基于MBD的全三维参数化建模技术

分析了基于模型定义的技术概念与数据集的内容,以及它在规范树上的表达方式.在零件建模中引入MBD技术,通过MBD的技术要求建立规范的MBD模型,并且在新的MBD模型中引入了参数化的概念,提出了基于模型定义的全三维参数化建模方法.以某飞机框类零件为例,建立了基于MBD的某飞机框类零件参数化模型.应用此建模方法能够大幅度提高设计效率,减少设计工作量,进而缩短产品的开发周期.     

船用柴油发电机组非线性隔振系统动态特性分析

以计算多体动力学理论为指导,以船舶柴油发电机组的抗冲击研究为背景,建立了柴油发电机组的多体动力学以及线性隔振系统模型,并通过实验验证模型的正确性;在此基础上构建机组的非线性隔振系统,并对机组额定工况以及冲击条件下隔振系统的动态特性进行分析,结果表明非线性隔振系统较线性隔振系统有良好的隔振效果。文中的建模与求解方法较数学建模与求解简单易行,对隔振器选型与安装、非线性隔振器的参数化设计与优化、其它船用机械的抗冲击研究奠定了一定的工程应用基础。     

虚拟式风电机组功率特性测试仪的研发

为了实现对风电机组功率特性的测试,依据IEC标准对风电机组的功率特性测试的方法、原理进行了研究,提出了风电机组功率特性的现场测试方法,并且结合现代虚拟仪器技术设计并开发出实用的风电机组功率特性测试分析仪,该仪器是在VMIDS系统基础上成功研制出来的,在成功完成对风电机组各参数提取的同时,能分析出风电机组的各项特性.     

空调机组三维参数化设计及装配仿真

以Pro／Engineer软件为平台,探讨并开发了组合式空调机组三维参数化设计及装配仿真系统。提出了空调机组零部件采用设计变量、用户定义特征库（UDF）、表格驱动与编程相结合的三维参数化设计方法,实现了零部件三维参数化特征建模。建立了合理的装配规划,实现了段体的自动装配、约束识别及装配干涉分析。为实现空调机组产品的三维设计提供了先进的设计手段。     

基于构件几何要素的型材参数化设计与库建立

在CATIA平台上,利用其二次开发接口CAA对零件的参数化设计方法进行研究与阐述,提出了基于构件主要几何要素开展参数化设计的思路.以某型材类零件为例,在构件要素的基础上建立零件的参数化模型,并进一步建立该类型材的模型库.这种方法不仅可以大大提高建模效率,也可弥补同类型材标准件应用时不能因地制宜的缺点.     

基于功率曲线分析与神经网络的风电机组故障预警方法

为尽早发现风电机组早期故障,减少风电场的运维成本,提出一种基于功率曲线分析与神经网络的故障预警方法。首先,依据功率特性曲线,使用最小二乘与离散度分析结合的算法对SCADA数据进行筛选,以保留符合机组正常工况的数据作为建模的训练数据,从而提高模型的精度。然后,使用随机森林算法筛选模型的输入参数以简化模型结构,并通过对比隐含层的数目建立风电机组的神经网络模型。最后,结合滑动窗口模型,提出一种能反映机组实时运行状态的指标,并通过非参数估计法确定该指标的阈值,以实现状态预警及在线监测。该方法充分利用SCADA数据,且不需要对风电机组复杂的物理特性进行分析。将该方法分别用于某风电场的变桨系统和偏航系统的故障预警,实验结果是分别提前18.5 h和28.4 h出现预警信号,进一步证明方法的有效性。     

对风力发电新技术及并网稳定问题与探讨

风力发电是我们重要的安全可再生新能源。对风电机组及其建模技术、风电接人电网技术以及一些新技术的应用进行了综述分析,对有关风电并网后对电网稳定影响的研究进行了总结和探讨,对风力发电技术奠定了坚实的基础。     

基于参数化技术的隧道三维建模方法

针对已有隧道三维建模方法缺少交互性和多样性的不足,提出了基于参数化建模技术的隧道三维建模与景观仿真方法。试验表明,该方法能够快速和有效的建立多种景观隧道三维模型,能将隧道三维设计与三维场景形象直观的表现出来,满足隧道三维建模快速、多样性和交互性的要求。     

滚动轴承参数化设计关键技术研究

Pro/ENGINEER是应用广泛的CAD/CAM/CAE集成软件系统,在Pro/ENGINEER系统中,骨架模型可以完成产品的自顶向下设计,Program可以完成产品的参数化自动生成.通过将骨架模型技术和Program相结合,研究滚动轴承参数化建模的产品结构定义和模型控制过程,进而结合设计实例给出滚动轴承参数化设计的详细步骤.结果表明这种设计方法能够实现滚动轴承的多样化和系列化设计,大大缩短滚动轴承的产品开发周期.     

