共查询到20条相似文献,搜索用时 156 毫秒
1.
2.
船体有限元模型普遍采用板壳(shell)单元离散,而某些大厚度局部结构形状复杂,需采用实体(solid)单元模拟.在Patran软件中,对这2种单元进行简单的节点耦合会出现自由度不匹配的问题,进而导致求解错误,故对这2种单元的连接技术进行研究尤为必要.对变厚度对接平板进行全solid单元建模计算,通过与文献结果相对比,验证数值模拟的正确性;引入复合单元法、MPC-RSCCON和MPC-Rigid 3种连接技术,在不同载荷作用下对比分析结构响应;对各连接技术中的相关控制参数进行敏感性分析.结果 表明,3种方法在特定条件下均能较好地实现有限元模型中shell单元与solid单元的合理连接,其中MPC-Rigid的精度更高、操作更为方便,建议在船体结构有限元建模中采用MPC-Rigid进行shell单元与solid单元的连接. 相似文献
3.
4.
5.
根据流体力学和数值传热的基本原理,用CFX软件对某典型舰船动力舱室大气环境进行仿真研究,对仿真的对象从仿真的方法、过程、评估等方面作出初步研究,并将实船试验数据与仿真结果进行对比分析.通过仿真、对比分析表明,CFX软件可以实现舰船舱室大气环境的计算机辅助设计并对其流场分布进行优化. 相似文献
6.
结合有限元分析软件ANSYS对大潜深、大开口观察窗壳体结构模型的静态力学性能进行了数值分析及试验研究。计算模型考虑了材料非线性、几何非线性的影响。球壳采用面单元建模,观察窗窗座采用体单元建模,减少了计算规模,节省了计算时间。针对这2种不同自由度单元的连接,采用了不同的面体单元耦合技术,讨论了它们对静态力学性能结果的影响,在此基础上进行了试验研究。试验表明,本文所建立的有限元模型和计算策略准确可靠,可供设计时使用。同时也表明了在数值计算中采用MPC接触方法的面体单元耦合技术精度更高。 相似文献
7.
大型补给舰船液舱晃荡载荷计算方法 总被引:5,自引:0,他引:5
随着补给舰船的大型化,补给舰船中的液舱晃荡问题开始凸显。为给大型补给舰船的液舱结构设计提供方便、可靠的晃荡载荷输入,基于改进的VOF法,以Youngs法重构自由液面,结合部分单元参数概念,提出了一种精度更高且数值稳定的、处理非矩形复杂舱室边界晃荡载荷的计算方法。通过对不同装载情况的液舱晃荡进行数值分析,并与Hirt-Nichols算法以及实验结果进行对比,证明该方法可有效改进自由表面的模拟效果,提高舱室内部速度、加速度和压力的预报精度。网格敏感性分析证明该方法的数值稳定性较好,较粗的网格也能达到较高的精度。所建立的晃荡载荷计算方法可用于对补给舰船的液舱晃荡设计载荷进行快速、准确的预报。 相似文献
8.
[目的]针对内嵌二维声学黑洞薄板的数值模拟方法进行对比研究,[方法]提出使用板壳单元对声学黑洞薄板进行离散建模的方法。首先,设计内嵌二维声学黑洞薄板算例,应用体单元建立该薄板的有限元模型,以验证其声学黑洞效应。然后,采用相同尺度的板壳单元来模拟该二维声学黑洞薄板,并对2种建模方法的模态和振动特性进行数值对比验证。最后,讨论声学黑洞区域厚度阶梯变化尺度以及幂律对整体结构振动特性的影响。[结果]研究表明,使用板壳单元离散内嵌声学黑洞薄板计算其振动特性的精度是可靠的,板壳单元离散方法相比体单元离散法具有计算规模小、计算效率高的优点。同时,合理调节声学黑洞区域的厚度阶梯变化尺度以及幂律会改变局部模态对应的固有频率。[结论]研究结果可为声学黑洞结构的设计与应用提供指导。 相似文献
9.
10.
11.
固支方形板在水下爆炸冲击波载荷作用下动态响应数值仿真研究 总被引:2,自引:0,他引:2
舰船在实际海战中的抗打击能力是舰船生命力的重要指标.板格是舰船结构的基本组成单元,为了研究板格在爆炸载荷作用下的承载能力,采用数值方法研究了正方形板在水下爆炸冲击波载荷作用下的动态响应,分析了板的变形模式,研究了板厚和爆炸冲击因子对板的最大变形绕度的影响,推导出简单适用的经验公式. 相似文献
12.
Sandwich plate systems (SPS) are advanced materials that have begun to receive extensive attention in naval architecture and
ocean engineering. At present, according to the rules of classification societies, a mixture of shell and solid elements are
required to simulate an SPS. Based on the principle of stiffness decomposition, a new numerical simulation method for shell
elements was proposed. In accordance with the principle of stiffness decomposition, the total stiffness can be decomposed
into the bending stiffness and shear stiffness. Displacement and stress response related to bending stiffness was calculated
with the laminated shell element. Displacement and stress response due to shear was calculated by use of a computational code
write by FORTRAN language. Then the total displacement and stress response for the SPS was obtained by adding together these
two parts of total displacement and stress. Finally, a rectangular SPS plate and a double-bottom structure were used for a
simulation. The results show that the deflection simulated by the elements proposed in the paper is larger than the same simulated
by solid elements and the analytical solution according to Hoff theory and approximate to the same simulated by the mixture
of shell-solid elements, and the stress simulated by the elements proposed in the paper is approximate to the other simulating
methods. So compared with calculations based on a mixture of shell and solid elements, the numerical simulation method given
in the paper is more efficient and easier to do. 相似文献
13.
