弯曲
弯曲（或弯曲）测试表征了细长样品的行为（一维只是其纵向的一小部分-其他两个十分之一），并且垂直于其纵轴施加了载荷。该测试配置在评估功能为支撑约束的结构元素（例如梁或骨头）时特别有用。在三点弯曲测试中，样品放置在对称放置的两个支撑杆上，长度约为样品长度的75％，而上杆施加垂直变形以使样品在底部杆之间的中心弯曲。在四点形式中，单个上杆由安装在中心枢轴点上的两个杆代替，两个杆对称地放置在样品长度的大约25％处。这种设置减少了在三点形式的加载点下观察到的应力集中，并将其分布在两个加载点之间的较大区域，避免了样品过早失效。4点弯曲测试对于非均质材料特别有用。两种弯曲测试均提供弯曲时的弹性模量和材料的弯曲应力-应变响应值。
BENDING
Bending (or flexure) tests characterize the behavior of a slender sample (one dimension being a small fraction - a tenth - of the other two) with load applied perpendicular to its longitudinal axis. This test configuration is particularly useful in evaluating a structural element whose function is to support constraints, e.g. beams or bones. In a 3-point bending test, the sample rests on two support rods placed symmetrically at approximately 75% of the sample's length, while an upper rod applies vertical deformation to bend the sample at the center between the bottom rods. In a 4-point version, the single upper rod is replaced by two rods, mounted on a central pivot point, placed symmetrically at approximately 25% of the sample's length. This setup reduces stress concentration observed under the loading point in the 3-point version and distributes it over a larger region between the two loading points, avoiding premature failure of the sample. 4-point bending tests are particularly useful for non-homogeneous materials. Both bending tests provide values for the modulus of elasticity in bending and the flexural stress-strain response of the material.
参考文献
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