Analysis on a Set of 12-parameter Rectangular Plate Element with High Accuracy

It is proved that the so-called a set of 12-parameter rectangular plate elements with high accuracy constructed by using double set parameter method and undetermined method are, in fact, the same one; the real shape function space is nothing but the Adini＇s element＇s, which has nothing to do with the other high degree terms and leads to a new method for constructing the high accuracy plate elements. This fact has never been seen for other conventional and unconventional, conforming and nonconforming rectangular plate elements, such as Quasi-conforming elements, generalized conforming elements and other double set parameter finite elements. Moreover, such kind of rectangular elements can not be constructed by the conventional finite element methods.

Parameter identifications for a rotor system based on its finite element model and with varying speeds

In order to achieve prediction for vibration of rotating machinery, an accurate finite element （FE） model and an efficient parameter identification method of the rotor system are required. In this research, a test rig is used as a prototype of a rotor system to validate a novel parameter identification technique based on an FE model. Rotor shaft vibration at varying operating speeds is measured and correlated with the FE results. Firstly, the theories of the FE modelling and identification technique are introduced. Then disk unbalance parameter, stiffness and damping coefficients of the bearing supports on the test rig are identified. The calculated responses of the FE model with identified parameters are studied in comparison with the experimental results.

Calibration of Discrete Element Heat Transfer Parameters by Central Composite Design

The efficiency and precision of parameter calibration in discrete element method （DEM） are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibration for granular heat transfer with the DEM is studied. The heat transfer in granular assemblies is simulated with DEM, and the effective thermal conductivity （ETC） of these granular assemblies is measured with the transient method in simulations. The measurement testbed is designed to test the ETC of the granular assemblies under normal pressure and a vacuum based on the steady method. Central composite design （CCD） is used to simulate the impact of the DEM parameters on the ETC of granular assemblies, and the heat transfer parameters are calibrated and compared with experimental data. The results show that, within the scope of the considered parameters, the ETC of the granular assemblies increases with an increasing particle thermal conductivity and decreases with an increasing particle shear modulus and particle diameter. The particle thermal conductivity has the greatest impact on the ETC of granular assemblies followed by the particle shear modulus and then the particle diameter. The calibration results show good agreement with the experimental results. The error is less than 4%, which is within a reasonable range for the scope of the CCD parameters. The proposed research provides high efficiency and high accuracy parameter calibration for granular heat transfer in DEM.

基于APDL的船用电梯井架参数化建模与仿真

基于APDL软件,对船用电梯井架进行参数化建模和有限元分析,实现了电梯井架的快速设计、优化和分析。具体方法是采用多面体拼接法对电梯井架进行几何建模,然后定义参数化变量,通过改变参数化变量的值来实现电梯井架的参数化设计。最后利用有限元分析方法对电梯井架进行仿真分析。结果表明,该方法能够提高设计效率,减少制造成本,同时也能保证产品质量。因此,在电梯井架的设计和制造中具有一定的应用价值。通过调整参数、进行工程设计的优化,可以在设计阶段找到成本效益最佳的设计方案,从而避免了在后期制造和维护过程中出现意外的高成本,帮助预测维护成本和整个产品的生命周期成本。

电路参数对石墨加热元件发热特性的影响规律研究

电路参数是石墨加热元件发热性能的决定性因素,对电路参数的影响规律研究是高性能、高可靠性石墨加热器设计的基础。对石墨加热装置的失效过程进行研究,确定发热元件可靠性量化指标——温度均匀度;在此基础上,确定对加热元件热输出性能进行量化的四个电路参数:加热元件厚度、发热条宽度、发热条缝隙、缝隙处的倒圆半径;对发热电路进行参数化建模,并采用有限元电热耦合仿真对加热元件电路参数对加热能力和可靠性的影响机理进行研究。结果表明:加热元件的厚度决定了其热输出能力,而其余三个电路参数决定了加热元件的可靠性。本文的研究成果对高性能石墨加热装置的研制具有重要的支撑作用。