基于足部CT图像的个体鞋楦的参数化设计

提出并实施了以人体足部复合模型为依据的鞋楦参数化建模方法.基于足部CT图像建立了由足部骨骼模型和软组织模型组成的复合模型.研究和建立了鞋楦特征点以及特征点之间的参数关系.在通用CAD软件环境下,建立了面向个体的鞋楦参数化模型,实现了两个主参数对整个鞋楦体的控制.最后给出了参数化建模的两个结果的比较.     

单桩基础型近海风机系统自振频率实用计算方法

"软-刚"（soft-stiff）设计的系统频率限制是海上风电结构与基础设计的关键性难点之一。该文基于有阻尼系统运动方程,考虑桩土相互作用和风机塔筒的变截面特性,建立了单桩基础型近海风机系统自振频率求解数值计算方法。利用实际工程进行了方法应用和有效性验证。频率偏移因素分析表明,地基土模量非均一对系统自振频率影响较小;系统自振频率对地基弹性模量、海床高度变化、桩径的敏感性较强,对地基土阻尼的敏感性较弱。同时,该文方法可以精确分析海上风机在服役期间的系统自振频率的偏移,为近海风机的结构和基础设计提出有效评估,并建议减小频率偏移的工程措施。     

Multi-objective material selection for wind turbine blade and tower: Ashby’s approach

The world today is continuously striving towards carbon neutral clean energy technology. Hence, renewable energy sources like wind power system is increasingly receiving the attention of mankind. Energy production is now no more the sole criterion to be considered when installing new megawatt (MW) range of turbines. Rather some important design parameters like structural rigidity, cost effectiveness, life cycle impact, and, above all, reduced mass come into the scenario from new installation point of view. Accordingly, these issues are followed up in this article from wind turbine design perspective. The study, at the outset, aims to establish blade and tower material selection indices on the basis of inherent structural constraints and potential design objectives. Next, it highlights entire blade and tower material selection aspects for small and large scale horizontal axis wind turbines, both for onshore and offshore application. Finally, it distinguishes advanced blade and tower materials in agreement with multiple constraint, compound objective based design optimization procedure. Findings from the study can be deployed to harness massive scale wind energy from structurally more promising, economically more competitive and environmentally more clean and green turbines.     

基于面元法的风力机翼型反设计

在风力机初步设计阶段,获得准确的气动特性数据可以大幅度缩减生产和测试的周期,因此开发速度快、精度高的设计方法具有重要的工程实用价值。该文运用余弦分隔法表征翼型,建立了常值偶极子面元法翼型绕流气动分析模型。通过与实验数据和Xfoil计算值的对比,总结出在攻角[-8o,8o]范围内,上述模型是可行的。然后,利用改进的Hicks-Henne型函数对翼型的几何外形进行参数化建模,并采用二次序列规划法作为寻优算法,建立了以最小压强系数标准差为目标函数的反设计模型。根据40个~280个面元的运算结果,得出当面元数取60个~ 100个时,模拟分析效率高。最后,选择具有不同厚度分布或对称性的基准翼型分别模拟分析,计算表明收敛精度都非常高。从而验证了该反设计方法的合理性、有效性及强鲁棒性。     

Short-Term Wind Speed Forecast Using Measurements From Multiple Turbines in A Wind Farm

Turbine operations in a wind farm benefit from an understanding of the near-ground behavior of wind speeds. This article describes a probabilistic spatial-temporal model for analyzing local wind fields. Our model is constructed based on measurements taken from a large number of turbines in a wind farm, as opposed to aggregating the data into a single time-series. The model incorporates both temporal and spatial characteristics of wind speed data: in addition to using a time epoch mechanism to model temporal nonstationarity, our model identifies an informative neighborhood of turbines that are spatially related, and consequently, constructs an ensemble-like predictor using the data associated with the neighboring turbines. Using actual wind data measured at 200 wind turbines in a wind farm, we found that the two modeling elements benefit short-term wind speed forecasts. We also investigate the use of regime switching to account for the effect of wind direction and the use of geostrophic wind to account for the effects of meteorologic factors other than wind. These at best provide a small performance boost to speed forecast.     

