摘要
基于理论分析、数值计算和试验测试,探讨了在正常使用状态下,张角可变的人字梯在受到不同静止载荷状态下的多类别应力分布规律,研究了当可变张角维持不变时,在量值相同但作用位置不同的静载作用下,人字梯踏板所产生的不同类别应变的变化规律。首先采用有限元分析方法初步计算了人字梯在试验设计载荷作用下的整体响应,继而采用理论计算方法计算了人字梯踏板的受力、应力和位移变形情况,以及安全使用人字梯的最大半张角,并在此基础上确定了试验方案并进行相关理论计算。得到了各类应变的最大值与两个等量载荷作用位置的函数公式,该公式属于经验公式,在工程实用中可用于进行对人字梯的安全评估和校核。
Based on theoretical analysis,numerical computation and experimental analysis,the multi-category stress distribution of civil ladder under different kinds of static load was studied,and the target ladder in normal state of use was with modifiable opening angles. The research focused on different classes of strain of a civil ladder under two static loads which were of the same value but different locations when the modifiable opening angle was left unchanged. The paper firstly studied the overall response of the civil ladder under designed loads through finite element analysis,and then,the force conditions,stress conditions,displacement conditions and deformation conditions of the footboard of the civil ladder,as well as the maximum half opening angle of safe use were studied through theoretical calculations. Based on them,the experimental design and the corresponding numerical calculation were confirmed. The conclusion comes from comparing the actual experimental result and calculation result. Apart from this,considering the actual situation,the paper resulted with a function formula between the maximum strain of each kind and the location of the two loads through polynomial fitting,which is an empirical formula. According to the formula,we can make security assessment and checking through practical applications.
出处
《实验室研究与探索》
CAS
北大核心
2015年第9期8-15,共8页
Research and Exploration In Laboratory
基金
国家自然科学基金项目(11102107)资助
关键词
人字梯
静止载荷
数值计算
应力分布
安全评估
herringbone ladders
static loads
numerical computation
stress distribution
security assessment
