弹体侵彻混凝土靶体的尺寸效应分析

由于混凝土靶体抗刚性弹侵彻实验大多基于缩比弹体展开，侵彻深度相似律是否成立显得尤为重要。在侵彻相似模型基础上，综合分析已有侵彻实验数据及经验公式，发现侵彻深度在通常情况下存在尺寸效应，且无量纲侵彻深度随弹体尺寸变大而增大。但如果模型以及原型实验中弹体与混凝土靶体（包括粗骨料）严格等比例设计，侵彻深度相似律是成立的。不变的骨料特征（粗骨料未随弹体尺寸缩放）是引起侵彻实验以及侵彻经验公式中尺寸效应的主要原因。为研究由粗骨料引起的侵彻尺寸效应，开发了混凝土二维细观有限元建模程序，细观数值实验成功地反映出了侵彻尺寸效应，考虑模拟尺寸效应后的侵彻公式能较好地预测不同尺寸侵彻实验。

Analyses of the size effect for projectile penetrations into concrete targets

Whether the replica scaling law holds or not is of great significance because penetration tests of concrete targets against rigid projectiles are commonly conducted in a reduced scale. In this paper, based on the replica scaling model and the analyses of penetration tests with various sizes and empirical formulae, we found that there exists a size effect in general for penetration depth, and the dimensionless depth increases with as does the size. However, the replica scaling law is satisfied for the penetration depth in rigid projectile penetrations, as long as the scaling is done strictly for both projectiles and concrete targets, including the coarse aggregates. We also found that the coarse aggregates of an invariant size (not replica-scaled) are the major factor accounting for the size effect in penetration depth found in tests and empirical formulae. To find out about the size effect resulting from aggregates, we developed a 2D mesoscopic finite element model for concrete target and conducted numerical simulations that successfully represent the size effect, thereby proving that penetration formula with size effect considered could well predict the penetration tests with different size.