Analysis of size effect for scaled penetration test of rigid projectiles
The size effect of scaled penetration tests is an important issue affecting the application of the test results.In order to improve the accuracy of scaled test results converting to prototype tests,by analyzing the theoretical formula of penetration depth of rigid projectile,the main factors causing size effect are clarified.The experimental determination methods of diameter coefficient and other key parameters in penetration depth formula are given.The theory and method of converting the results of model tests to prototype test are given.The results show that for rate-dependent materials,strain rate leads to the size effect.For rate-independent materials,the scale itself also leads to size effect,which is essentially due to the size effect in the development of medium failure.The smaller the scale,the more obvious the size effect.The size effect is also related to the properties of the material and the diameter of the prototype projectile.For the experiment with a scale of 0.1,for safety reasons,the diameter coefficient is taken as 1.3.The material parameters related to the size effect can be obtained by two sets of penetration tests with different scales.