Foundations for offshore wind turbines

An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers.     

A Geodesign Method of Human-Energy-Water Interactive Systems for Urban Infrastructure Design: 10KM2 Near-Zero District Project in Shanghai

The grand challenges of climate change demand a new paradigm of urban design that takes the performance of urban systems into account, such as energy and water efficiency. Traditional urban design methods focus on the form-making process and lack performance dimensions. Geodesign is an emerging approach that emphasizes the links between systems thinking, digital technology, and geographic context. This paper presents the research results of the first phase of a larger research collaboration and proposes an extended geodesign method for a district-scale urban design to integrate systems of renewable energy production, energy consumption, and storm water management, as well as a measurement of human experiences in cities. The method incorporates geographic information system (GIS), parametric modeling techniques, and multidisciplinary design optimization (MDO) tools that enable collaborative design decision-making. The method is tested and refined in a test case with the objective of designing a near-zero-energy urban district. Our final method has three characteristics. ① Integrated geodesign and parametric design: It uses a parametric design approach to generate focal-scale district prototypes by means of a custom procedural algorithm, and applies geodesign to evaluate the performances of design proposals. ② A focus on design flow: It elaborates how to define problems, what information is selected, and what criteria are used in making design decisions. ③ Multi-objective optimization: The test case produces indicators from performance modeling and derives principles through a multi-objective computational experiment to inform how the design can be improved. This paper concludes with issues and next steps in modeling urban design and infrastructure systems based on MDO tools.     

基于CATIA二次开发的快速建模技术

在分析目前三维参数化设计技术的基础上,以飞机典型零件为建模对象,研究快速建模技术.借助CAA,以VC++作为编程工具,对CATIA进行二次开发,并对飞机零件进行交互式参数化设计.分析了CAA的组成、原理和功能.对飞机典型零件进行界面操作,分析零件的特征参数,实现参数修改和重新驱动,快速生成新的飞机零件.实例验证表明,所研究的方法能快速、自动生成飞机典型零件,实现飞机零件的快速建模,大约节省30%的建模时间,极大地提高了设计效率.     

基于自由涡尾迹方法的大型风力机动态响应和尾迹研究

针对大型风力机,在当作柔性和刚性风力机时,可以通过气动和结构耦合动力学用来研究两者尾迹和载荷的区别。在设计和校核阶段,需要考虑风力机结构载荷影响的动态特性和气动性能变化。采用非定常自由涡尾迹方法计算尾迹形状和气动载荷。在考虑气动载荷、惯性载荷和重力载荷影响下,分析了叶片挥舞和摆振动态响应。采用模态法建立起风力机解耦动力学方程,并且进行数值求解该方程。结果表明:风力机考虑柔性变形后,对尾迹形状、动态响应和气动性能产生一定影响。这种柔性和刚体风力机的差异表明气动结构耦合效应对风力机的设计和性能计算具有重要意义。     

Study on Hydraulic Transmission of Offshore Low-speed Wind Energy Generator

For offshore hydraulic drive wind turbines, the problems of unsatisfactory speed control and low efficiency at low wind speeds are targeted. A low-speed high-torque radial piston pump is designed to replace the traditional fixed pump with a particular focus on its low-speed performance. The pump is characterized by small internal leakage at low wind speeds and high volumetric efficiency, which is beneficial to improve the power generation efficiency of the system. A new linear control method based on the PID algorithm and feedforward compensation was proposed to obtain the constant speed output control of variable motor at low wind speed. With the model for wind turbine and fixed pump-variable motor main drive system, the system was simulated and experimentally proved to verify the feasibility and anti-interference performance of the system control method at low wind speeds. A promising outcome was obtained on the response characteristics of system power and efficiency at low wind speeds. This can be a powerful technical support for the normal ustility of hydraulic drive wind turbines.