Device and method for measuring lightning impact force and lightning fracture damage of carbon fiber laminates

Abstract

The invention discloses a measurement device and method for lightning impact force and lightning fracture damage of a carbon fiber laminated plate with common-mode interference suppression performance. Through a certain length and a certain cross-section of the lightning impact force transmission insulating rod, it is transmitted to the piezoelectric sensing unit with a shielded shell, so that the measurement of the impact force of the tested carbon fiber composite laminate can be free from the influence of strong lightning current electromagnetic interference; through By adjusting the amplitude of the lightning current output by the controllable intensity lightning current generator, the mathematical analytical formula between the lightning impact force and the lightning current parameters of the tested carbon fiber composite laminate can be obtained; at the same time, by changing the tested carbon fiber The distance between the composite laminate and the piezoelectric sensor can obtain the response time characteristics of the lightning impact force, which provides theoretical support for the mechanism research of the lightning damage effect of the tested carbon fiber composite laminate.

Description

technical field [0001] The invention belongs to the measurement technology of the mechanical effect of lightning strikes on materials, and relates to a method for measuring the impact force of lightning strikes on carbon fiber composite materials, in particular to a device and method for measuring lightning strike force and lightning fracture damage of carbon fiber laminates. Background technique [0002] Carbon fiber composite materials have the characteristics of low density, high strength, high modulus, high temperature resistance, chemical corrosion resistance, etc., and are widely used in various fields such as aerospace, military and civil industries. With the increasing use of carbon fiber composite materials in aircraft structures such as large aircraft, high-intensity lightning strikes will cause serious damage such as fiber fracture, resin pyrolysis, and deep delamination of carbon fiber composite materials. Therefore, the lightning damage and lightning protection ...

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Problems solved by technology

However, in the process of lightning attachment, is the lightning impact force formed due to the ionization of channel gas caused by high voltage related to the fracture and delamination damage of carbon fibers? The current public literature cannot give a good explanation

At the same time, the lightning damage calculated based on the thermoelectric coupling modeling of the tested carbon fiber composite laminate can only reflect the lightning damage caused by the Joule heat injected by the lightning current after the lightning strikes the attachment point, while for other mechanical effects, such as the lightning damage before the attachment point The lightning impact force and the implosion impact force formed by the pyrolysis gas of the tested carbon fiber composite laminate resin cannot be characterized; in addition, the invention patent ZL 201510579759.4 discloses the method of lightning impact force of carbon fiber composite materials, but there are the following problems:

[0004] (1) The clamping method of the tested carbon fiber composite laminate is upper and lower clamping, that is, the lightning strike is injected from one surface of the tested carbon fiber composite laminate and flows out from the other plane of the tested carbon fiber composite laminate. The lightning impact force measured by the clamping method cannot fully represent the impact force when the actual large aircraft structure is subjected to lightning

[0005] (2) Below the carbon fiber laminate is a metal plate electrode. A circular or square slot for installing an insulating plate is opened in the center of the plate electrode, and a slot for installing a piezoelectric sensor is opened in the center of the insulating plate. The surface of the piezoelectric sensor and the The surface of the insulating plate is flat and in close contact with the tested carbon fiber composite laminate. However, due to the light weight of the carbon fiber laminate in the experimental study, the contact between the carbon fiber laminate and the impact piezoelectric sensor is not in firm contact, resulting in The measured impact force has a large dispersion, and it is impossible to accurately characterize the lightning impact force of lightning strikes on carbon fiber laminates

[0006] (3) Because the lightning impact piezoelectric sensor is placed in the strong electromagnetic environment of the carbon fiber laminate lightning impact, the lightning impact signal extracted by the piezoelectric sensor has strong electromagnetic interference, which causes a large deviation in the impact force measurement

[0007] (4) During the action of lightning strikes and carbon fiber composite materials, the instantaneous relationship between lightning impact force and lightning current response time cannot be accurately given, which directly affects the research on the lightning damage mechanism of lightning strikes and carbon fiber composite materials and the design of carbon fiber lightning protection materials and protective structures.

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