基于试验设计的发动机进气系统动态优化设计

发动机进气系统噪声是车辆最主要的噪声源之一,对车内噪声影响尤其显著.基于管道声学理论,提出了发动机进气系统噪声仿真方法--无源法;基于四分之一波长管的参数化模型,研究了发动机进气系统动态优化设计方法.应用"无源法",在不具备发动机仿真模型的情况下,通过进气系统声学性能DOE分析,利用响应面法对四分之一波长管的设计参数进行优化,为进气系统声学性能设计提供依据.     

发动机进气系统声学性能动态灵敏度设计

发动机进气系统噪声是车辆最主要的噪声源之一,对车内噪声影响尤其显著。基于管道声学理论,提出了发动机进气系统噪声仿真方法——无源法;基于赫姆霍兹消声器的集中参数模型,提出了发动机进气系统声学性能动态灵敏度设计方法。应用"无源法",在不具备发动机仿真模型的情况下,仍然能进行进气系统声学性能动态灵敏度设计,通过仿真分析能够迅速准确地获得进气系统声学性能灵敏度设计信息,为进气系统声学性能优化提供依据。     

小型汽油机进气系统声学性能优化设计

随着车辆舒适性要求的不断提高,对发动机进气系统的声学性能要求也越来越高.以声学理论为基础,建立小型汽油机滤清器的参数化数值模型.首先,通过小型汽油机直管管口噪声模拟,获得进气系统插入损失的目标值;其次,结合插入损失的目标值确定小型汽油机进气系统传递损失的目标值,应用滤清器的数值模型优化滤清器的结构参数.小型汽油机进气系统声学性能优化设计方法具有很高的工程应用价值,并为滤清器的参数化设计提供了理论依据.     

燃气轮机进气系统性能仿真分析

进气系统噪声是燃气轮机主要噪声源之一。应用计算流体动力学和声学有限元法分别对燃气轮机进气空气滤清器和进气消声器的流动阻力和消声特性进行计算和分析。研究不同结构参数对进气系统空气动力性能和消声性能的影响,用于指导燃气轮机进气系统的优化设计。     

基于试验设计的发动机进气系统动态优化设计

发动机进气系统噪声是车辆最主要的噪声源之一,对车内噪声影响尤其显著。基于管道声学理论,提出了发动机进气系统噪声仿真方法——无源法;基于四分之一波长管的参数化模型,研究了发动机进气系统动态优化设计方法。应用“无源法”,在不具备发动机仿真模型的情况下,通过进气系统声学性能DOE分析,利用响应面法对四分之一波长管的设计参数进行优化,为进气系统声学性能设计提供依据。     

火炮最优射击稳定性设计研究

为获取最优的后坐阻力规律FR(t)以提高射击稳定性,基于多体系统动力学建模理论,建立了全炮动力学模型;以火炮射击时跳动量最小为目标,节制杆各圆锥段直径为设计变量,基于优化设计方法对优化问题进行了求解。优化结果表明:最大后坐阻力和火炮跳高都小于优化前,后坐阻力曲线更加平缓,火炮射击稳定性得到明显改善。     

厌氧膜生物反应器膜污染特性研究

试验研究了厌氧膜生物反应器(MCAB)在处理酒厂高浓度有机废水时的膜污染特性.试验分析了膜阻力分布状况,结果表明外部阻力(浓差极化阻力和泥饼层阻力之和)占总阻力的98%,小于膜孔的物质进入膜孔内引起堵塞与吸附而形成的内部阻力仅占总阻力的2%.同时对泥饼阻力模型(J(t)与t的关系)进行变形推导得出新的阻力模型(阻力R与t的关系),并对数据进行线性拟合,结果表明厌氧膜生物反应器膜阻力符合新的阻力模型,并得到试验条件下的厌氧膜生物反应器的阻力数学模型方程为:R(t)=2.19×1013(1 0.14t)0.5.     

基于公理设计的工业机械手设计方案评价研究

基于公理设计理论,结合工业机械手常见的设计方案组成元素,建立了工业机械手概念设计方案评价模型,实现了对工业机械手概念设计方案组进行评价并得到最优方案的推理过程.基于以上方法开发了原型系统,并以典型的工业机械手设计方案为例进行评价,验证了该理论和方法的可行性.研究表明,本文提出的基于公理设计的方案评价方法有利于设计过程的优化,其推理过程的形式化描述,便于计算机的表达和操作.该方法为工业机械手设计过程的优化做了一些有益的探索.     