基于参数化建模方法的复合式盾构机刀盘力学性能分析与结构优化

刀盘是盾构机的核心部件之一,合理的刀盘结构设计是安全高效掘进的基础。为了快速高效建立刀盘有限元模型并分析其力学性能,采用基于APDL(ANSYS parametric design language)命令流开发的参数化建模方法,建立某型号复合式盾构机刀盘的数字模型。对刀盘施加极限工况下的推力和扭矩,通过静力学分析得到刀盘的应力分布和变形分布,确定最大应力和最大变形位置,校核刀盘的静强度和静刚度。进一步以刀盘总质量为优化目标,以刀盘强度和刚度为约束条件建立基于参数化建模的刀盘结构优化方法,提出刀盘结构优化流程。通过参数敏感性分析确定刀盘优化参数,探究相关参数对刀盘强度和刚度的影响。对复合式盾构机刀盘的关键参数进行优化。结果表明:优化后刀盘的最大应力降低了12%,最大变形降低了20%,质量减轻了119 kg。因此,基于参数化建模的优化方法可以提供刀盘的强度与刚度,并同时降低刀盘质量。研究成果可为后续多目标刀盘结构优化提供参考。

直升机ACF智能旋翼压电叠堆输出特性仿真分析

压电叠堆是ACF智能旋翼中后缘襟翼的致动元件,其输出性能的好坏直接影响后缘襟翼的偏转效率。基于COMSOL Multiphysics有限元平台,对全电极和叉指电极两种构型的压电叠堆进行了参数化建模,对叠堆自由位移和阻塞力两种典型输出特性进行了仿真分析,并利用理论进行了校验。结果表明,基于参数化建模的压电叠堆有限元模型具有良好的准确性,其计算结果与理论模型计算结果基本保持一致;两种构型压电叠堆的输出特性随激励电压的变化都是趋于线性的;相同激励电压下,同横截面积的叉指电极型压电叠堆的自由位移小于全电极型,减小比例与各陶瓷层活性区面积的缩减比例一致,而两种构型叠堆的阻塞力大小相当,叉指电极的尺寸缩进不会使得阻塞力明显降低。

基于Creo的角变位斜齿轮副建模及轮齿强度分析

针对角变位斜齿轮强度计算和校核验算复杂的问题,文中利用有限元分析技术,验证了一组用于某型号钢丝绳起重葫芦起升减速器末级的外啮合角变位圆柱斜齿轮副设计合理性的方法,其包括利用Creo软件平台的Creo Parametric模块进行外啮合角变位圆柱斜齿轮渐开线齿廓的精确参数化三维建模,采用Creo Simulate模块进行静力学模拟仿真分析。模拟分析结果可输出轮齿各部位的详细应力情况,作为齿轮设计、强度计算校核的重要参考。熟练运用本方法,可减少大量繁杂的手工计算和翻阅手册查找公式、参数、系数的时间。

矿用减速器直齿轮强度动态有限元分析

传统的齿轮接触应力和弯曲应力是利用理论计算进行静强度校核。为了提高齿轮传动中接触应力和弯曲应力的计算精度与效率,利用Creo2.0软件快速建立了某矿用减速器直齿圆柱齿轮的参数化模型,并使用ABAQUS软件及其子模型技术对齿轮最大接触应力和齿根最大弯曲应力进行动态分析,从而为齿轮的设计及优化提供一种新的设计方法。

基于BIM技术的异形空间结构参数化设计

设计人员传统的设计思路为根据设计经验对建筑造型和结构进行设计,而场馆建筑造型独特且复杂,设计难度大,传统的设计方法繁琐且需消耗大量的设计资源,不能很好地解决异形场馆建筑结构中的复杂问题。本文以某异形空间结构为研究对象,采用参数化技术对该异形空间结构进行设计,将BIM设计理念融入设计中,解决结构选型分析问题,运用Grasshopper建立该结构的参数化模型,并运用Abaqus对所建立的参数化模型进行计算分析和结构力学特性的优化,最后利用BIM软件进行三维模型应用,为结构工程师解决异形空间结构的设计提供新的思路和方法。

