Subjective and objective failure search. Comparative characteristics of methods for direct assessment of the technical condition. Subjective and objective diagnostic methods. 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 very 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 sciences, where the result and the operation with objects form an invariant:

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

Psychology refers 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 seen 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 options for solving the problem fluctuated between two poles:

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

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

The problem of the objective method was first posed in behaviorism(J. Watson, 1913). As is known, observation and experiment were recognized as the only objective method for studying the psyche in behaviorism, which made it possible to study mental reality on the basis of the “black box” principle. Understood in this way, the objective method was based on those 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 ideas about the psyche, and in particular behaviorism, became their theoretical basis. Like the methods of scientific research in behaviorism, tests were designed in accordance with the rules of the classical ideal of scientificity. Without diminishing the great importance of the test method, we can say that the reliability and validity requirements of the test are quantitative indicators of how close the technique is to the ideal of Absolute Observation.

These principles have become the theoretical basis for more than just tests. So, A. G. Shmelev convincingly showed that questionnaires of personality traits are also based on a behaviorist interpretation of the concept of personality traits (see: Shmelev, 2002, pp. 51-52). Finally, the whole theory of psychological experiment, and in particular the concept of an ideal experiment, or an experiment of full correspondence, that has developed in psychology (Gottsdanker, 1982), is an attempt to make the experiment a method that has the qualities of an 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 also created in psychology, which were based on completely different initial philosophical and worldview premises. These are, for example, psychoanalytic therapy as a method practical psychology and projective techniques, most of which are based on psychoanalytic theory, - it is enough to recall the Jung association test, the Rorschach technique or the thematic apperceptive test. They fully corresponded to 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 own subjective world into the understanding of the mental reality of another person. Until now, in the English-language literature one can find opposition between objective and projective methods.

Psychologists have tried to overcome these extremes in different ways. For example, in the late 1930s various psychological theories are being created that represent a compromise between psychoanalysis and behaviorism (for example, the well-known theory of frustration - aggression by N. Miller and J. Dollard). These theories were created not only as a search for a “golden mean” between the psychological theories that dominated at that time in the United States. They were created as theoretical foundations for a method that would allow one to study the psychological reality of a person, while remaining as objective as possible. In this vein, L. Abt, D. Rapoport, S. Rosenzweig and many other representatives of the projective psychology of that time conducted research. 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, if 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:

“Because of the desire to conform to scientific models (i.e., traditional, classical ideals of scientificity), the focus on the study of the unique, single (which expressed some general trend present in the humanities) has been increasingly transformed into a line of studying deviations from the average individual (from "stamped" content, from "cliché plots", etc.)"
Burlakova, 2001, p. 12.

The above plot from the history of psychodiagnostics reflects some common features of the search for an objective method in psychology. The situation in which psychology finds itself in this search has become the subject of methodological analysis. This is how ideas about the nomothetic and ideographic approaches and the relationship between them, formulated by G. Allport, appeared. As already mentioned, psychosemantic methods have become one of the attempts to overcome the extremes of the nomothetic and ideographic approaches. Started back in the 1950s, studies of human subjective semantics are being successfully carried out to this day, including in modern domestic 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, the method of natural experiment proposed by A.F. Lazursky should be attributed to such achievements. According to A.F. Lazursky, a natural experiment was a means of overcoming the shortcomings of a laboratory experiment and at the same time made it possible to realize scientific approach to the study of the psyche.

In the first post-October years, domestic psychology experienced the strongest influence of Marxism, which became the state ideology. Under these conditions, new areas of psychology developed, the purpose of which was an objective study of the psyche. These included the reactology of K. N. Kornilov and the reflexology of V. M. Bekhterev. The method of reflexological research was analyzed by L. S. 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 subjective reality of the subject in a reflexological study. 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 L. S. Vygotsky was the creation of a method of formative experiment, or an instrumental method, as he himself called it. First of all, the instrumental method is a means of studying the psychological tools of a person, the existence of which for Vygotsky is an axiom. 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 us to study the process of re-creating psychological reality when a person masters tools (for example, in training and education).

