Method for evaluating dynamic damage of material under repeated impacts

Abstract

The invention discloses a method for evaluating the dynamic damage of a material under repeated impacts, which comprises the following steps of: 1. measuring and calculating the original average wave speed v0 of a test specimen prior to an impact test by using the ultrasonic method; 2. carrying out a repeated impact test on the test specimen; 3. Measuring by adopting an ultrasonic wave method and calculating the average wave speed vn of the test specimen after the nth impact; 4. calculating the damage factor of the test specimen after the nth impact: Dn=1-vn2/v02; and 5. calculating the arithmetic average of the damage factors of at least three test specimens made of the same material after the nth impact, and evaluating the dynamic damage degree of the material with factors under different impact times. The invention has simple measuring method, is suitable for measuring various materials of different characters, can be used for quantitative evaluation on the damage degree of materials and structures under dynamic load effects such as explosion, impact, penetration and the like, improves the accuracy and the reliability of the evaluation method, and can carry out quantitative comparison and evaluation on the repeated impact resistance of different materials.

Description

technical field The invention relates to an evaluation method, in particular to an evaluation method for dynamic damage of materials under multiple impacts. Background technique High-tech weapons, terrorist attacks, sudden explosions and impact accidents pose serious challenges to existing protective materials and structures. Protective engineering structures are often subjected to multiple impact loads during use, so it is necessary to design materials to resist multiple impacts, inhibit the damage and cracking process of materials under multiple impacts, and improve the ability of protective engineering structures to resist multiple impacts. Hu Shisheng and Zhang Lei of the University of Science and Technology of China used the SHPB device to repeatedly load the concrete long rod-shaped specimen at low speed, and the results showed that there was damage evolution inside the specimen, and this evolution also had a cumulative process (experiments on the spalling strength of ...

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Problems solved by technology

The multiple impact tests in the literature are all carried out at low strain rates, and the change proce

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