基于参数化思想的井下滚轴筛设计

为适应煤矿井下筛分对设备安装检修、硐室设计以及减少筛分土建投资等方面的要求,针对现有装备的不足,运用参数化设计思想,通过筛分过程的仿真以及关键部件的有限元分析,进行了井下滚轴筛的设计。最终确定:井下滚轴筛采用三段分体模块化结构,以便于设备的安装和维护,三段筛面连接后呈香蕉形,各段箱体均采用全密封结构,无粉尘外溢且噪声低;筛面宽度应大于物料的最大粒度(D_(max))的3倍,筛面长度应为筛宽的3~8倍;每根筛轴均通过弹性柱销联轴器与筛箱外侧的驱动电机一一相连,可对每根筛轴的转速进行实时调整,同时也方便检修和维护;筛盘所受应力为0.018 MPa,位置在齿尖处,筛轴以弯曲应力为主,最大应力为1.71 MPa,位置在轴承处,二者材质均选用经调质处理的45_#钢,可满足使用要求;优化筛轴转速、筛面倾角等因素可优化筛分效率;采用迭代算法进行优化,可在筛分效率最大化的前提下最大限度地提高滚轴筛处理量。运用参数化思想设计得到的井下滚轴筛达到了设计目标,为井下筛分的推广应用提供了一定的装备基础。

Influence of process parameters on deep drawing of AA6111 aluminum alloy at elevated temperatures

To gain a deep insight into the hot drawing process of aluminum alloy sheet, simulations of cylindrical cup drawing at elevated temperatures were carried out with experimental validation. The influence of four important process parameters, namely,punch velocity, blank holder force(BHF), friction coefficient and initial forming temperature of blank on drawing characteristics(i.e.minimum thickness and thickness deviation) was investigated with the help of design of experiments(DOE), analysis of variance(ANOVA) and analysis of mean(ANOM). Based on the results of ANOVA, it is shown that the blank holder force has the greatest influence on minimum thickness. The importance of punch velocity for thickness deviation is 44.35% followed by BHF of 24.88%,friction coefficient of 15.77% and initial forming temperature of blank of 14.995%. After determining the significance of each factor on forming characteristics, how the individual parameter affects characteristics was further analyzed by ANOM.

Optimal design of structural parameters for shield cutterhead based on fuzzy mathematics and multi-objective genetic algorithm

In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters for shield cutterhead is formulated,based on the complex engineering technical requirements. In the model, as the objective function of the model is a composite function of the strength and stiffness, the response surface method is applied to formulate the approximate function of objective function in order to reduce the solution scale of optimal problem. A multi-objective genetic algorithm is used to solve the cutterhead structure design problem and the change rule of the stress-strain with various structural parameters as well as their optimal values were researched under specific geological conditions. The results show that compared with original cutterhead structure scheme, the obtained optimal scheme of the cutterhead structure can greatly improve the strength and stiffness of the cutterhead, which can be seen from the reduction of its maximum equivalent stress by 21.2%, that of its maximum deformation by 0.75%, and that of its mass by 1.04%.

Effect of Dimension Parameters on the Torsion Property of A C/SiC Pipe

Through finite element numerical simulation and based on laminated plate theory, the effect of dimension on the torsion properties of uniform C/SiC composites pipe was studied to provide a theoretical guidance for preparing the C/SiC pipe with different dimensions. The results show that, with increasing length of pipe, the anti-torsion section coefficient of pipe increases whereas the torsion angle per unit length decreases. Increasing the length can improve the torsion property. Anti-torsion section coefficient rises with increasing internal radius, while the torsion angle per unit length decreases to a constant. With increasing thickness, the anti-torsion section coefficient increases whereas the amplitude decreases gradually, and the torsion angle per unit length is a constant. Increment of internal radius and thickness improves the torsion property finitely.

基于增材制造的点阵结构优化

现有商业软件在构造拥有曲面边界轮廓的点阵结构时,会出现单胞破损现象,边界单胞破损的点阵结构不仅外观上有缺陷,而且力学性能较差,因此开发出一套大规模点阵结构的构造与优化设计方法非常具有理论价值和实际工程意义。首先,针对目前大规模点阵结构构造时存在的边界单胞破损问题,在有限元网格划分技术的基础上,提出了一种完整单胞的点阵结构构造方法;然后,将ANSYS的参数化语言APDL应用到具体的二维和三维实例中,并将该文提供的点阵结构与主流拓扑软件Inspire构造的点阵结构进行对比,结果表明基于有限元网格划分技术构造的点阵结构适应于不同的直线、曲线和曲面图形,较好地避免了几何图元边界处的单胞破损现象;最后,针对构造的含有完整单胞的均质点阵结构进行非均质优化,在MIST方法的基础上,提出了一种点阵结构杆件直径尺寸快速优化设计方法,分别应用到二维和三维仿真数值算例中,并选取合适的模型进行3D打印,通过点阵结构的压缩试验,进一步验证了非均质点阵结构优化设计方法的有效性。