In later years, several directions emerged in Russian psychology in which this problem was solved. One of them is the further development of L. S. Vygotsky's experimental-forming method. The formative experiment method was developed in educational psychology(the method of developing education by D. B. Elkonin and V. V. Davydov), in developmental psychology (the method of phased (planned) formation of mental actions and concepts by 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. The analysis of the problem required reflection on the philosophical premises used to create an objective method. The initial philosophical prerequisites are a number of provisions, which were subsequently developed by V.P. Zinchenko and M.K. Mamardashvili in later works:

1. the indecomposability of the phenomena of psychological reality into elements;
2. the need to revise the traditionally sharp opposition between the material and the ideal, external and internal, objective and subjective;
3. the introduction of internal (psychological) reality into the object of study: “... the acceptance of the fact that subjectivity itself enters into 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 beyond her in the form of a mysterious soul”;
4. consideration of consciousness as a psychological reality, located in the gap of a lasting experience, allowing to delay the 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, non-Euclidean field in terms of its spatial characteristics, in which both the objective content of external objects and the subject of cognition, communication and action are simultaneously represented.

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-functional models of mental "reality, which are "both a visible thing and an understanding" (Ibid., p. 121). In the works of V.P. -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, although in a somewhat different way. The parameters of the semantic field or personal factors are measurements of the subjective reality of a person. However, personality psychology proceeds from the fundamental possibility of their objectification with the help of psychometric methods, procedures of subjective scaling, ranking lists of values. Naturally, personal factors or parameters of a person's semantic space are not thought of as spatial in the ordinary 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 concrete scientific methodology, consider the projective method as a means of bringing outside the internal dialogue of a person. In this situation, the psychodiagnostic is assigned the role of a mediator (intermediary), which contributes to the objectification of the internal dialogue with the help of external means(projective technique).

The examples we have given 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 research procedures and 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 rejection of a job, even for hardened candidates, it sometimes causes a fit of pessimism. But is it always necessary to scold yourself for the mistakes you made?

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

"Why was I rejected?" - some applicants are tormented, going over in memory every moment of the interview and every phrase in the resume. Such reflection is, of course, 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 applicants are rejected because they are too good.

So, consider why you might be denied. 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 hired due to certain circumstances in the company or due to not quite correct recruiter ratings).

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, for a specific vacancy, they are looking for a specialist with years of experience work, and you have not yet had time to purchase it. Such restrictions can be attributed to discrimination, but it is better to find out all the requirements before the interview in order to avoid misunderstandings during the conversation with the recruiter.
• 2A resume stands out too much from the crowd for some reason, and the recruiter finds ways to stand out inappropriate. For example, a candidate jokes a lot and not always successfully in his CV (for example, he said about himself: “I studied something and somehow”; “I am looking for a job as a spider-man”, etc.). Or, for some reason, he marked information about each place of his work in different colors - blue, pink, yellow. Or he completely abandoned the business style of presentation in favor of some kind of “creativity”.
• 3At the interview, the HR manager found the candidate’s appearance to be inconsistent with the corporate culture companies. For example, everyone goes to work in business suits, and the applicant showed up in frayed jeans. Or with too bright manicure (in too short a skirt, with massive earrings, in dirty shoes, etc.).
• 4During the interview, it became apparent that the candidate had lied on his CV or had embellished his experience and education too much. No comment: you can't make a career out of cheating.
• 5During 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. Uninteresting vacancy - do not send a resume.
• 6At the interview, the applicant asked too many questions about vacation and salary and too few questions about duties and rules of work.
• 7 Candidate's illiterate speech, especially if he is applying for a position where constant communication with clients, partners, etc. is expected.
• 8 Uncertainty, stiffness of the applicant or, on the contrary, his excessive looseness and self-confidence.
• 9During the interview, the applicant was critical of his former boss, company, and colleagues. Such a candidate may be considered a conflict or, worse, a scandalous person.
• 10The applicant expressed doubts about the qualifications of an HR manager. “How can this girl evaluate me, an experienced specialist?” - Recruiters often face this position, especially among older applicants. Remember: the HR manager evaluates the basic suitability of your resume for the job and your overall suitability. Professional qualities are assessed by a potential leader if you pass the selection from an HR manager.
• 11Alas, this is a reality: a candidate may be too young or too “adult” for a particular vacancy. Most likely, this reason will not be announced to you, however age limit is commonplace for many companies.
• 12The candidate did not show himself to be a polite person: did not say hello (or did not say hello in a friendly enough way), did not let the girl through the door, did not say “goodbye”, etc.
• 13Applicant tried to flirt with recruiter.
• 14During the interview, the candidate's phone rang. The fact that he did not turn it off during the interview is not good in itself. But the fact that he decided to answer the call may put an end to employment in this company.

Subjective reasons

Now consider the subjective reasons for a possible rejection - those because of which you should not worry too much, because you were not rejected at all because you are not qualified enough or do not know business etiquette. And why?

