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Energy Absorption Abilities of Members by Dynamic Loading

动载荷下构件的能量吸收能力

基本信息

批准号：
08045031
负责人：
UJIHASHI Sadayuki
金额：
$ 1.73万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08045031/
关键词：
Thin-Walled Member Impact Crushing Energy Absorption Drop Weight Test Composite Material Measurement System Temperature Dependency Scaling Law

项目摘要

In the present research, a theoretical mechanism analysis based on plastic hinge models with perfect plastic material properties is suggested in order to estimate the energy absorption abilities of thin-walled circular and square tubes by axial crushing under impact loading. The relationship between dynamic bending moments and angular velocities measured in our previous research is employed instead of the constitutive equations obtained from tensile tests because the main energy absorption in thin-walled tubes occurs by bending work at plastic hinges. On the basis of this procedure, the time histories of the deformation and the absorbed energy can be calculated with good agreement with the experimental results. Crushing periods could not be determined theoretically in the case of square tubes, but were determined in the case of circular tubes. In addition, the axial crushing of thin-welled tubes was carried out successfully taking into account the dynamic relationship between perfect plastic bending moments and bending angular velocities in plastics hinges.On the other hand, the energy-absorption abilities of thin-walled circular cylinders made from carbon-fiber-reinforced plastic (CFRP) during crushing under impact loading. The tests are carried out with an impact testing machine, the crosshead mass of which is 21.5kg, at a velocity of 8ms-1 under the temperature range 20 to 130ﾟC The ply angles of the specimens are 15 and 75ﾟ, their dimension are 1.2mm in thickness, 30mm in inner diameter and 100mm in length. Load-time and displacement-time profiles are converted to the force and deformation relationship, which manifests the energy-adsorption abilities. The specimens produce two different types of crushing mode and definite constant load levels which keep their energy-absorption ability high. The energy-absorption abilities and the crushing modes of the specimens change at temperatures above60ﾟC.

在本研究中，建议的理论机制分析的基础上塑性铰模型与理想的塑性材料性能，以估计薄壁圆管和方管的冲击载荷下的轴向破碎的能量吸收能力。在我们以前的研究中测得的动态弯曲力矩和角速度之间的关系，而不是从拉伸试验中得到的本构方程，因为在薄壁管的主要能量吸收发生在塑性铰弯曲功。在此基础上，计算了变形和吸收能量的时间历程，与实验结果吻合较好。在方管的情况下，不能从理论上确定压碎周期，但在圆管的情况下，可以确定压碎周期。此外，考虑到理想塑性弯矩与塑性铰中弯曲角速度之间的动力学关系，以及碳纤维增强塑料（CFRP）薄壁圆筒在冲击载荷作用下破碎时的能量吸收能力，成功地实现了薄壁圆筒的轴向破碎。试验在21.5kg十字头冲击试验机上进行，速度为8 ms ~（-1），温度范围为20 ~ 130 ℃。试件铺层角为15 °和75 °，厚度为1.2mm，内径为30 mm，长度为100 mm。将载荷-时间曲线和位移-时间曲线转换为力和变形关系，反映了能量吸收能力。试件产生两种不同类型的破碎模式和确定的恒定载荷水平，保持其高的能量吸收能力。当温度高于60 ℃时，试样的能量吸收能力和破碎模式发生变化。