摘要
由于材料的应变软化，或是由于薄壁梁在挠曲变形时的截面畸变，梁的弯矩一曲率关系可能呈现先强化后软化的性态。近几年来北京大学一个研究组的工作证实，具有软化特性的半无限长梁在自由端受常速度冲击时，软化可能发展为一个有限长的区段，并在梁内移动，同时，英国ＵＭＩＳＴ的一个研究组以核电站中的管道甩动问题为工程背景，集中研究了具有软化特性的有限长梁的动力行为。提出了计及弹性、强化、软化和梁的几何大变形的理论模型，并发展了相应的有限差分程序。这一理论模型能够预报软化区的萌生、发展和局部化，同管道甩动实验观测极为符合。
Due to thstrain-softening of materials or due to the cross-sectional distortion of thin-walled beams in their large deflection,the moment-curvature relation of beams may display a hardening-softening characteristic.The recent work carried out by a research groupin Peking University has confirmed that when a semi-infinite beam with softening property is subjected to a suddenly applid constant velocity at its tip,softening may develop into asegment of finite length and travel along the beam. Meanwhile,in order to study pipe-whipphenomenon in nuclear plants,a research group in UMIST,UK,has made a thorough studyon the dvnamic behaviour of beams of finite length with hardening-softening characteris-tic. A theoretical model has been proposed to incorporate an elastic-hardening-softeningmoment-curvature relat ion into a large deflect ion dynamic analysis,and a correspondingfinite-difference programme has been developed.This theory can predict the initiation,de-velopment and localization of the softening region in the dynamically loaded beams,with avery good agreement with the experimental observation of pipe-whip tests.
出处
《力学学报》
EI
CSCD
北大核心
1995年第2期161-172,共12页
Chinese Journal of Theoretical and Applied Mechanics
基金
中国国家自然科学基金委员会和英国科学与工程研究委员会(SERC)的资助
关键词
软化梁
动力学
变形
工程结构
softening beam,pipe-whip phenomenon,dynamic beliaviour
