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上期已讲了三个问题,这里再接着讲六个问题。一、虎克定律计算变形在弹性范围内,杆件的线变形△l与杆长l、外力P、横截面面积A之间存在着一定关系,即△l=P l/E A=N l/E A式中E为材料的弹性模量。关系式称虎克定律。我们常直接用虎克定律来计算杆件的变形。初学者容易出现的错误有下例中所讲的。例、直杆截面积为A,受荷截作用如图4所示,若P_1=P_2=P-3=P_4=P,试计算杆件的纵向线变形及线应变。
Three issues have been discussed in the previous issue, and six more issues are followed here. One, Hooke’s law to calculate the deformation in the elastic range, the rod of the line deformation △ l and rod length l, external force P, cross-sectional area A there is a certain relationship, that is △ l = P l / EA = N l / In EA, E is the elastic modulus of the material. The relationship is called Hooke’s law. We often use Hooke’s law directly to calculate the deformation of the rod. Beginners are prone to mistakes as mentioned in the following example. For example, the cross-sectional area of the straight rod is A, and the load-cutting effect is shown in Fig. 4. If P_1=P_2=P-3=P_4=P, calculate the longitudinal deformation and the linear strain of the rod.