Currey J D
Department of Biology, University of York, York YO10 5YW, UK.
J Exp Biol. 1999 Sep;202(Pt 18):2495-503. doi: 10.1242/jeb.202.18.2495.
The bending strength of a wide variety of bony types is shown to be nearly linearly proportional to Young's modulus of elasticity/100. A somewhat closer and more satisfactory fit is obtained if account is taken of the variation of yield strain with Young's modulus. This finding strongly suggests that bending strength is determined by the yield strain. The yield stress in tension, which might be expected to predict the bending strength, underestimates the true bending strength by approximately 40 %. This may be explained by two phenomena. (1) The post-yield deformation of the bone material allows a greater bending moment to be exerted after the yield point has been reached, thereby increasing the strength as calculated from beam formulae. (2) Loading in bending results in a much smaller proportion of the volume of the specimens being raised to high stresses than is the case in tension, and this reduces the likelihood of a weak part of the specimen being loaded to failure.
多种骨质类型的抗弯强度与杨氏弹性模量/100几乎呈线性比例关系。如果考虑屈服应变随杨氏模量的变化，能得到更紧密、更令人满意的拟合。这一发现有力地表明抗弯强度由屈服应变决定。拉伸时的屈服应力本应能预测抗弯强度，却比实际抗弯强度低约40%。这可能由两种现象解释。(1) 骨质材料的屈服后变形使得在达到屈服点后能施加更大的弯矩，从而根据梁公式计算出的强度增加。(2) 弯曲加载时，与拉伸情况相比，试样中承受高应力的体积比例要小得多，这降低了试样薄弱部分因加载而破坏的可能性。
