南海某油田防沉板极限承载力研究

防沉板是水下生产系统常用的基础结构之一,其极限承载力是影响上部结构安全稳定的重要因素。为解决南海油田防沉板的极限承载力计算问题,依托南海某油田水下生产系统,根据API规范,计算了防沉板在实际工况下的极限承载力; 采用Abaqus有限元软件,建立土体和防沉板的有限元模型,在对土体进行地应力平衡的基础上,采用位移控制法,得到了防沉板的载荷-位移曲线,据此得到防沉板基础的极限承载力,并分析土体在竖向位移下的破坏规律; 将依据API规范计算的极限承载力与有限元仿真结果进行对比,显示两者相差1.23%。研究成果对防沉板的稳定性评估具有一定的指导意义。     

盘式制动器的温度场及应力场分析

随着我国经济水平的提高,汽车工业逐步发达,车辆的保有量不断增加,造成交通事故的频频发生,因此汽车的安全性越来越受到人们的重视。汽车制动器由温度产生的疲劳破坏是事故频发的诱因之一。通过有限元软件Abaqus对模拟结果分析得到制动器制动过程中温度及应力分布规律,最后通过改变有限元模型及边界条件并进行对比分析得到制动盘温度的升高是产生高热应力的最主要因素且制动盘尺寸对热应力分布有着重要影响,这也为制动器结构的设计和改进及摩擦片材料的选取及研制提供了参考和理论依据。     

液硫池破损原因分析及改进措施研究

在实际生产中,硫磺通常以液态形式进行储存运输。液硫池作为储存液体硫磺的重要设施,由于储存介质的特殊性,其铸造和设计与普通水池相比有更高的要求,如果设计不合适,可能会造成液硫池的破损。首先,简要介绍了某天然气净化厂液硫池的设计特点,并针对其曾出现的破损问题,分析发生破损的原因;然后,借助abaqus有限元分析软件对液硫池进行温度场模拟。模拟结果显示,混凝土层的温度超过100℃,通过模拟液硫池的受力变形,得出高温环境是液硫池发生破损的诱因;最后,在混凝土层温度控制、选材以及操作优化等方面提出了一定的修改意见。     

Numerical simulation of the transient hydrogen trapping process using an analytical approximation of the McNabb and Foster equation. Part 2: Domain of validity

In a previous study [1], a resolution scheme called Generalized Oriani's Approximation (GOA) was proposed to solve a transient transport and trapping problem in the Abaqus Finite Element software. This proposition was motivated by the convergence of the Finite Element problem linked to the estimation of several functions during the computation (and especially the dudt one). In this study, the GOA is shown to be able to provide an accurate estimation of the trapped concentration in transient trapping processes as soon as the time increment is small enough for two configurations: hydrogen in metals and water in polymers. An estimation of the induced error is given. The GOA approach is illustrated on a simple configuration with various trapping parameters. Last, the ability of Abaqus to converge while modeling a transient trapping and transport problem is analyzed considering several dudt: it is shown especially that its estimation based on the GOA allows the solver to efficiently converge toward the solution.     

注聚平台振动特性及阻尼基座隔振性能

基于Abaqus软件建立大型注聚泵作用下注聚平台动力响应分析模型,探究注聚泵布置方式、开启数量、启动间隔等参数对注聚平台振动特性的影响规律。基于被动隔振原理提出一种迷宫式约束阻尼隔振基座用于降低平台的振动,并采用数值方法对该约束阻尼隔振基座的隔振效率进行研究。结果表明,注聚平台的振动响应会随着注聚泵开启数量的增加呈现线性增长趋势,不同启动间隔可导致注聚泵机振动载荷相互抵消,从而导致注聚平台振动响应大幅降低,而迷宫式约束阻尼隔振基座可显著降低注聚平台多个自由度的振动响应,其隔振效率可达20%。     

