A state space solution for the bending problem of thick laminated piezoelectric open cylindrical shells

Based on the theories of three-dimensional elasticity and piezoelectricity, and by assuming appropriate boundary functions, we established a state equation of piezoelectric cylindrical shells. By using the transfer matrix method, we presented an analytical solution that satisfies all the arbitrary boundary conditions at boundary edges, as well as on upper and bottom surfaces. Our solution takes into account all the independent elastic and piezoelectric constants for a piezoelectric orthotropy, and satisfies continuity conditions between plies of the laminates. The principle of the present method and corresponding results can be widely used in many engineering fields and be applied to assess the effectiveness of various approximate and numerical models.     

Optimal constrained multi-degree reduction of Bézier curves with explicit expressions based on divide and conquer

We decompose the problem of the optimal multi-degree reduction of Bezier curves with comers constraint into two simpler subproblems, namely making high order interpolations at the two endpoints without degree reduction, and doing optimal degree reduction without making high order interpolations at the two endpoints. Further, we convert the second subproblem into multi-degree reduction of Jacobi polynomials. Then, we can easily derive the optimal solution using orthonormality of Jacobi polynomials and the least square method of unequally accurate measurement. This method of ＇divide and conquer＇ has several advantages including maintaining high continuity at the two endpoints of the curve, doing multi-degree reduction only once, using explicit approximation expressions, estimating error in advance, low time cost, and high precision. More importantly, it is not only deduced simply and directly, but also can be easily extended to the degree reduction of surfaces. Finally, we present two examples to demonstrate the effectiveness of our algorithm.     

综合平衡法在浸渍-升华工序工艺参数分析中的应用

为了提高干冰膨胀烟丝质量,针对浸渍-升华工序对膨胀后烟丝质量的影响,文章采用正交试验设计与综合平衡法对升华温度、蒸汽流量、塔内风速、浸渍时间4个工艺参数进行了分析,结果表明:在试验范围内,升华温度320℃,蒸汽流量800-1000 kg/h、塔内风速34 m/s,浸渍时间30秒,为最佳工艺参数,按此参数生产的膨胀烟丝综合质量最优。     

基于正交实验法的低速走丝线切割气中精加工工艺参数的研究

为了进一步提高低速走丝线切割的表面质量,本文采用了气液混合多次切割的工艺。并采用正交设计法研究了脉冲宽度、脉冲间隔、峰值电流、伺服电压、伺服进给速度5个因素对表面粗糙度的影响,并通极差分析和利用二元表找出了在考虑上述5个因素交互作用下各因素的最佳水平,为进一步研究低速电火花线切割加工工艺提供了基础。     

银黄颗粒提取工艺研究

目的:寻找出一种银黄颗粒提取率最优的工艺。方法:以黄芩苷与绿原酸为主要指标,用正交试验法进行考察。结果:能将金银花以最优的方法提取出来的工艺为:用12倍水,将石灰乳浓度控制为百分之二十,硫酸的浓度控制在百分之十。能将黄芩以最优的方法提取出来的工艺为:8倍水,将硫酸浓度控制在百分之十,温度控制在70摄氏度。结论:本文所用工艺稳定易行,比传统的工艺更具有优势。     

正交试验法在燃煤工业锅炉燃烧调整中的应用

本论文以沈阳市某厂的20吨/小时蒸汽锅炉燃烧调整的能效测试为基础,采用正交试验的方法,科学合理设置试验因素和水平,找出排烟温度、过量空气系数、排烟处CO百分含量、炉渣含碳量对锅炉效率的影响关系。通过试验得到燃煤工业锅炉在不同水平下各主要运行参数与效率的关系曲线,并找到其最佳运行状态点,提高锅炉运行的经济性和安全性。     

正交试验法优化香樟根总黄酮提取工艺

[目的]采用乙醇提取法,优选香樟根总黄酮的提取工艺。[方法]选择乙醇浓度、料液比、提取温度、提取时间为考察因素,采用正交设计L9（34）进行提取工艺优选试验。[结果]回归方程为：Y=13.68X-0.0027,r2=0.998,芦丁浓度在0.0—0.04516mg/mL范围内有良好线性关系,最佳提取工艺为：乙醇的体积分数为50%,料液比为1：20,温度为70℃,提取时间为2h。[结论]优选的提取工艺简单、易行,可作为开发香樟根制剂的依据。     

巧用“分解加速度”解题

对力进行正交分解是常用方法,而在有些问题中对加速度进行正交分解,能够使解题更简洁．     

基于ANSYS的素土坯墙体抗震性能影响因素分析

针对素土土坯墙体的抗侧承载力和变形能力影响因素,采用数理统计理论中的正交试验因素分析方法,对素土坯墙体的静力弹塑性有限元非线性数值模拟计算结果进行了对比分析.研究了素土坯墙体厚度、洞口尺寸和竖向载荷对墙体抗侧承载力和变形能力影响程度.结果表明:未开孔的素土坯墙体,墙体厚度和竖向压应力对墙体的极限位移和极限载荷的提高具有同等重要的程度;开孔的素土坯墙体,墙体厚度、竖向压应力和开孔大小,对墙体的变形能力和抗侧承载力的提高程度相比较,竖向压应力的影响较大.     

预处理的BiCGSTAB算法及其在涡流求解中的应用(英文)

针对涡流场有限元分析形成的大型稀疏复线性方程组,提出了预处理稳定双共轭梯度法(PBiCGSTAB).利用二维正交链表结构实现系数矩阵的全稀疏存储,采用无填充的不完全LU分解对方程组进行预处理以降低系数矩阵的条件数.将稳定双共轭梯度法从实数领域扩展到复数领域,并利用它求解预优过的复线性方程组.基于有限元法和PBiCGSTAB算法编制直线电机性能分析软件,并对一电机堵转的情况进行仿真,将计算结果和ANSYS计算出的结果进行了比较,证明了该软件的正确性.并且通过求解器比较发现,在相同精度条件下PBiCGSTAB算法只需要BiCG算法三分之一的迭代步数,证明了该算法的快速性.