sump, etc.

Listening to the operation of the mechanism allows you to detect the following malfunctions:

• increased clearance between valves and rocker arms of the gas distribution mechanism - by knocking in the area of ​​the valve mechanism
• increased wear of connecting rod and main bearings - by knocking in the corresponding zones of the crank mechanism when changing the crankshaft speed
• excessive advance or lag of fuel injection - by the nature of the exhaust sound (with early injection - "hard work", with late - "soft")
• car clutch malfunctions - noise and knocking when shifting gears, etc.

By the method of feeling the mechanism, you can determine the following malfunctions:

• loosening of fasteners - according to the relative movement of parts
• malfunctions of individual rubbing mechanisms and parts - due to their excessive heating
• malfunctions of the steering mechanism - by jolts on the steering wheel, etc.

Based on logical thinking, a conclusion can be made about the following malfunctions:

• fuel equipment - difficult to start the engine
• cooling systems - the engine is overheating, etc.

Objective methods

Objective methods are based on the measurement and analysis of information about the actual technical condition of the elements of the car with the help of control and diagnostic tools and by making decisions on specially developed diagnostic algorithms. The use of certain methods depends significantly on the goals that are solved in the process of technical preparation of cars. However, due to the increasing complexity of the vehicle design, increased requirements for performance, and the intensity of use, objective diagnostic methods are increasingly being used.

Methods for diagnosing cars, their units and assemblies are characterized by the method of measurement and the physical essence of the diagnostic parameters that are most suitable for use, depending on the problem of diagnosis and the depth of diagnosis.

Currently, it is customary to distinguish three main groups of methods, classified by the type of diagnostic parameters.

Group I methods are based mainly on the imitation of the high-speed and load modes of the car and the determination of the output parameters under the given conditions. For these purposes, stands with running drums are used or the parameters are determined directly during the operation of the car on the line. Diagnostic methods based on performance parameters provide general information about the technical condition of the vehicle. They allow you to assess the main performance of the vehicle:

• brake
• capacity
• fuel efficiency
• stability and controllability
• reliability
• ease of use
• etc.

Group II methods are based on an objective assessment of geometric parameters in statics and are based on measuring the values ​​of these parameters or clearances that determine the relative position of parts and mechanisms. Such a diagnosis is carried out in the case when these parameters can be measured without disassembling the mates of the rubbing parts. Structural parameters can be clearances in bearing assemblies, valve mechanism, crank-connecting rod and piston groups of the engine, pivot joint of the wheel assembly, steering, front wheel alignment angles, etc. , bore gauges, dial indicators, plumb lines, as well as special devices. The advantage of the methods of this group is the possibility of making accurate diagnoses, the simplicity of measuring instruments, and the disadvantages are high labor intensity, low manufacturability.

To group III include methods that estimate the parameters of related processes. For example, the tightness of working volumes is assessed when detecting and quantifying leaks of gases or liquids from working volumes, components and assemblies of a car. These working volumes include:

• combustion chamber
• the tightness of which depends on the state of the cylinder-piston group and the gas distribution valves
• cooling system
• engine power system
• hydraulic and pneumatic devices and mechanisms

By the intensity of heat release, it is possible to evaluate the work of friction of the mating surfaces of parts, the quality of combustion processes (for example, by the temperature of the exhaust gases), but such methods have not yet found wide application.

When creating means of technical diagnostics of vehicles, they are also widely used methods that assess the state of nodes and systems by the parameters of oscillatory processes... They can be divided into three subspecies:

1. methods for evaluating voltage fluctuations in electrical circuits
2. methods for evaluating the parameters of vibroacoustic signals (obtained during the operation of gears, valve mechanisms, bearings, etc.)
3. methods for evaluating pressure pulsation in pipelines (diesel testers work on the basis of this principle for diagnosing diesel fuel equipment)

The methods by which voltage fluctuations in electrical circuits are estimated are used to diagnose the engine ignition system from characteristic oscillograms of voltages in the primary and secondary circuits. The oscilloscope displays the processes occurring in the primary and secondary circuits of the ignition system during the time between successive spark discharges in the cylinders for visual inspection. The portions of the waveforms contain status information. From the oscillogram of the primary voltage, the angle of the closed state of the contacts is directly measured. According to the spark discharge voltage, the oscillograms of the secondary voltage determine the state of the spark plug gap. Comparing the obtained oscillograms with the reference ones, they reveal the characteristic malfunctions of the tested ignition system.

Vibroacoustic methods are used to measure low and high frequency vibrations of systems and elements of vehicles.

One of these methods is diagnostics based on periodically repeating work processes or cycles. The essence of this method is as follows. The working processes of intake, compression, combustion and exhaust, pressure changes in high-pressure fuel lines, oscillatory processes in the ignition system and others are often repeated. Since the patterns of change in the parameters of working processes in all periods are identical, it is enough to study the parameters of one cycle for diagnostics. For this, with the help of special converters, the parameters of one cycle are delayed, unfolded in time and displayed on a recording or indicating device.

A certain place is occupied by methods evaluating the physical and chemical composition of the spent the condition of components and assemblies and deviations from their normal functioning, for example, analysis of used oil, analysis of exhaust gases, etc. Diagnostics by the composition of the oil is carried out by analyzing its samples taken from the engine crankcase in order to determine the quantitative content of wear products of parts, as well as the presence of contaminants and impurities. The concentrations of iron, aluminum, silicon, chromium, copper, lead, tin and other elements in the oil make it possible to judge the rate of wear of parts. By the change in the concentration of iron in the oil, one can judge the rate of wear of the cylinder liner, crankshaft journals, and piston rings. The change in the concentration of aluminum is used to judge the rate of wear of pistons and other parts. The soil dust content characterizes the condition of the air filters and the tightness of the air supply path to the engine cylinder.