共查询到19条相似文献,搜索用时 62 毫秒
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采用理论计算与动高压实验相结合的方法,提出了一个计算剪切模量温度系数G′T的新方法.首先用理论方法计算一个中间数据G(PS),然后再与动高压实验数据G(PH)结合在一起计算出G′T,并针对93钨合金材料进行了计算.计算结果表明剪切模量温度系数G′T开始是随温度和压力变化的,但在高温高压下,它趋近于一常数.对于93钨合金,这个常数约为-004GPa/℃.同时,这也是对Steinberg本构模型中的剪切模量温度系数为常数的一个证明.并且,当把这一常数代入剪切模量温度系数的计算式中,将重新计算出的剪切模量与实验测得的剪切模量结果进行了比较,结果表明二者符合得很好,从而证明了本计算的剪切模量温度系数的正确性.
关键词:
有限应变物态方程
剪切模量温度系数
Steinberg本构模型
动高压实验 相似文献
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三维频域自由面格林函数及其偏导数的数值计算是海洋结构物水动力分析的难点.本文对有限水深格林函数及其偏导数的数值算法作出两点改进:①对原函数的级数表达式进行变形,提出适用于数值计算的形式,解决高频率情况下级数解的计算失真问题;②对Gauss-Laguerre积分法作出改进,解决高频率大水深情况下积分解的数值溢出问题.计算... 相似文献
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为探索高维多介质流体力学散乱点集上的Lagrange有限点方法,首先对相应一维问题进行研究,提出一种Lagrange有限点方法:在计算区域内(包括物质界面)设置任意离散点集,所有力学量都设在该点集上,在内点和界面点上分别建立离散格式.内点算法为基于Taylor展开的差分方法.界面点算法为显式追踪算法,从定解条件出发,利用Rankine-Hugoniot关系和特征差分方法,计算界面点位置及相应的状态量变化.通过追踪界面点的运动得到物质界面是方法的最大特色.典型算例计算结果与精确解符合很好,验证了算法的合理和有效性. 相似文献
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给定网络拓扑结构和有限添加边资源,如何优化配置添加边使重构后的网络拓扑结构具有最优可生存性是非常有价值的研究问题.本文首先明确网络可生存性的量化评估指标,以移除节点后网络结构的鲁棒性和有效性为优化目标,提出网络拓扑重构优化问题的建模与分析方法.同时在给定资源代价的约束下,为实现添加边资源配置效率的最大化,提出优先配置节点加强保护圈的启发式算法.仿真实验表明,该算法在有限资源约束的随机局部故障和选择性攻击环境中,能兼顾改善网络鲁棒性和传输效率,有效提升网络结构的可生存性. 相似文献
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使用计算流体动力学、传热学、固体弹性力学和光学的多物理场耦合集成仿真分析技术完成了红外热像仪中光机的热特性与热设计研究.采用有限单元法(Finite Element Method,FEM)和计算流体动力学(Computational Fluid Dynamics,CFD)得到了光机内部的温度场、应力变形分布及光学件面形... 相似文献
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为提高计算效率,提出有限体积法离散下的虚拟区域颗粒两相流动直接模拟方法.在控制方程中加入相应的虚拟区域源项,保证了颗粒内部的刚体运动特性.该源项中含有颗粒信息部分及流体信息部分.在每次迭代后,对源项中的流体信息部分进行更新,从而更好地保证颗粒内速度的刚体分布.计算静止颗粒圆柱绕流及单个颗粒的沉降过程,验证了算法的准确性. 相似文献
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利用有限场/PM3方法计算了以三氟甲基做为吸电子基因芪衍生物的生成热、偶极矩极化率、和一、二阶超级化率。说明这类化合物是很好的二次谐波产生侯选材料。 相似文献
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Phase-field models with conserved phase-field variables result in a 4th order evolution partial differential equation (PDE). When coupled with the usual 2nd order thermo-mechanics equations, such problems require special treatment. In the past, the finite element method (FEM) has been successfully applied to non-conserved phase fields, governed by a 2nd order PDE. For higher order equations, the convergence of the standard Galerkin FEM requires that the interpolation functions belong to a higher continuity class. 相似文献
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In this work, we propose a study dedicated to the influence of the delay line nature in transverse ultrasonic sensors, dedicated to dynamic high frequency elastic moduli of viscoelastic materials estimation. In literature, these shear ultrasonic rheometers are using delay lines in glass or quartz and normal or oblique incidence of ultrasonic rays. The oblique incidence is used in order to improve the sensitivity of the measurements. We theoretically demonstrate in this work that the use of delay lines in polymers is recommended to improve the sensitivity. Due to modifications, performed on a 10 MHz commercial ultrasonic sensor, we experimentally show on glycerin (which is a Newtonian material) that it is possible to multiply by a factor 10 the sensitivity; compared to delay lines in quartz using a normal incidence of rays. Hence, we overpass the accuracy of the oblique incidence approach with a simpler experimental setup. 相似文献
