The Rigid Plasticity Analysis Of Defect Cantilever Beam Suffering Step Load

Impact is a common dynamics phenomenon. In the past analysis of dynamics, the conclusions drawn from the dead load status can not be always applied to the status directly when the structure is affected by impact load. And the transformation of structure deformation model caused from impact load, can't be even explained by the analysis of dead load status.In this dissertation, selected the model-- Rigid plastics cantilever beam, and referred to the previous research, analyzing the reactivity when non-defective beam effected by step load in the first and analyzing a limitation occurred usually in the engineering practice—Rigid plastics cantilever beam with a main crack effected by step load status in the second. In the latter, it discovers that there is a quite different reactivity between defective beam and non-defective beam; the beam will be have a countermovement when effected by strong impact load, due to the existence of crack effect. In the end of the analyses part, each calculating examples are provided respectively. In the end of the dissertation, the possible directions are discussed for the further study.This dissertation introduces the usual crack phenomena to impact dynamics, refers to previous research and obtains a primary researchs which need to be approved by experiments. However, the conclusion is drawn under the premises, such as: the centralization of crack effect, and neglecting the subordinate effect. Therefore, to do the further analysis on these effects and study coupling actions would be done in the next step.