Efficient visual detection method suitable for low-energy impact damage of composite material

Abstract

The invention discloses an efficient visual detection method suitable for low-energy impact damage of a composite material. The method comprises the following steps: obtaining impact energy E absorption of a brittle-tough double-layer paint film by adopting a series of impact tests; determining an impact energy threshold value EBVID of the composite material, performing an impact test on the prepared brittle-tough double-layer paint film / composite material, determining E absorption according to a crack propagation pattern of the brittle-tough double-layer paint film, and calculating residual impact energy E residual directly acting on the composite material in combination with the loaded impact energy; and detecting the impact damage, and when E residual is greater than or equal to EBVID,indicating that the impact damage is almost invisible to eyes. By establishing a corresponding relationship among E absorption, a paint film crack propagation form, E residual and EBVID, impact damageis effectively amplified, the internal damage degree of the composite material workpiece is equivalently evaluated through the crack propagation form of the paint film after impact, damage to the subsequent service process due to damage is reduced, and nondestructive testing work is avoided.

Description

technical field [0001] The invention belongs to the technical field of non-destructive testing of composite materials, and relates to a high-efficiency visual detection method suitable for low-energy impact damage of composite materials, and is suitable for the judgment process of the internal quality of composite material parts after impact damage. Background technique [0002] Composite parts are extremely sensitive to external impacts. During their service, impact damage is the main damage mode of composite structures. For high-energy impacts, most of the damage caused is penetrating damage, and the surface will show For relatively obvious damage features, inspectors can easily determine the repair or replacement process to maintain the damaged area through the surface damage features supplemented by non-destructive testing conclusions, so as to avoid the impact of internal damage on the service process of composite materials. However, compared with high-energy impacts, l...

AI Technical Summary

Problems solved by technology

However, compared with high-energy impacts, low-energy impacts have a higher probability of occurring during the service of composite parts, and generally do not cause visually detectable damage to the impacted surface, and it is difficult for inspectors to pass through the surface of the part. Directly observe and describe the structural damage status. If the internal damage detection process is not carried out, the workpiece may experience large internal damage without any signs on the surface, which will seriously affect the safety and reliability of the structure.

Therefore, it is necessary to use a large number of non-destructive testing methods such as ultrasonic C-scan and X-ray to evaluate the damage form and damage degree. Not only there are problems such as large investment in testing equipment and complicated operation process, but also relatively high requirements for the technical level of testing personnel and testing environment. High, for the internal damage judgment process of large-scale composite parts in service, it cannot meet its fast and efficient detection requirements