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将一等效薄片模型嵌入到时域有限差分算法(FDTD)中,以快速而有效地解决复合材料薄片在电磁计算中的多尺度问题。在该嵌入式薄片模型中,薄片不需要被剖分网格,而是被嵌入到相邻的网格间,从而可以使用相对较大的网格剖分周围物体,进而可节省大量的计算资源。在这一模型中,薄片被等效为一段传输线,并用其频域的导纳矩阵代替。使用数字滤波器理论以及逆Z变换可将频域的导纳矩阵转换到时域,并将其嵌入到时域有限差分算法中。该嵌入式薄片模型被用来计算一单层碳纤维复合材料薄片的反射以及透射性能,并与其解析解进行对比,从而验证该模型的准确性、收敛性以及高效性。该模型被用来计算三种具有不同电参数的单层碳纤维复合材料薄片的屏蔽性能,以研究各电参数对其屏蔽性能的影响。 相似文献
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以有限元法为理论分析手段模拟分析了温度梯度法合成宝石级金刚石大单晶的腔体温度场,实现了对宝石级金刚石的合成腔体内各位置温度同时测量.模拟结果表明:在宝石级金刚石合成过程中,其温度分布呈不均匀分布.腔体内高温区分布在样品(碳源+触媒)边缘,低温区分布在籽晶附近.样品腔内热量的传递方式和样品腔内的碳源输运方式相同,均由碳源的两侧向籽晶附近传输.籽晶附近轴向温度梯度大于径向温度梯度,导致单位时间内其轴向生长尺寸大于径向生长尺寸.宝石级金刚石腔体温度场分析的理论模型的成功构建,为新型宝石级金刚石腔体的研制提供了良好的设计基础,对促进优质宝石级金刚石的生长技术具有指导意义. 相似文献
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This paper studies the damage-viscoelastic behavior of composite solid propellants of solid rocket motors(SRM).Based on viscoelastic theories and strain equivalent hypothesis in damage mechanics,a three-dimensional(3-D)nonlinear viscoelastic constitutive model incorporating with damage is developed.The resulting viscoelastic constitutive equations are numerically discretized by integration algorithm,and a stress-updating method is presented by solving nonlinear equations according to the Newton-Raphson method.A material subroutine of stress-updating is made up and embedded into commercial code of Abaqus.The material subroutine is validated through typical examples.Our results indicate that the finite element results are in good agreement with the analytical ones and have high accuracy,and the suggested method and designed subroutine are efficient and can be further applied to damage-coupling structural analysis of practical SRM grain. 相似文献
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Recent experimental and numerical studies have shown that the interaction between a localized vortical disturbance and the shear of an external base flow can lead to the formation of counter-rotating vortex pairs and hairpin vortices that are frequently observed in wall bounded and free turbulent shear flows as well as in subcritical shear flows. In this paper an analytical-based solution method is developed. The method is capable of following (numerically) the evolution of finite-amplitude localized vortical disturbances embedded in shear flows. Due to their localization in space, the surrounding base flow is assumed to have homogeneous shear to leading order. The method can solve in a novel way the interaction between a general family of unbounded planar homogeneous shear flows and any localized disturbance. The solution is carried out using Lagrangian variables in Fourier space which is convenient and enables fast computations. The potential of the method is demonstrated by following the evolved structures of large amplitude disturbances in three canonical base flows, including simple shear, plane stagnation (extensional) and pure rotation flows, and a general case. The results obtained by the current method for plane stagnation and simple shear flows are compared with the published results. The proposed method could be extended to other flows (e.g. geophysical and rotating flows) and to include periodic disturbances as well. 相似文献
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针对滑移区复杂气-固边界存在速度滑移现象,提出了一种基于格子Boltzmann方法的非平衡态外推与有限差分相结合的曲边界处理新格式.该格式具有可考虑实际物理边界与网格线偏移量的优势,较传统half-way DBB(diffusive bounce-back)格式更能准确反映实际边界情况,同时还可获取壁面处气体宏观量及其法向梯度等信息.采用本文所提曲边界处理格式模拟分析了滑移区气体平直/倾斜微通道Poiseuille流、微圆柱绕流和同心微圆柱面旋转Couette流问题.研究结果表明,采用曲边界处理新格式所得结果与理论值以及文献结果符合良好,适用于滑移区气体流动的复杂边界处理,且比half-way DBB格式具有更高的精度,较修正DBB格式具有更好的适应性. 相似文献
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