基于SGS模型与AHP的侦测无人机造型设计研究

目的 为了满足无人机用户需求,完善侦测无人机造型设计方法,进一步拓展产品设计路径。方法 将管理学中的门径管理模型(SGS)融入产品系统开发设计流程;调研用户需求并结合层次分析法(AHP)构建判断矩阵,计算各个设计指标权重并排序,以此促进设计决策,完成侦测无人机造型设计方案;采用7点量表法进行初步方案设计评价,验证设计模型和过程的科学性。结论 以侦测无人机造型设计为例,通过构建SGS产品系统开发模型,运用AHP分析方法进行设计方案指标决策,为侦测无人机造型设计拓展设计路径,为相关产品的设计提供新思路。     

进气管路对固冲试验推力测量的影响

研究模拟冲压进气条件下,进气管路结构以及温度、压力、速度等进气参数变化对冲压发动机地面直连试验推力测量的影响,基于系统动力学模型在广义胡克定律意义下探讨了系统传输特性.论述了含波纹管进气接管的设计原理、方法,考虑温度、压力载荷及长度等参数变化的不同工况,利用有限元方法对波纹管进行了应力、应变、位移等计算和模态分析.依据结果分析和科研经验,给出了进气管路及进气参数变化对推力测量影响的主要作用规律,多次试验结果验证了分析的正确性.     

An Approach for Robust Design of Reactive Power Metal Mixtures Based on Non-deterministic Micro-scale Shock Simulation

In this paper, we propose a method for the robust design of materials involving processes that are computationally intensive and selectively random. The material system considered is a reactive particle metal mixture (RPMM) composed of aluminum and iron oxide (Al+Fe₂O₃). Shock simulations of discrete energetic particle mixtures are performed to predict the system’s mechanical and thermal behavior that will be used by a designer of the mixture to achieve robust micro-scale reaction initiation. The method used to predict the behavior of the material system is the robust concept exploration method with error margin index (RCEM-EMI). An error margin index is a mathematical construct indicating the location of mean system performance and the spread of this performance considering both variability in design variables and models of the system. Variability in responses of a model may be due to system variation that cannot be easily parameterized in terms of noise factors. Furthermore, lack of data, due to the cost of simulations and experiments, leads to uncertain parameters in empirical models. System response variability and parameter uncertainty in an empirical model are estimated in a computationally efficient manner to formulate the error margin indices, which are then leveraged to search for ranged sets of design specifications. Finally, the RCEM-EMI is illustrated for designing a RPMM.     

设计科学研究方法探讨

目的 智能时代的设计学研究正面临创新和转型,探索设计科学的研究方法、开拓学科交叉融合的路径、创新人才培养的新范式、传播中国文化核心价值观、赋能中国特色设计理论的创新和发展是智能时代设计学研究的新目标.方法 以文献研究为导向,实证研究为基础,运用计量、大数据挖掘、信息可视化分析、知识图谱对本体论进行定量研究;采用科学实验的生理信号识别验证方法的可行性.结论 以用户为中心的设计研究方法具有很强的有效性,基于可用性测试的模糊综合评价模型,可以量化用户体验,获得有效精准的用户数据;设计科学方法是创造性、科学性、艺术性的多学科交叉的系统设计整合方法.     

Performance of die cooling system design in hot stamping process

This study examined the cooling channel design of hot stamping tools to provide an effective method for the cooling system design. A flat plate tool model was investigated to determine the effects of cooling channel and manufacturing parameters on the cooling rate and cooling uniformity of the sheet blank by conducting finite element analysis. The fractional factor method was also employed to establish empirical equations for describing the cooling performance of the flat plate model. The empirical equations established in the present study can efficiently predict the cooling rate and cooling uniformity of sheet blanks with various cooling channel designs, and are of much help in providing an initial cooling system design for hot stamping tools. To validate the accuracy of the finite element analysis, experiments on sheet blank cooling process were conducted using the proposed flat plate tool design. The cooling processes were cyclically repeated for the validation of blank temperature distribution. The temperature evolution of sheet blanks obtained from the finite element simulations agree well with the experimental results and the validity of the finite element model is confirmed, and thus the effectiveness of the empirical equations is established.     

Accelerated Life Testing (ALT) Design Based on Computational Reliability Analysis

Accelerated life testing (ALT) design is usually performed based on assumptions of life distributions, stress–life relationship, and empirical reliability models. Time‐dependent reliability analysis on the other hand seeks to predict product and system life distribution based on physics‐informed simulation models. This paper proposes an ALT design framework that takes advantages of both types of analyses. For a given testing plan, the corresponding life distributions under different stress levels are estimated based on time‐dependent reliability analysis. Because both aleatory and epistemic uncertainty sources are involved in the reliability analysis, ALT data is used in this paper to update the epistemic uncertainty using Bayesian statistics. The variance of reliability estimation at the nominal stress level is then estimated based on the updated time‐dependent reliability analysis model. A design optimization model is formulated to minimize the overall expected testing cost with constraint on confidence of variance of the reliability estimate. Computational effort for solving the optimization model is minimized in three directions: (i) efficient time‐dependent reliability analysis method; (ii) a surrogate model is constructed for time‐dependent reliability under different stress levels; and (iii) the ALT design optimization model is decoupled into a deterministic design optimization model and a probabilistic analysis model. A cantilever beam and a helicopter rotor hub are used to demonstrate the proposed method. The results show the effectiveness of the proposed ALT design optimization model. Copyright © 2015 John Wiley & Sons, Ltd.     

