滚塑成型技术的研究现状及其展望

随着世界塑料产品市场的快速发展以及塑料技术的日益成熟,与注塑、吹塑成型等成型方法相比,滚塑在大型及超大型中空类容器(储罐、槽等)成型方面具有不可替代的作用,应用领域不断拓宽.在介绍了滚塑成型原理的基础上,根据滚塑成型用料要求归总了各种滚塑适用原料并进行了对比,综合分析了滚塑成型设备的研究现状以及滚塑技术的发展前景.     

半固态成型技术的发展与应用现状

为了解决半固态成型技术中引起人们广泛关注的主要问题,加深人们对半固态成形技术的认识,以半固态成型技术区别于液态成型和塑性成型的本质为基础,采用对比讨论的方法分析了半固态成型技术的特点与优势,阐明了半固态成型技术的种类和区别,介绍了半固态成型技术的国内外应用现状。指出了推动我国半固态成型技术长足发展和应用应该注意解决的若干瓶颈。     

喷射粘接快速成型技术的原理、成型特性及关键部件

本文主要论述了喷射粘接快速成型的基本原理,成型工艺特性（包括成型速度的影响因素及提高成型速度的途径、成型物体尺寸误差的主要来源与控制、成型物体的表面质量的影响因素及提高表面质量的方法）,最后论述喷射粘接成型系统的关键部件—喷嘴,根据粘接剂微粒的特性,提出了一种实际可行的喷嘴结构。     

辊弯成型力能参数研究

通过对辊弯成型变形能量解析,按照外力做功和内力做功相等的原理,建立了辊弯成型力矩和成型力的理论计算公式.分析了板厚、弯曲半径和弯曲角三个因素对成型力矩和成型力的影响趋势.随着板厚h值的增大成型力矩M成指数形式增大,成型力F的值随着显著增大,而在弯曲半径R增大时成型力M以指数形式下降和成型力F显著减小,弯曲角增大时成型力增大和成型力矩线性增大.     

板料成型性能指数对钣金零件成型工艺性的影响

这里详细论述了板料成型性能指数n、r值的物理意义及其对各种钣金零件成型工艺性的影响，结合典型成型工艺，利用钣金冷压成型原理，对n、r值的具体影响进行了分析研究，得出了一些针对具体成型工艺的一般规律性的结论。将这里的一些概念和分析研究的结果同具体的生产实践相结合，则会对促进生产和提高成型件的质量有一定的指导意义。     

喷射粘接快速成型技术的原理,成型特性关键部件

本文主要论述了喷射粘接快速成型的基本原理，成型工艺特性（包括成型速度的影响因素及民型速度的途径、成型物体尺寸误差的主要来尖与控制、成型物体的表面质量的影响因素及提高表面质量的方法），最后论述喷射粘接成型系统的关键部件－－喷嘴，根据粘接剂向来闰的特性，提出了一种实际可行的喷嘴结构。     

金属直接成型技术的发展与展望

对当今快速成型技术的研究热点———各种金属直接成型技术进行了介绍和分析 ,提出了堆焊与数控铣削相结合的成型工艺方案     

控制FDM成型制件误差的方法研究

快速制模是快速成型的主要应用之一,但成型件的精度难以达到快速制模对原型或型芯尺寸精度和表面精度的要求.系统分析了熔融堆积成型( FDM)工艺成型精度的影响因素,分析产生误差的根源及作用机理.针对FDM产生的误差,通过定性和定量分析,提出减小误差的途径和方法,并通过实例验证了解决翘曲变形和尺寸精度问题的方法,提高了原型的精度,对熔融堆积成型工艺精度的提高具有实际的参考价值.     

快速成型技术发展方向探讨

通过分析八种快速成型的新方法和新工艺，探讨了快速成型的发展方向。认为快速成型将向复合成型、降低成本、简化工艺，提高速度和精度的方向发展。     

基于焊接的金属成型技术的发展

快速成型技术发展至今，金属材料直接成形已成为其研究热点和一个重要发展方向。这里介绍了金属直接成型技术的工艺方法，并详细阐述了焊接快速成型工艺的发展情况及其关键技术。焊接成型技术是一种非常实用且制造成本低的快速制造方法，成型零件具有优良的强度和性能。随者焊接成型的深入研究和关键问题的解决，其必将在制造领域发挥巨大作用。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...