采用Solidworks的对数螺旋锥齿轮结构设计与力学分析

对数螺旋锥齿轮是机械传动机构中的重要零部件,运用SolidWorks软件结合C语言编程,建立了参数化齿轮数值表,并基于尺寸驱动参数化方法,创建了一对对数螺旋锥齿轮的三维模型。通过对齿轮进行啮合装配和运动分析,验证了所设置的齿轮参数的结构合理性。此外,利用Solidworks模块Simulation进行网格划分,进行了实体网格的非线性有限元分析。研究重点在于探究不同转矩载荷下螺旋锥齿轮啮合部位的最大接触应力、接触强度和接触应变等方面。这些研究结果能够确保设计的螺旋锥齿轮具备足够的强度和可靠性。经校核,对数螺旋锥齿轮的接触强度在最佳转矩范围内低于60.5 N·m,其啮合最大应力值小于材料的屈服极限,结果为对数螺旋锥齿轮的结构设计和传动强度提供了可靠的参考和方法,这对于相关领域的工程实践和齿轮设计具有重要的指导意义。

基于APDL的叶脉参数化建模与有限元分析

为了探索植物叶脉对滚动接触摩擦副表面摩擦磨损性能的影响,这里基于APDL参数化设计语言,以叶脉为研究对象,对ANSYS软件进行了二次开发,实现了叶脉的有限元参数化建模。同时,利用ANSYS/LS-DYNA求解器、LS-PREPOST后处理器对“滚子-叶脉”系统进行了显式动力学分析。结果表明:应用APDL编程和ANSYS的二次开发,可以实现叶脉有限元参数化建模和动力学分析的全过程。这为进一步研究叶脉对滚动接触摩擦副的影响机理提供了思路,也为叶脉拓扑结构的优化奠定了基础。

基于代理模型的地铁隧道结构变形预测数字孪生方法

目的:以地铁隧道邻近基坑开挖为典型场景,提出一种基于代理模型的地铁隧道结构变形预测数字孪生方法。方法:构建了邻近基坑开挖引发地铁隧道变形的参数化有限元模型,筛选13个关键参数作为模型输入,以隧道上5个不同位置的横向位移与竖向位移作为模型输出;通过均匀设计生成有限元算例样本,基于BP(反向传播)神经网络建立代理模型,以工程实测数据进行模型验证。结果及结论:隧道横向位移和竖向位移在训练集和验证集上的预测精度大于91.38%,在测试集上的预测精度大于80.00%,计算时间为毫秒级;以上海浦东地区某地块基坑工程案例进行验证,代理模型预测值与工程实测值的误差小于1.5 mm,表明代理模型能够准确预测邻近基坑开挖引发的地铁隧道变形;该方法准确率和实时性初步达到了隧道运维数字孪生应用的性能要求。

基于多目标遗传算法的差速器壳体轻量化设计

针对某新能源汽车差速器壳体需在满足行驶工况的刚强度要求下实现轻量化,提出一种基于多目标遗传算法NGSA-Ⅱ和参数化模型相关联的优化设计方法。首先通过SolidWorks和ANSYS的联合仿真,对差速器壳体的大端、小端、法兰及主减速器外圆等部位的厚度实现参数化手段,并通过模态分析和静力学计算证明壳体有足够的优化空间;然后构建尺寸变量同优化目标之间的响应曲面;最后基于多目标遗传算法,建立以质量最小和壳体最大应力最小为目标的优化模型,对差速器壳体进行轻量化设计。结果显示:优化后壳体总质量从6.80 kg减为6.10 kg,减少了10.3%;壳体最大应力降低了9.9%;同时壳体的最大变形量在安全范围内,证明基于多目标遗传算法进行轻量化设计是可行的。

门座起重机门架的参数化有限元分析及实验验证

门座起重机的门架结构承载旋转部分的所有载荷,在使用过程中时常因交变应力作用而出现金属结构焊缝开裂的情况。为了从设计角度、维修保养方面有效避免此类问题出现,对具有复杂结构的门架开展有限元分析十分有必要。文中利用Ansys的参数化设计语言进行参数化建模、分析,并用VB软件封装,建立了一套可视化的门座起重机门架有限元分析软件。此外,利用统计学方法对实际在用门座起重机的门架开展理论仿真值和实测值之间的验证。结果表明有限元分析值与实际测试值基本相符,所建立的参数化软件分析数据可靠。