圆形薄板的温度分布及热变形

为了搞清圆锯片锯切工作时的受热变形情况和热变形与圆锯片适张的关系 ,该文测量了过度适张、不开径向槽薄圆盘的受热变形情况 .在一定的转速下 ,对圆盘的外边缘模拟加热 ,通过实验研究圆盘发生热变形的机理和变形过程 .实验结果表明 :①模拟切削加工过程对圆盘的外边缘加热 ,开始阶段 ,盘的变形很小 ,维持原有的碟形状态 ,随着温度差的不断增大 ,圆盘内产生了热应力 ,当温度差达到 16℃以后 ,圆盘开始从碟形逐渐向平面转变 .②圆盘变成平面状态后 ,仍处于临界不稳定状态 ,随着温度差的继续增大 ,圆盘逐渐回复到初始的碟形状态 .③圆盘回复到初始的碟形状态之后 ,圆盘不能蓄积更多的热应力 ,发生热应力释放 .④热压曲发生后 ,温度差继续增加 ,热压曲的变形量增加不大或几乎不增加 .⑤在温度差较小时 ,适张造成的碟形变形不能变成平面状态 ,可以认为是圆盘内的残余应力或适张应力对圆盘外缘的拉紧作用抵抗着热应力 ,这就是适张的意义和作用

Temperature distribution and thermal deflection of a circular thin plate

The over-tensioned thin circular plate without slits at the edge was measured i n this pap er in order to study the thermal deflection mechanism and the process of the cir cular saw s when it rotated and was heated. The results were as follows: ①the deflect ion of the circular plate was smaller and kept the “dishing" shape at the beginning when the circular plate was heated simulating the cuttin g process at the edge. The thermal stress increased and the circular plate gradu ally turned to plane from the “dishing" shape with the increase of temperatu re difference; ②the circular plate remained in the critical instability although it was in the plane status. Then the circular plate gradually reverted to the “dishing" shape with the continuous increase of temperature difference;③the thermal stress released when the circ ular plate gradually reverted to the “dishing" shape;④the thermal deflectio n increased little or kept invariable with the continuous increase of temper ature difference after the thermal buckle has occurred;⑤the “dishing" def lection could not shift to plane when the temperature difference was insufficien t, because the tensioning stresses counteract to the thermal stresses.