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许多材料力学教材中都编有温度应力的计算内容。其计算公式为:σ=α·E·△T式中σ为温度应力,α为材料的线膨胀系数,E为材料的弹性模量,△T为温升。上式是以线膨胀定律、虎克定律及拉压应力表达式为依据而导出的。值得探讨的是推导中虎克定律中的杆件长度,在国内有关教材中均引用了1,如图所示。通过教学探索与借鉴国外教材,笔者认为这种引用不够严密,会造成概念上的混乱。虎克定律式中,杆件长度指杆件受力发生变形前的长度。温度应力的形成,可看作是用外力将杆件由长(1+△1r)压缩至1所
Many material mechanics textbooks are compiled with temperature stress calculation content. The calculation formula is: σ = α · E · ΔT where σ is the temperature stress, α is the coefficient of linear expansion of the material, E is the elastic modulus of the material, and ΔT is the temperature rise. The above formula is based on the law of linear expansion, Hooke’s law and the tension and compression stress derived as a basis. Worthy of discussion is the derivation of rod length in Hooke’s law, which is quoted in the relevant textbooks in the country, as shown in the figure. Through teaching to explore and learn from foreign teaching materials, I think this reference is not tight enough, will result in conceptual confusion. Hooke’s law, the length of the rod means the length of the rod before the deformation force. The formation of temperature stress, can be seen as the external force will be the rod from the long (1 + △ 1r) compression to 1