• 1 The resume seems too good to the recruiter - there is a clear overqualified, that is, an excessively high qualification of the applicant for this vacancy. It is believed that a “too smart” candidate is far from the best option to close a vacancy, especially if it does not involve career growth. There are several disadvantages: a specialist can get bored quite quickly due to the lack of interesting tasks, lose motivation and even leave the company, besides, he needs to be paid more.
• 2Another scenario from point 14: during the interview, the candidate's phone rang. The applicant dropped the call, but the recruiter with a fine aesthetic taste has a complete rejection of the song set as the call (for example, "Vladimirsky Central"). Or any other melody - the concept of "delicate taste", as you know, is loose.
• 3The candidate does not look like a real team player in the eyes of the recruiter - in him, as it seems to the HR manager, there is too much individualistic beginning.
• 4At the same time, the company may also have rather specific wishes for the appearance of the future employee. This is especially true for specialists working with clients or, to one degree or another, being the "face of the company" - secretaries, PR managers, etc. Is it worth it to reproach yourself for the fact that you were born, for example, not a blonde with legs from your ears, but a brown-haired woman of ordinary complexion?
• 5During the interview, the applicant told a joke that the recruiter did not like.
• 6Too much competition for this job. You may be a perfect fit for a job, but three or four other candidates will be just as perfect…
• For some reason, the 7HR manager 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 employees are vegetarians, and you asked if there is a cafe nearby with good meat dishes.
• 8Finally, the applicant could simply not like a recruiter or a potential manager as a human being. The smell of perfume is too strong, an excessively loud or, on the contrary, a very quiet voice, an 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 some mistakes. Recruiters are people too and can make mistakes, just 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. Defectoscopy methods. Defectoscopic control by magnetic method.

Methods for assessing the condition of machines and equipment

Types of defects and their technical diagnostics

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

Defects vary in

Dimensions;

location;

By nature;

Origin.

Defects can form during the process

Melts and castings (shells, pores, friability, inclusions, etc.);

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

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

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

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

Size or scale of the defect- a quantitative characteristic of the deviation of the actual dimensions and (or) 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 manifestations of technical conditions, develops methods and tools for their detection and localization of defects in technical systems, as well as principles for organizing and using diagnostic systems.

The task of diagnosing is a preventive examination of the machine as a whole or its components, mainly without disassembly; determination of the technical condition of mechanisms, checking their performance, prompt detection of faults; determination and prediction of possible deviations in operating modes; collection of initial data to predict the residual life and reliability of components.

Distinguish between subjective and objective search for failures and malfunctions.

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

Objective method - establishing quantitative estimates based on instrumentation, stands, special tools.

In turn, control methods can be divided into

Direct - reliable functional relationships between 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).

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

A characteristic feature of fault 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 detect deviations of parts of nodes from a given relative position. At detailed fault detection determine the reusability of parts and the nature of the required repair. Sort parts into the following groups:

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

parts with wear above the allowable, but suitable for repair;

parts with wear above the allowable and unsuitable for repair.

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

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

For visual control of the condition 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). At the same time, the ratio of the length of the endoscope to its cross section is significantly more than one. Exist 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, potholes and other defects with sizes 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 5-10 °. Field of view diameter 3-20 mm.

Flexible fiber-optic endoscopes make it possible to transmit an image of a controlled object along a curvilinear 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 detect violations of the operating mode of parts that make up friction pairs.

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

by measurement with the help of a measuring tool, as a rule, the visual inspection of 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 both in the longitudinal (taper, barrel-shaped, etc.), and in pepper (ovality, faceting, etc.) sections of the part. When measuring parts, a standard universal measuring tool is used (calipers, micrometers, micrometric inside gauges, etc.).

The deviation of the shape of parts such as bodies of revolution in cross sections is determined using round gauges (for example, mod. 256, 289, 290). When fault detection of parts is carried out in the conditions of a specialized repair company, visual-optical devices (projectors), devices for automatic control of linear dimensions, etc. are used for dimensional control. The measurement method is most often used when determining defects in cylinders, cylinder liners, 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 wear rate of parts in the study of compressor life (life tests). The use of this method under production conditions is complicated due to the insufficient determination of the wear site, as well as the lack of strict dependences of wear, expressed through a change in the size of the wear surface, on a 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 fault detection.

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

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

Profiling - graphic recording of a profile.

