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在机械设计中要尽量提高梁的弯曲强度,降低材料的消耗,从而使设计满足既安全又经济的要求,这是工程技术人员必备的基本思路。在一般情况下,梁的设计是以弯曲正应力强度条件为依据的。从弯曲正应力强度条件σmax=Mmax/Wz≤[σ]可以看出,梁的强度与外力引起的最大弯矩、横截面的形状和尺寸及所用的材料有关。因此,要提高梁的弯曲强度,一方面是采用合理的截面形状,以增大抗弯截面系数Wz的数值,充分利用材料;另一方面应合理安排梁的受力情况,以降低最大弯矩Mmax的数值。
In the mechanical design to maximize the bending strength of the beam, reducing material consumption, so that the design to meet the requirements of both safe and economical, which is the basic idea of engineering and technical personnel. Under normal circumstances, the design of the beam is based on the bending strength of the normal stress conditions. From the bending normal stress intensity condition σmax = Mmax / Wz≤ [σ], it can be seen that the strength of the beam is related to the maximum bending moment due to external force, the shape and size of the cross section and the material used. Therefore, to improve the bending strength of the beam, on the one hand, a reasonable cross-sectional shape should be adopted to increase the value of the bending moment coefficient Wz and make full use of the material; on the other hand, the beam force should be rationally arranged to reduce the maximum bending moment The value of Mmax.