14.
由于具有高强度、高模量、重量轻、耐腐蚀的优良特点,复合材料在船舶上的应用逐渐成为研究热点.目前可查阅的关于船体复合材料结构强度校核的文献很罕见以及各种规范对船体复合材料结构强度校核尚未给出明确的说明.与各向同性材料的强度评估方法相比,复合材料强度评估有很大的不同.本文基于试验结果,分别采用壳单元、实体-壳单元和实体单元模型对复合材料结构进行数值分析,确定用于轻质夹芯复合材料结构强度评估的合理有限元模型.基于渐进损伤分析理论,采用Tsai-Wu失效准则和突降退化模型,对轻质夹芯复合材料的极限强度进行评估.结果表明:计及结果精确性与计算成本,可用壳单元模型分析复合材料结构的应力-应变分布;渐进损伤分析方法结合材料退化模型不仅有效地对复合材料结构的极限强度进行预测,同时还能判断材料的失效模式. 相似文献
15.
针对一种新型海港活动式防浪结构,基于有限元法建立4种分析模型进行模拟计算。对比分析可知,利用接触面上节点自由度耦合方式创建的有限元模型更适用。运用上述有限元模型,分别对活动式防浪结构的应力、位移和螺栓内力进行求解,以及分析钢材厚度变化对组合结构力学性能的影响。结果表明:钢构件下端拉、压应力较大,需重点加强;板厚越小,组合结构的应力和变形越敏感。结合防浪结构的安全性和经济性,提出设计和优化要点,为工程应用提供参考。 相似文献
16.
对2块厚度为24mm的Ti-6Al-4VELI厚板进行夹角为171.98°的多层TIG焊接试验,基于SYSWELD软件平台,在焊板两端完全刚性固定的装夹条件下数值模拟计算焊接温度场、应力场和焊接引起的变形.计算结果表明,焊接温度场的变化规律符合实际,焊缝区的拉伸残余应力最大,热影响区的压缩残余应力较大.焊接数值模拟得到的残余应力场与试验测量值能较好地吻合,验证了数值模拟模型的准确性.该数值模拟方法可应用到大深度Ti-6Al-4VELI载人舱强度计算中的焊缝残余应力模拟中. 相似文献
17.
《Marine Structures》2004,17(1):1-27
This paper presents a combined experimental–numerical procedure for development and calibration of macroscopic crack propagation criteria in large-scale shell structures. A novel experimental set-up is described in which a mode-I crack can be driven 400 mm through a 20(+) mm thick plate under fully plastic and controlled conditions. The test specimen can be deformed either in combined in-plane bending and extension or in pure extension. Experimental results are described for 5 and 10 mm thick aluminium and steel plates. By performing an inverse finite-element analysis of the experimental results where the simulated crack growth is forced to correspond to the experimental observations, empirical criteria for ductile crack propagation emerge very clearly. Using the experiments with edge crack specimens (ECS) in combined in-plane bending and extension, crack propagation criteria are developed for steel and aluminium plates, mainly as curves showing the critical element deformation versus the shell element size. These derived crack propagation criteria are then validated against a separate set of experiments considering centre crack specimens (CCS) which have a different crack-tip constraint. The applicability of the often-used equivalent strain criterion is discussed versus a more rationally based criterion which takes into account the stress tri-axiality. A large-scale grounding experiment is also simulated showing very good agreement with measurements. The performance of the proposed model is in general good and it is believed that the presented results and experimental–numerical calibration procedure can be of use in practical finite-element simulations of collision and grounding events with the use of shell elements. As discussed, the paper provides a clean framework for further development of macroscopic crack propagation criteria in large-scale plate structures. 相似文献
18.
For the evaluation of the structural response in accidental scenarios like ship collisions, the simulation of tensile failure initiation is inevitable. Here, one difficulty is that the process of failure initiation is a very local process, which cannot be simulated in its details at present due to the computing effort which would be required. However, there are various approaches how the failure initiation can be simplified and simulated in finite element models of large thin-walled structures. A short overview of these approaches is given. A pragmatic approach, which is suitable for relatively small elements for the simulation of failure initiation in uniaxial to biaxial stress states, is chosen within this paper for further investigations regarding the applicability for thin-walled steel structures. Exemplary simulations with solid and, in particular, shell elements are used to demonstrate how the effects of element size and other element properties can be considered in the simulation of failure initiation. The focus is also on imperfections that are relevant in simulations with small elements. For this purpose, an indentation experiment is simulated with different imperfections. 相似文献
19.
20.
结合港珠澳大桥岛隧工程东人工岛工程实例,基于 PLAXIS 3D 有限元软件计算平台,利用可同时考虑剪切硬化和压缩硬化的土体弹塑性本构模型 Hardening-soil model,对深插式大直径钢圆筒岛壁结构三维数值计算展开研究,分析施工全过程中各控制工况下钢圆筒的变位情况,并与二维理论计算和现场实测位移相验证,探讨深厚软黏土地基上大圆筒结构的变形与稳定特性。结果表明,三维数值模拟钢圆筒位移和实测位移相近,两者均大于二维平面等效计算位移值;当钢圆筒有足够的直径和埋深时,即使其插入深厚软黏土地基,水平和竖向变位均较大,但是其结构稳定性也较好。分析成果对类似工程以及大直径钢圆筒结构在软土地基上的推广应用具有一定的参考意义。 相似文献