With the surface activation method, the surface (section, point) of the part being examined is subjected to preliminary irradiation with a stream of alpha particles. As a result, a mixture of radioactive isotopes is formed in the microvolume, emitting gamma radiation. As the activated volume wears out, the radiation activity decreases, registered by radiometric equipment (Fig. 14).

Detection of parts by geometric features (wear, deformation, roughness, etc.) is important information about the technical condition of the objects being examined. However to estimate the resource parameters, information is also needed 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. 9.

The purpose of hydropneumatic testing is to determine the tightness of the assembly, welding, etc., as well as testing the strength of the products themselves.

When conducting hydropneumatic tests, products are subjected to high blood pressure, hold for a certain amount of time. For example, a block crankcase assembly with covers is tested for strength by hydraulic pressure, as a rule, 3.5 MPa with exposure, under pressure for 10 minutes. During the test, the personnel must be behind an impervious partition. It is allowed to approach the product for testing only after holding the tested crankcase under pressure. If during inspection of the crankcase under fluid pressure, leaks, dew, sweating, etc. are observed, then the crankcase is rejected.

Gradually raise the pressure 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. Good parts are branded.

The goals of hydropneumatic tests carried out during the fault detection of compressor parts coincide with the goals of similar tests carried out during the diagnostics of compressors as a whole.

Cases, crankcases, cylinders, cylinder bushings, fittings, pipelines, etc. are subjected to hydropneumatic testing.

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

For strength, block crankcases are tested 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 exposure, under pressure for 10 minutes. During the test, the personnel must be behind an impervious partition. It is allowed to approach the product for testing only after holding the tested crankcase under pressure. If during inspection of the crankcase under fluid pressure, leaks, dew, sweating, etc. are observed, then the crankcase is rejected.

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

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

Gradually raise the pressure 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. Good parts are branded.

At a number of plants, when testing block crankcases for density, their outer surfaces are covered with a soapy solution, to which a few drops of glycerin are added to prevent drying. The tests also control the appearance of bubbles.

Preparation for hydropneumatic testing of parts of freon compressors is carried out especially carefully. Parts are cleaned and blown with 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 underwater using dry air or nitrogen.

Defectoscopic control by magnetic method.The magnetic particle method is designed to detect surface discontinuities in metal (cracks, sunsets, inclusions, delaminations, etc.) by detecting stray magnetic fields that occur near defects after magnetization of test objects.

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

With the magnetic particle method to detect 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 to defects with an opening width of 10 μm and a minimum length of a conditional defect of 0.5 mm.

The magnetic particle control method consists of the following operations:

preparation of the part for inspection,

part magnetization,

applying a magnetic powder or suspension to a part,

detail inspection,

assessment of control results

demagnetization.

Preparation for control 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 type 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 hard to see, then it is sometimes covered with a thin layer of white paint (nitro lacquer).

The sensitivity and ability to detect defects depends on right choice 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 they cannot be demagnetized. Internal defects can be detected using alternating (and pulsed) current, if its amplitude is increased by 1.5-2.5 times compared with the current amplitude calculated to detect surface defects. Magnetization is carried out different ways: passing 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 from the outside with a part of the coil. Longitudinal magnetization is more often carried out with the help of a solenoid and less often with the help of electromagnets (permanent magnets are used even less often).

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 location of the defect in the direction of the magnetic field is necessary. The part must be checked in two mutually perpendicular directions.

Magnetic powder is prepared from dry, finely ground iron minium or from pure iron scale, 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.

Apply water, kerosene, oil magnetic suspensions.

To obtain 1 liter of an aqueous suspension, dilute 15-20 g of oleic or laundry soap 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. After that, add hot water up to 1 l.

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

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

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

The inspector should inspect the part after running off the main mass of the suspension, when the pattern of powder deposits becomes unchanged.

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

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

Powder deposits on hairline appear as straight or slightly curved thin lines. Powder deposition over cracks has the form of clear broken lines with dense powder deposition. Rolls of powder, settled under flocks, are clear and sharp short dashes, sometimes curved, located in groups (less often single). Zakovy give a clear deposition of powder in the form of smoothly curved lines. Pores and other point defects are revealed 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 the presence of defects (multidirectional cracks, lack of penetration, shells, etc.) on the surface and at a depth of up to 5 mm. Ferroprobe installation "Radian-1M" allows to detect defects with dimensions of at least 0.15 mm in depth and 2 mm in length.

