Fire resistance performance on restrained high strength Q460 steel beams   总被引：2，自引：0，他引：2  

He Pingzhao  Wang Weiyong 《保鲜与加工》2015,(2):52-59

为了研究约束高强度Q460钢梁的抗火性能,在已有约束钢梁分析理论的基础上,引入残余应力,提出了约束钢梁的抗火性能分析方法,并采用普通强度约束钢梁试验数据对分析方法进行了验证。考虑高强度Q460钢材高温下力学性能参数,利用所提出的方法分析了约束高强度Q460钢梁的抗火性能,并与普通强度Q345钢梁进行了对比。对影响约束高强度Q460钢梁的抗火性能参数进行了分析,包括荷载比、残余应力、轴向约束刚度、转动约束刚度和受火方式等。研究表明：所提出的分析方法准确可靠,高强度Q460钢梁抗火性能与普通强度钢梁具有较大的区别,高强度Q460约束钢梁的抗火性能明显优于普通强度约束钢梁。荷载比、轴向约束刚度、转动约束刚度、受火方式对高强度Q460约束钢梁有较大影响。  相似文献   

Approaches to enhance power density of gearboxes for wind turbines     

LIU Zhongming 《保鲜与加工》2015,(1):133-139

Based on pitting strength, some approaches to enhance power density of gearboxes for wind turbines are discussed. The calculation load is greatly reduced by power division. Allowable stress numbers are effectively increased by improving property of quality materials, precision heat treatment or shot peening. Load capacities can be also obviously enhanced by improving the tooth shape of morphology optimization of tooth root, tooth correction or superfinishing of tooth surface. The center distance is effectively decreased by minishing minimum allowable safety factor or enlarging face width. The power density of gearbox can be further improved by means of structure optimization of planet carrier or uniform load of planetary gear transmission.  相似文献   

Effects of Stitcing on the Buckling Strength of Stitched Composite Laminates     

WEI Yu-qing~  CHEN Bin~ 《保鲜与加工》2004,(7):24-27

A theoretic model is proposed based on the mechanism of the buckling failure of the stitched composite laminates containing delaminations. The buckling strength of the stitched composite laminates under the in-plane compressive load is predicted. The critical percentage elongation of the stitching thread is taken into account as a control parameter of the buckling failure. The energy method is used to calculate the buckling strength of the stitched composite laminates, and the minimal potential energy is used to calculate that of the unstitched composite laminates. The result shows that the buckling strength of the stitched composite laminates is larger than that of the unstitched composite laminates. The effects of stitching technical parameters such as the stitch thread diameter, stitch step and stitch space on the stitched composite laminates are also analyzed.  相似文献   

Behavior and Design of High-strength Bolt in Tensile Connection     

CHENG Rui  CUI Ji  LONG Li-ping 《保鲜与加工》2002,(4):25-30

The tensile strength of high strength bolt is affected by many factors, including prying force. The prying force can result in the increment of bolt force, for which the connection failed ahead of time. Several methods are presented for calculating the prying force. In the China's "Code for Design of Steel Structure" (GB50017), there is no formula for calculation of prying force and a factor of 0.8 is considered in formula for tensile strength of bolt for taking the prying force into account. It is proposed that the design value of tensile resistance for high strength bolt should be increased.  相似文献   

Effect of Stitching on the In-plane Tensile Strength of Stitched Composite Laminates     

DENG Chuan bin  ZHANG Jun qian  LI Ping 《保鲜与加工》2002,(1):9-12

Some additional effects of stitching on the in-plane mechanical properties of composite laminate is introduced while it was used to improve the interlaminar of plane mechanical properties of the composite laminate. The paper investigates the effect of stitching on in-plane tensile strength of composite laminates. The results show that the effect of stitching is dependent on the stitching parameters. The in-plane tensile strength of laminates is degraded with the decreasing of stitching space and step and increasing diameter of stitching thread. It is found that the initial damage of laminate increased with increasing of stitching parameters such as stitching density. This causes the decrease in the in-plane strength of composite laminate.  相似文献   

A Study of Limiting Values for Minimal Ratio of Longitudinal Tensile Reinforcement in Non-seismic Reinforced Concrete Beams     

《保鲜与加工》2003,(2):37-42

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Test and Computation of Suspended Cable''s Static Tensile Force of a ''Basket Handle'' Type Arch Bridge     

《保鲜与加工》2003,(2):54

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Application OF SFRHSC IN Blast-Resistant Engineering     

JIAO Chu-jie  SUN Wei  GAO Pei-zheng  ZHOU Yun 《保鲜与加工》2007,(5):168-172

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强度参数统计特性对边坡稳定可靠性的影响     

桂勇  罗嗣海  邓通发 《保鲜与加工》2015,(4):67-76

由于对边坡强度参数统计特性考虑不全面,使得边坡可靠性指标计算值偏小,对应的失效概率偏大,常常超过10%,设计中难以采纳,造成地基可靠度规范的制定和执行进展缓慢。以某高速公路全风化花岗岩土质高边坡为工程背景,在分析土质参数统计特性的基础上,采用极限平衡理论和蒙特卡罗模拟法,系统地分析了土质强度参数的均值不定性、变异性、相关性、区间特性和空间变化性等对边坡稳定可靠性的影响。结果表明：土性参数的各种统计特性对边坡稳定可靠性均具有不同程度的影响。可靠性指标计算值随抽样距离的减小而增加,随c或φ均值的增大而增加,随c和φ的变异系数的增大而减小,随c和φ相关系数绝对值的增大而增加,考虑区间性后可靠性指标计算值也明显变大。即变异性对边坡稳定不利,而相关性、区间性和空间变化性对边坡稳定有利。因此,准确而全面地考虑土质参数的统计特性,尤其是在参数变异性和相关性的基础上加以考虑土性参数空间变化性和区间性会更加符合工程实际,且计算结果趋于安全,有利于地基可靠度规范的推广运用和边坡工程的安全评价。  相似文献   

喷雾机器人远程控制系统的设计与试验研究     

姚飚  邱白晶 《农机化研究》2007,(11):135-137,141

结合喷雾机器人作业环境的要求,开发出基于客户端/服务器模式的远程控制平台.该平台实现了通过无线网络实时传输各类数据和控制命令,客户端再现了机器人的工作环境和状态.在此基础上进行了系统性能测试和轨迹测试.试验结果表明:为了保证良好的操控性,机器人所处区域信号强度必须大于30%,操作者根据反馈信息判断机器人是否偏离预定路径,并在偏离时给予有效的纠正,为解决喷雾机器人重喷、漏喷的问题提供了一种方法.  相似文献