抛弃式光纤温深仪系统设计与实现

海水温度梯度是海洋调查、海洋研究的重要参数，抛弃式温度剖面测量系统（Expendable Bathy Thermograph，XBT）是一种可在测量船走航状态下进行海洋温度剖面测量的仪器，具有实时、快速和低成本的特点。传统XBT通常不使用深度传感器，而是根据探头入水时间利用经验公式推算所处深度，深度误差较大。文章介绍了抛弃式光纤温深仪系统的原理、设计与实现，对研制的样机和探头进行了测试和数据分析，实现了对温度、深度的实时快速直接测量，测量误差较小，为以后抛弃式光纤温深仪系统的深入研究提供了参考依据。     

Development of computer program for simulation of an ice bank system operation, Part I: Mathematical modelling

Since the use of standard engineering methods in the process of an ice bank performance evaluation offers neither adequate flexibility nor accuracy, the aim of this research was to provide a powerful tool for an industrial design of an ice storage system allowing to account for the various design parameters and system arrangements over a wide range of time varying operating conditions. In this paper the development of a computer application for the prediction of an ice bank system operation is presented. Static, indirect, cool thermal storage systems with external ice on coil building/melting were considered. The mathematical model was developed by means of energy and mass balance relations for each component of the system and is basically divided into two parts, the model of an ice storage system and the model of a refrigeration unit. Heat transfer processes in an ice silo were modelled by use of empirical correlations while the performance of refrigeration unit components were based on manufacturers data. Programming and application design were made in Fortran 95 language standard. Input of data is enabled through drop down menus and dialog boxes, while the results are presented via figures, diagrams and data (ASCII) files. In addition, to demonstrate the necessity for development of simulation program a case study was performed. Simulation results clearly indicate that no simple engineering methods or rule of thumb principles could be utilised in order to validate performance of an ice bank system properly.     

System model identification of a Fabry-Perot fiber optic sensingsystem

A Fabry-Perot fiber optic temperature sensing system is presented in this paper. It uses a Fabry-Perot interferometer (FPI) to transform the environmental temperature into modulated reflected light. This light is directed to a patented light cross-correlator that locates the position of the maximum interference fringe intensity, which is detected by a linear CCD array. Therefore, the actual observed data is the position of the CCD pixel detecting the maximum interference fringe intensity rather than the light intensity itself. Consequently, this sensing mechanism is tolerant to the loss of light power that may result from external effects. Based on an analysis of the entire sensing system, a theoretical dynamic model was developed, which shows that the system dynamic response depends on the heat transfer process in the sensor head and the signal processing in the signal conditioner. An experimental method was developed to validate the theoretical model. Two empirical dynamic models are also obtained from the experimental data. Comparing the theoretical model with the empirical models, the poles result from the heat transfer process in the sensor head     

A design method of thermoelectric coolerConception d'un refroidisseur thermoélectrique

A system design method of thermoelectric cooler is developed in the present study. The design calculation utilizes the performance curve of the thermoelectric module that is determined experimentally. An automatic test apparatus was designed and built to illustrate the testing. The performance test results of the module are used to determine the physical properties and derive an empirical relation for the performance of thermoelectric module. These results are then used in the system analysis of a thermoelectric cooler using a thermal network model. The thermal resistance of heat sink is chosen as one of the key parameters in the design of a thermoelectric cooler. The system simulation shows that there exists a cheapest heat sink for the design of a thermoelectric cooler. It is also shown that the system simulation coincides with experimental data of a thermoelectric cooler using an air-cooled heat sink with thermal resistance 0.2515°C/W. An optimal design of thermoelectric cooler at the conditions of optimal COP is also studied. The optimal design can be made either on the basis of the maximum value of the optimal cooling capacity, or on the basis of the best heat sink technology available.     

基于改进FMEA的适老化智能药盒交互设计研究

目的 基于适老化智能药盒交互失效模式的数据,对智能药盒的交互模式进行优化设计,提升交互体验,有效降低交互差错率。方法 首先,成立改进FMEA专家小组进行系统性人因错误减少和预测方法分析（Systematic Human Error Reduction and Prediction Approach, SHERPA）;其次,构建智能药盒交互失误预防模型,然后对适老化智能药盒交互设计进行改进失效模式与效应分析（FailureModeand Effects Analysis, FMEA）;最后,针对需要改进的失效模式对智能药盒进行设计优化。结果 实验结果显示“实证对象”存在诸多交互失效模式,对相应交互失效模式进行优化,可有效提升老年人操作智能药盒的交互体验。结论 运用改进FMEA的方法,可以具体量化适老化智能药盒交互失效模式数据,对应失效模式数据的智能药盒交互优化设计,是可行有效的,能够有效降低老年人的用药风险,此方法可为产品交互设计研究提供新的方法路径。