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

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

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

1.objective Vulnerabilities (Emissions Associated with Technical Means, Activated, Determined by the Features of the Elements, Determined by the Features of the Informatization Object)

2.subjective vulnerabilities (Mistakes (negligence), Violations, Psychogenic)

3.Random Vulnerabilities (Failures and Failures, Indirect Causes)

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

1)related technical means radiation :

a) electromagnetic (side radiation of elements of technical means, cable lines of technical means, radiation at frequencies of operation of generators, at frequencies of self-excitation of amplifiers);

b) electrical (induction 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);

in) sound (acoustic, vibroacoustic);

2)activated :

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

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

3) defined features of the elements :

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

b) elements subject to exposure to electromagnetic fields (magnetic media, microcircuits, non-linear elements subjected to RF interference);

4)determined by the features 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) organization of information exchange channels (use of radio channels, global information networks, leased channels).

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

1) Mistakes :

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

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

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

2) Violations :

a) mode protection and protection (access to the facility, access to technical facilities);

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

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

d) regime privacy (off-hours employees, 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 hardly predictable and their elimination is possible only through a set of organizational, engineering and technical measures to counter IS threats:

Crashes and failures :

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

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

in) software failures (operating systems and DBMS, application programs, service programs, anti-virus programs);

d) failures electricity supply (equipment processing information, providing and auxiliary equipment).

Methods for diagnosing vehicles are divided into subjective and objective. Subjective methods are based on methods for determining the technical condition of a car by the output parameters of dynamic processes. However, the receipt, analysis of information, as well as the adoption of a decision on the technical condition are made with the help of human senses, which, of course, has a fairly high error.

Subjective Methods

The following subjective methods are most widely used:

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

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

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

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

• increased clearance between the 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 areas of the crank mechanism when changing the speed of the crankshaft
• excessive advance or delay of fuel injection - by the nature of the exhaust sound (with early injection - “hard work”, with late - “soft”)
• car clutch malfunctions - by noise and knocks when shifting gears, etc.

By feeling the mechanism, you can determine the following faults:

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

Based on logical thinking, we can conclude the following faults:

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

Objective Methods

Objective methods are based on the measurement and analysis of information about the actual technical condition of the vehicle elements using control and diagnostic tools and by making a decision on specially developed diagnostic algorithms. The application of these or those methods essentially depends on the goals that are solved in the process of technical preparation of vehicles. However, due to the complexity of the car 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 measuring and the physical essence of diagnostic parameters that are most suitable for use depending on the task of diagnosing and the depth of diagnosis.

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

Group I methods are based mainly on simulating the speed and load modes of the car and determining the output parameters under 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. Methods of diagnostics according to the parameters of operational properties give general information about the technical condition of the vehicle. They allow you to evaluate the main performance qualities of the car:

• brake
• power
• 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 value of these parameters or gaps that determine the relative position of parts and mechanisms. Such diagnostics are carried out in the case when these parameters can be measured without disassembling the interfaces of rubbing parts. Structural parameters can be clearances in bearing assemblies, valve mechanism, crank and piston groups of the engine, pivot connection of the wheel assembly, steering, front wheel alignment angles, etc. Structural parameters are diagnosed using measuring tools: probes, rulers, calipers , inside gauges, dial gauges, plumb bob, 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 III group include methods that estimate the parameters of accompanying processes. For example, the tightness of working volumes is evaluated when detecting and quantifying leaks of gases or liquids from working volumes, components and assemblies of a car. These workspaces include:

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

The intensity of heat release can be used to estimate 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 according to the parameters of oscillatory processes. They can be divided into three subspecies:

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

The methods by which voltage fluctuations in electrical circuits are evaluated are used to diagnose the engine ignition system from characteristic voltage oscillograms 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 examination. Waveform sections contain status information. According to 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, characteristic faults of the tested ignition system are revealed.

Vibroacoustic methods are used to measure low- and high-frequency oscillations of vehicle systems and elements.

One such method is diagnosing by periodically repeating workflows 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 changes in the parameters of work processes in all periods are identical, it is enough to study the parameters of one cycle for diagnosing. To do 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.

They occupy a certain place methods that evaluate the physical and chemical composition of spent the condition of components and assemblies and deviations from their normal functioning, for example, used oil analysis, exhaust gas analysis, etc. Diagnosis 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 wear rate of parts. By changing the concentration of iron in the oil, one can judge the wear rate of the cylinder liner, crankshaft journals, and piston rings. The change in aluminum concentration is used to judge the wear rate of pistons and other parts. The content of soil dust characterizes the condition of the air filters and the tightness of the air supply path to the engine cylinder.