FPSO典型焊接接头残余应力释放及其对疲劳强度的影响

为了在估算结构疲劳强度时计及残余应力释放的作用,合理地解释在以往焊接接头疲劳试验中不能解释的试验结果,借助三维弹塑性有限元法,研究了FPSO典型焊接接头在任意变幅循环载荷作用下的残余应力释放规律,建立了在任意变幅循环载荷作用下残余应力释放大小与残余应力和外载荷大小之间的计算公式,从而定量地分析了残余应力的释放,提高了疲劳强度估算的准确性和可靠性。     

频率变化对连杆动态应力的影响研究

通过试验研究验证了连杆有限元仿真模型的精确性,进一步研究了加载频率变化对连杆动态应力的影响,得到了加载频率变化对连杆动态应力的影响规律.结果表明:在加载频率较低时,连杆动态应力会随着加载频率的增加而增大,但总体来说应力值增加不大,可以忽略;在加载频率较高时,加载频率对连杆动态应力的影响很大,不可忽略.     

Dynamic anti-plane interaction between an impermeable crack and a circular cavity in an infinite piezoelectric medium

Wave propagation in an infinite elastic piezoelectric medium with a circular cavity and an impermeable crack subjected to steady-state anti-plane shearing was studied based on Green＇s function and the crack-division technique. Theoretical solutions were derived for the whole elastic displacement and electric potential field in the interaction between the circular cavity and the impermeable crack. Expressions were obtained on the dynamic stress concentration factor （DSCF） at the cavity＇s edge, the dynamic stress intensity factor （DSIF） and the dynamic electric displacement intensity factor （DEDIF） at the crack tip. Numerical solutions were performed and plotted with different incident wave numbers, parameters of piezoelectric materials and geometries of the structure. Finally, some of the calculation results were compared with the case of dynamic anti-plane interaction of a permeable crack and a circular cavity in an infinite piezoelectric medium. This paper can provide a valuable reference for the design of piezoelectric actuators and sensors widely used in marine structures.     

斜拉桥双边箱主梁空间受力特性研究

针对某斜拉桥预应力混凝土双边箱主梁受力特点，应用MIDASFEA专业有限元计算程序对其空间结构受力进行分析，得出该结构的空间应力分布规律，并对类似结构的设计提出了若干建议。     

中、英、美规范温度梯度效应的分析比较

根据中、英、美3国公路桥梁相关规范介绍的方法,对常见跨度的预应力混凝土桥梁的温度梯度效应及其在组合应力中的贡献进行分析与比较.通过对比,认为中国2004规范规定的温度梯度效应较大,而且在抗裂方面要求较严格,建议对我国已建桥梁结构由于温度梯度效应造成的病害进行调查、分析,更合理地确定其分项系数.     

复杂悬跨条件下的管线涡激振动分析(英文)

Spans occur when a pipeline is laid on a rough undulating seabed or when upheaval buckling occurs due to constrained thermal expansion. This not only results in static and dynamic loads on the flowline at span sections, but also generates vortex induced vibration (VIV), which can lead to fatigue issues. The phenomenon, if not predicted and controlled properly, will negatively affect pipeline integrity, leading to expensive remediation and intervention work. Span analysis can be complicated by: long span lengths, a large number of spans caused by a rough seabed, and multi-span interactions. In addition, the complexity can be more onerous and challenging when soil uncertainty, concrete degradation and unknown residual lay tension are considered in the analysis. This paper describes the latest developments and a .state-of-the-art. finite element analysis program that has been developed to simulate the span response of a flowline under complex boundary and loading conditions. Both VIV and direct wave loading are captured in the analysis and the results are sequentially used for the ultimate limit state (ULS) check and fatigue life calculation.     

一维可压缩欧拉方程组解的爆破

在假设某些初始数据较大的条件下,研究由可压缩欧拉方程描述的多方气态理想流体.利用对称双曲型方程组解的存在性结论,将该方程组化为对称双曲型方程组,得到一维空间中可压缩欧拉方程的Cauchy问题的经典解关于时间的局部存在性;并通过构造适当的泛函,得到了其经典解在有限时间内必定发生爆破的结论.     

简支叠梁缝处应力问题分析

工程中存在着大量的叠梁问题，本文对简支叠梁进行了探索研究，从实验观察和理论分析两方面得出叠梁上下部分不产生相对滑动的原因，主要是梁上的正应力重新分布的结果。     

中孟高速公路橡胶沥青应力吸收层的技术应用

自2006年以来,宁夏新建高速公路集中采用了路面分期实施的方法,以降低路基工后沉降对路面行车安全和舒适性的影响,但在路面下面层通车后的2-3年里,路面出现了不同程度的横纵裂缝,将影响到路面行车安全和路面的使用寿命。现以中宁至孟家湾高速公路为例,探讨橡胶沥青应力吸收层的功能和应用,为现阶段和未来若干年更多的水稳类半刚性基层高速公路在路面反射裂缝的处理,提供借鉴和参考。     

碳纤维布加固混凝土矩形墩柱温度自应力探讨

基于平截面假定和自平衡力系条件,对碳纤维布(CFS)加固的任意形状横截面混凝土构件,建立日照辐射或骤然降温引起的温度自约束变形求解方程。推导CFS加固混凝土矩形墩柱在均匀变化、线性变化和指数变化温度梯度下的温度自应力解析式。与未加固混凝土矩形墩柱温度自应力解析式进行对比分析,结果表明,即使在均匀和线性变化温度梯度下,CFS加固矩形墩柱也会产生温度自应力;在指数变化温度梯度下,CFS中产生可观的温度自应力。所推导的自约束变形求解方程和温度自应力解析式具有一般性,适用于CFS加固混凝土构件和未加固混凝土构件。