CN103412007A - Method for monitoring fatigue crack - Google Patents

Abstract

The invention discloses a method for monitoring a fatigue crack, belonging to the technical field for verifying a fatigue property and the service life of a helicopter component. According to the method, the conductivity of a silver plated layer which is adhered to the helicopter component subjected to a fatigue test is utilized, the silver plated layer is accessed to a closed circuit, when a fatigue testing component has the crack, the rigidity of the crack part is reduced, the silver plated layer is broken because of the opening and closing process of the crack along with the periodic change of a fatigue testing load, the closed circuit is subjected to open circuit, a closure signal for opening and closing a signal circuit is generated, and the closure signal is further fed back to a computer, and meanwhile, the computer test circulation time record is controlled by combination of a testing servo. By utilizing the method, the fatigue circulation times corresponding to the crack and the surface crack generating positions can be precisely confirmed; the reliability of fatigue testing data is greatly improved; the reliability is not limited by monitoring parts and component shapes; meanwhile, complex processes are omitted, the operation is easy and feasible, and the execution is convenient.

Description

A kind of method of monitoring fatigue crack

Technical field

A kind of method of monitoring fatigue crack of the present invention, belong to the fatigue behaviour of verifying helicopter structural element and the technical field in life-span.

Background technology

Torture test checking is the fatigue behaviour of helicopter structural element and the important way in life-span, and test number (TN) and position data when in test, surface crack occurs are the call parameters of fatigue behaviour and life prediction.

The personnel that at present mainly rely on Non-Destructive Testing for the detection of helicopter structural element fatigue test piece surface crack carry out to testpieces that regular detection or torture test personnel's means such as visual realize.Main common method has osmosis, magnetic particle method, magnifier visual method etc., and wherein the most convenient, good economy performance is exactly osmosis.The osmosis cardinal principle is: the bleeding agent that will be dissolved with fluorescent dye or illuminating colour is applied to the test component surface.Bleeding agent is opened in surperficial tiny defect because capillary action can penetrate into all kinds, removing is attached to unnecessary bleeding agent on the test specimen surface, drying and apply developer after, under black light or white light, observe, fault location can correspondingly send respectively yellowish green fluorescence or present redness and just can find with visual examination.

Shortcoming is:

The test component surface breakdown is detected and do not accomplish to occur can detect and detect in real time.

Depend on reviewer's experience, conscientious degree and eyesight agility etc.

The testing staff will carry out observation and inspection frequently.

In parts or full machine torture test, due to the test component complexity, cause some concealment part to adopt conventional means to detect, detect extremely difficult.

Summary of the invention

Purpose of the present invention can be monitored the concern position of testpieces as requested, can judge accurately whether the crackle that monitoring site occurs that the time of crackle is convenient to monitoring test spare key monitoring position situation occurs, be convenient to the health condition of testpieces in real-time monitoring torture test process, and this middle detection does not depend on people's experience, conscientious degree has realized real-time detection.Significantly improved the reliability of helicopter component torture test.

Technical scheme of the present invention is that the method is taked following steps:

1) will carry out polishing smooth after the parts emphasis monitored area depainting of torture test;

2) in temperature, be in 20 ℃ ~ 40 ℃ situations, at the even brushing insullac in the parts emphasis monitored area of torture test, brushing in 2 ~ 3 hours once, is brushed three times altogether;

3) after guaranteeing that enamelled coating parches fully, sticking film connection terminal one [2A], film connection terminal two [2B] on the parts emphasis monitored area of torture test;

4) on the parts emphasis monitored area of torture test, drawing one with silver powder is 0.01m ~ 0.05mm, the silver-plated layer line [1] that covers the parts emphasis monitored area of torture test without intersection, thickness continuously, silver-plated layer line [1] originates in film connection terminal one [2A], end at film connection terminal two [2B], guarantee that silver-plated layer line [1] is good with being connected of film connection terminal [2], and do not affect assembling, silver-plated layer line [1] width is even, and width range is 0.8 ~ 1.2mm;

5) after guaranteeing that silver-plated layer line [1] parches fully, by film connection terminal one [2A], film connection terminal two [2B] access switching signal Acquisition Circuit [3];

6) measuring switch signal acquisition circuit [3] resistance, if this resistance is infinitely great, show that the continuity of silvering line [1] is bad, and crack conditions is arranged; If silvering line [1] skin effect phenomenon is arranged, the tack that shows silvering line [1] is bad, as above two kinds of situations occur, and the silvering line [1] of drawing painting need be rejected, repeating step one to four, until switching signal Acquisition Circuit [3] resistance is normal and silvering line [1] without the peeling situation.

