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根据弹性力学、能量守恒定律以及内应力假说的基本原理,从材料的非均一性、多相性出发,建立了一组描述脆性材料强度指标和弹模指标尺寸效应的方程.利用本假说的理论公式与实验数据Weibull 理论作了对比,结果表明本假说的理论公式在描述材料强度尺寸效应时具有良好精度,可很容易地说明为什么尺寸效应在试件尺寸大到一定程度会消失.该假说认为内应力会受到试件边界面的释放, 称为内应力的边界效应,试件尺寸越大则边界面相对越小, 因而内应力场或者说内应力能会随试件尺寸加大而加大,边界效应在引起材料强度指标随试件尺寸加大而减小的同时, 还会引起材料初始切线弹模随试件尺寸加大而加大的弹模尺寸效应
According to the basic principles of elasticity, energy conservation law and internal stress hypothesis, a set of equations describing the size effect of brittle material strength index and the elastic modulus index are established based on the heterogeneity and heterogeneity of the material. By using the theoretical formula Compared with the experimental data Weibull theory, the results show that the theoretical formula of this hypothesis has good accuracy in describing the strength-size effect of materials and can easily explain why the size effect disappears when the size of the specimen is large to a certain degree. The stress will be released from the boundary surface of the specimen, which is called the boundary effect of internal stress. The larger the specimen size is, the smaller the boundary surface is. Therefore, the internal stress field or internal stress can increase with the specimen size. The boundary effect causes the material strength index to decrease as the specimen size increases, and it also causes the size effect of the initial tangent modulus of the material to increase with the size of the specimen