海上风电吸力桶结构分析

针对实际工程条件,创新性地设计一种全新吸力筒形式,并借助SACS软件构建综合考虑土壤影响的吸力筒导管架风机模型。在极端工况下,详细分析该结构的性能。结果表明,在外部极端载荷作用下,导管架结构可满足工程要求,确保结构的整体稳定。采用Abaqus软件对过渡段和吸力筒部分强度进行精确校核,计算结果表明两者的强度均满足设计和使用需求,具备足够的承载潜力和稳定性。分析表明新设计的吸力筒在复杂工程背景下表现出色,为类似工程的设计与优化提供了可靠参考依据,同时也丰富海上风电吸力桶基础的研究与实践。     

预制桥面板 ＵＨＰＣ湿接缝的界面受力性能研究

为确定合理的界面间约束与接触关系,采用ＡＢＡＱＵＳ中3种不同的约束与接触关系基于现有试验试件进行模拟,将数值分析结果与试验结果与进行对比分析。研究表明:采用内聚力模型的有限元模型破坏形态与试验结果较为一致,绑定约束次之,而采用接触摩擦模型的有限元模拟结果与试验差别最大;以试验开裂荷载与极限荷载为分析对象,绑定约束与内聚力模型的数值分析结果与试验吻合较好,而接触摩擦模型的数值分析结果与试验差异较大;与绑定约束模型相比,内聚力模型能够较好地模拟试件界面的损伤。因此,当采用ＡＢＡＱＵＳ进行预制桥面板与ＵＨＰＣ湿接缝的界面受力的有限元分析时,宜采用内聚力模型或绑定约束模型,不宜采用接触摩擦模型。     

高频振动打桩对邻近基桩影响分析

为解决在城市里桩基施工引起的环境问题,国外开发并推广应用了高频液压振动锤技术。通过有限元软件Abaqus对高频振动打桩对邻近桩基影响进行模拟。模拟中桩轴线处建立半径为1mm的管,管土接触设为光滑,打桩时土管分离,桩随着管向下贯入,形成打入桩和周围土体之间的接触关系。打入桩和圆管采用刚体模拟,土体单元则采用摩尔库伦本构模型,建立高频打桩的三维模型,很好的实现高频液压振动沉桩整个过程的数值分析。贯入模拟过程表明打入桩桩尖深度处有应力集中现象;离打入桩越远,受到的影响越小。且分析表明高频振动打桩对邻近桩基的影响很小。     

汽车传动轴压装工艺分析

在对比汽车传动轴传统单端压装和两端压装的基础上,使用有限元软件Abaqus对汽车传动轴过盈压装进行有限元模拟仿真,通过分析不同工艺参数如过盈量、轴管长度、不同过盈组合形式等对传动轴支反力RF,轴管径向塑变U1和轴向应力S33的影响,对传动轴压装工艺进行论证。     

Moisture-induced stresses perpendicular to grain in cross-sections of timber members exposed to different climates

In variable humidity conditions, wood absorbs or desorbs moisture from the air. Unless the change in humidity is very slow, this will develop moisture gradients in the wood sections. These gradients will develop stresses due to constrained swelling or shrinkage strains. These stresses are named moisture-induced stresses. The present paper investigates the main parameters affecting such moisture-induced stresses, including the type of climate, the size of the timber cross-section, and the type of protective coating. A first attempt to identify moisture-induced stresses in different European climatic regions was made. For each climatic region, relative humidity and temperature histories were identified, and characteristic and mean values of yearly and daily variations were calculated. Using a finite element model implemented in Abaqus, the moisture content and stress distribution were computed on different timber cross-sections exposed to the climatic regions and protected with different types of coating. A Fickian moisture transfer model was used to compute the moisture distribution, and a mechanical model for time-dependent behaviour of wood was implemented to calculate the corresponding stress distribution. The variation of moisture was found to result in stresses of magnitudes that would probably cause cracking of wood in the perimeter of any uncoated cross-section size. The use of a protective coating, however, reduced considerably the moisture-induced stresses, and can be regarded as an effective protective measure to avoid cracking due to humidity variations. Considering European climates, Northern climates were found to result in higher surface tensile stresses than Southern climates.