Beneficial effect of the present invention: adopt the present invention, generation, position and the crackle that at first can detect reliably torture test parts monitoring site surface crack corresponding cycle index while occurring.Do not rely on the subjective factors such as reviewer's experience, conscientious degree, vision agility.Significantly improve the reliability of fatigue data, simultaneously, the restriction of not monitored position and part shape.Secondly, without complicated technological process, operation is simple, and it is convenient to implement.

The accompanying drawing explanation

Fig. 1: parts auricle silver coating is scrawled mode

Fig. 2: the parts turning goes out silver coating and scrawles mode

1 is silver-plated layer line, and [2A] is film connection terminal one, and [2B] is that film connection terminal two, 3 is transition section, and 4 is cowl lip

Embodiment

Embodiment

1, a kind of method of monitoring fatigue crack of the present invention, is characterized in that, the method is taked following steps:

1) will carry out polishing smooth after the parts emphasis monitored area depainting of torture test;

2) in temperature, be in 25 ℃ of situations, at the even brushing insullac in the parts emphasis monitored area of torture test, brushing in 2 hours once, is brushed three times altogether;

3) after guaranteeing that enamelled coating parches fully, sticking film connection terminal one [2A], film connection terminal two [2B] on the parts emphasis monitored area of torture test;

4) on the parts emphasis monitored area of torture test, drawing one with silver powder is 0.01mm, the silver-plated layer line [1] that covers the parts emphasis monitored area of torture test without intersection, thickness continuously, silver-plated layer line [1] originates in film connection terminal one [2A], end at film connection terminal two [2B], select slightly harder pen to dip in silver powder and draw painting, guarantee that silver-plated layer line [1] is good with being connected of film connection terminal [2], and do not affect assembling, silver-plated layer line [1] width is even, and width range is 0.8mm;

5) after guaranteeing that silver-plated layer line [1] parches fully, by film connection terminal one [2A], film connection terminal two [2B] access switching signal Acquisition Circuit [3];

6) measuring switch signal acquisition circuit [3] resistance, if this resistance is infinitely great, show that the continuity of silvering line [1] is bad, and crack conditions is arranged; If silvering line [1] skin effect phenomenon is arranged, the tack that shows silvering line [1] is bad, as above two kinds of situations occur, and the silvering line [1] of drawing painting need be rejected, repeating step one to four, until switching signal Acquisition Circuit [3] resistance is normal and silvering line [1] without the peeling situation.

Claims (1)

1. a kind of method of monitoring fatigue crack of the present invention, is characterized in that, the method is taked following steps:

1) will carry out polishing smooth after the parts emphasis monitored area depainting of torture test;

2) in temperature, be in 20 ℃ ~ 40 ℃ situations, at the even brushing insullac in the parts emphasis monitored area of torture test, brushing in 2 ~ 3 hours once, is brushed three times altogether;

3) after guaranteeing that enamelled coating parches fully, sticking film connection terminal one [2A], film connection terminal two [2B] on the parts emphasis monitored area of torture test;

4) on the parts emphasis monitored area of torture test, drawing one with silver powder is 0.01m ~ 0.05mm, the silver-plated layer line [1] that covers the parts emphasis monitored area of torture test without intersection, thickness continuously, silver-plated layer line [1] originates in film connection terminal one [2A], end at film connection terminal two [2B], guarantee that silver-plated layer line [1] is good with being connected of film connection terminal [2], and do not affect assembling, silver-plated layer line [1] width is even, and width range is 0.8 ~ 1.2mm;

5) after guaranteeing that silver-plated layer line [1] parches fully, by film connection terminal one [2A], film connection terminal two [2B] access switching signal Acquisition Circuit [3];

6) measuring switch signal acquisition circuit [3] resistance, if this resistance is infinitely great, show that the continuity of silvering line [1] is bad, and crack conditions is arranged; If silvering line [1] skin effect phenomenon is arranged, the tack that shows silvering line [1] is bad, as above two kinds of situations occur, and the silvering line [1] of drawing painting need be rejected, repeating step one to four, until switching signal Acquisition Circuit [3] resistance is normal and silvering line [1] without the peeling situation.

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