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HIGH SCHOOL

Engineering

Concept Videos

Mechanical Engineering

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Bending

Composite Beam Stress and Neutral Axis

Description

Composite beam stress depends on the elastic properties of each material in the member. When a structural member is made of two materials with the same cross-sectional area, each material responds differently under load because its modulus of elasticity is different. To analyze this behavior, engineers use the transformed se...

Transcript

考虑一个由两种不同材料构成且具有相同横截面积的构件。该构件的应力方程可分别用各段的弹性模量来表示。

该构件两个不同段内的正应变沿中性轴距离呈线性变化。

通过写出作用在构件各段面积微元上的力的表达式,并将弹性模量之比定义为常数,可估算其抗弯能力。

此处,作用在构件一个段落上的力可以通过乘以两种材料弹性模量之比,来表示为作用在另一构件上的力。

如果弹性模量之比大于1,则模量较低材料的等效面积会增加;如果该比值小于1,则等效面积会减小。这种变换沿中性轴方向平行进行,所得的等效横截面称为变换截面。