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国家标准《预应力筋用锚具、夹具和连接器》GB/T 14370-2007及与欧美标准的比较 被引量:1
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作者 裴彇 《预应力技术》 2008年第4期3-9,23,共8页
本文介绍了国家标准《预应力筋用锚具、夹具和连接点》GB/T14370-2007,并与相关标准FIP1993年"建议"、欧洲标准EN13391和美国PTI《后张预应力体系验收标准》(1998)做了概况比较。
关键词 预应力筋 锚具 夹具 连接器 锚具效率系数 预应力筋效率系数 预应力筋断时的总应变锚固
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Stretch rate and deformation for pre-stretching aluminum alloy sheet 被引量:1
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作者 朱才朝 罗家元 《Journal of Central South University》 SCIE EI CAS 2012年第4期875-881,共7页
Numerical simulation combined with experimental test was carried out to analyze the pre-stretching process of the 7075 aluminum alloy sheet,from which the stress variation curves and residual stress of aluminum alloy ... Numerical simulation combined with experimental test was carried out to analyze the pre-stretching process of the 7075 aluminum alloy sheet,from which the stress variation curves and residual stress of aluminum alloy sheet in different stretch rates were obtained.The results show that the residual stress in length direction is released after unloading the stretch force,while the residual stress in width direction is released during the stretching process.The study of residual stress elimination is beneficial for optimizing stretch rate on the basis of residual stress distribution law.By comparing the variation principle of residual stress in length direction,the size range of three deformation areas and elimination percentage of residual stress were obtained.The residual stresses of clamping area and transition area are not eliminated effectively,so sawing quantity should be the sum of both the areas.The elimination rate of residual stress in even deformation area could reach 90% after choosing a proper stretch rate,which is verified by both simulation and experiment. 展开更多
关键词 residual stress stretch rate defonnation area sawing quantity
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多工况交叠隧道围岩变形规律的三维数值模拟研究
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作者 刘涛 王康云 +1 位作者 王少飞 李晓冉 《公路交通科技(应用技术版)》 CAS CSCD 北大核心 2020年第11期275-279,共5页
为了分析交叠隧道不同夹角及不同上下叠夹岩厚度时,后建隧道开挖对既有隧道的影响,通过多种工况的三维有限元模拟分析,得到不同工况的位移、应力及张拉应变扰动区的演变规律,结果表明:交叠角度对于隧道围岩的应力与位移影响有限,但两隧... 为了分析交叠隧道不同夹角及不同上下叠夹岩厚度时,后建隧道开挖对既有隧道的影响,通过多种工况的三维有限元模拟分析,得到不同工况的位移、应力及张拉应变扰动区的演变规律,结果表明:交叠角度对于隧道围岩的应力与位移影响有限,但两隧道交叠区的应力状态与张拉应变扰动区改变较明显;当上下叠隧道的夹岩厚从0.75倍的隧道直径减少到0.5倍的隧道直径后,隧道拱顶的沉降值较大幅度降低,同时张拉应变扰动区的范围明显扩大。 展开更多
关键词 交叠隧道 有限元 交叠角 上下叠间距 拉应变区
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