意画应 §5-1引言 M 1、弯曲构件横截面上的(内力)应力 剪力Q一剪应力τ 内力 弯矩M→正应力
§5－１ 引言 1、弯曲构件横截面上的（内力）应力 内力 剪力Q 剪应力t 弯矩M 正应力s
STRESSESINBENDING 2、 Study method There are only normal stresses in the section under plane bending-beam of pure bending (There is only M and no Q in the cross section) There are shearing stresses in the section under plane bending-beam of transverse bending. (There areQ and m in the cross section) Such as: P Longitudinal plane of symmetr
There are only normal stresses in the section under plane bending beam of pure bending (There is only M and no Q in the cross section). There are shearing stresses in the section under plane bending beam of transverse bending. (There are Q and M in the cross section). 2、Study method Longitudinal plane of symmetry Such as： P1 P2
意画应 2、研究方法 平面弯曲时横截面σ→纯弯曲梁(横截面上只有M而无Q的情况) 平面弯曲时横截面τ一~剪切弯曲(横截面上既有Q又有M的情况) 例如: P 纵向对称面
平面弯曲时横截面s 纯弯曲梁(横截面上只有M而无Q的情况) 平面弯曲时横截面t 剪切弯曲(横截面上既有Q又有M的情况) 2、研究方法 纵向对称面 例如： P1 P2
STRESSESINBENDING P Pure bending: A B Deformation of some portion of the ●● beam in which there are only bending moment and no shearing stress is called 70 pure bending. Such as portion AB M、 P 纯弯变形几何关系
Deformation of some portion of the beam in which there are only bending moment and no shearing stress is called pure bending. Such as portion AB. a P P a A B Q M x x Pure Bending: P P Pa
意画应 P 纯弯曲( Pure Bending A B ●● 某段梁的内力只有弯矩 没有剪力时,该段梁的变 形称为纯弯曲。如AB段。 M、 P 纯弯变形几何关系
某段梁的内力只有弯矩 没有剪力时，该段梁的变 形称为纯弯曲。如AB段。 a P P a A B Q M x x 纯弯曲(Pure Bending): P P Pa