Virtual product development (VPD) is essentially based on simulation. Due tocomputational inefficiency, traditional engineering simulation software and optimization methods areinadequate to analyze optimization proble...Virtual product development (VPD) is essentially based on simulation. Due tocomputational inefficiency, traditional engineering simulation software and optimization methods areinadequate to analyze optimization problems in VPD. Optimization method based on simulationmetamodel for virtual product development is proposed to satisfy the needs of complex optimaldesigns driven by VPD. This method extends the current design of experiments (DOE) by variousmetamodeling technologies. Simulation metamodels are built to approximate detailed simulation codes,so as to provide link between optimization and simulation, or serve as a bridge for simulationsoftware integration among different domains. An example of optimal design for composite materialstructure is used to demonstrate the newly introduced method.展开更多
An integrated template of virtual product development alters primarilysequential tradition mode of product life cycle. The template integrates all processes of productdevelopment using digital modem. An environment of...An integrated template of virtual product development alters primarilysequential tradition mode of product life cycle. The template integrates all processes of productdevelopment using digital modem. An environment of virtual product development provides productdevelopment environment of integration, communion, network, concurrent and collaboration. Combiningdevelopment of new rapier loom, an innovated design process is researched in virtual productdevelopment, which consists three portions: constructing an integration development environment,innovation design and manufacturing simulation. The innovated design process realizes reversedesign, mechanism concept design, structural design and analysis, performance analysis andmanufacturing process simulation of virtual product, which can enhance greatly product performanceand reduce cost and development cycle of new product.展开更多
To establish a proper evaluation method for spatial cognitive deficits and a form of developmental disorder, we have used an immersive virtual reality (VR) device to develop a game that involves actually walking throu...To establish a proper evaluation method for spatial cognitive deficits and a form of developmental disorder, we have used an immersive virtual reality (VR) device to develop a game that involves actually walking through a VR space to search for a target object. In this paper, we presented the results of control experiment with 22 healthy elementary school students as participants. The complexity of the VR space was controlled according to the number of pillars present and whether an overall view was possible (controlled by the height of the pillars). For each set of conditions, 24 trials were performed, and the route and time taken to search for the target were recorded. The starting point was changed in each subsequent trial. Results showed that the search time decreased as the number of trials increase, suggesting a process whereby a cognitive map was formed. We also compared the present results to results from our previous experiment with university students using the same experimental conditions, and we discussed the influence of developmental stage on spatial cognition.展开更多
Some concepts of virtual product are discussed. The key technologies ofvirtual fuel-pump development are in detail analysed, which include virtual fuel-pump productmodeling, intelligent simulation, distributed design ...Some concepts of virtual product are discussed. The key technologies ofvirtual fuel-pump development are in detail analysed, which include virtual fuel-pump productmodeling, intelligent simulation, distributed design environment, and virtual assembly. The virtualfuel-pump development prototype system considers requirement analysis, concept design, injectionpreferment analysis, detailed design, and assembly analysis.展开更多
As the simulation quality increases, the determination of hot spots is not enough to foundry engineers anymore. The simulation results have to fit in a quality way into the real foundry world. More and more results of...As the simulation quality increases, the determination of hot spots is not enough to foundry engineers anymore. The simulation results have to fit in a quality way into the real foundry world. More and more results of the simulation will be used to optimise the casting process. Here it is necessary to have a very precise knowledge of the physical data. as well as the description of the geometry. To make use of the simulation in especially the magnesium-casting development it is necessary to work with precise geometrical, physical and numerical models. In this paper we describe the development of physical data concerning the heat transfer during filling and solidification by different casting methods. The low pressure as well as the gravity die casting method are used to get real data to find out the right conditions in the simulation in order to simulate the real behaviour during production. Practical tests are done under different test conditions to develop the right physical data as well as the right conditions in the metal-mould interface. The different surface conditions and the influence of the die and the molten metal temperatures are important for the layout of the die casting process. Three different shapes were applied to different mould materials and casting methods. The cooling conditions are tested on specific items. The cooling shape is not restricted by the drilling conditions. The effect of different cooling conditions are generated and measured. The results form the basis for the heat transfer conditions. These results are applied to real castings, cellular phone housings by low-pressure die casting process. The use of the new conditions leads to a good process description.展开更多
[目的]介绍虚拟现实技术辅助儿童发育性髋脱位(developmental dislocation of the hip,DDH)Salter截骨术的技术与初步临床结果。[方法]对46例(46髋)DDH患儿术前进行计算机虚拟现实辅助Salter截骨术。术前CT扫描建立虚拟髋关节模型,模拟S...[目的]介绍虚拟现实技术辅助儿童发育性髋脱位(developmental dislocation of the hip,DDH)Salter截骨术的技术与初步临床结果。[方法]对46例(46髋)DDH患儿术前进行计算机虚拟现实辅助Salter截骨术。术前CT扫描建立虚拟髋关节模型,模拟Salter截骨术,观察手术效果,确认股骨头包容良好,实际手术中按模拟手术测量参数进行操作。行患侧Bikini切口,沿着髂嵴软骨外缘近端切开,清理髋臼,剥离髂骨,经股骨近端外侧做股骨转子间截骨,按照术前模拟确定的髋臼最佳旋转角旋转插入合适的自体或异体骨块,克氏针固定后复位髋臼,修剪关节囊,逐层缝合。[结果]患儿均顺利完成手术,手术时间(52.33±7.52)min,术中失血量(45.35±5.01)ml,术后住院(7.20±1.55)d;术中及术后无严重并发症。患儿术后随访6~18个月,平均(10.35±3.01)个月,末次随访时,所以患儿均可自行下地活动,McKay功能评价优良率为100%。影像方面,虚拟手术与真实手术后髋臼指数(acetabular index,AI)、中心边缘角(centre-edge,CE)、前倾角均显著低于术前相应参数(P<0.05)。虚拟手术与真实手术后的AI、CE角、前倾角差异无统计学意义(P>0.05)。[结论]采用虚拟现实技术辅助Salter截骨术可提升治疗儿童DDH的精准性。展开更多
基金National Natural Science Foundation of China (No.5988950)
文摘Virtual product development (VPD) is essentially based on simulation. Due tocomputational inefficiency, traditional engineering simulation software and optimization methods areinadequate to analyze optimization problems in VPD. Optimization method based on simulationmetamodel for virtual product development is proposed to satisfy the needs of complex optimaldesigns driven by VPD. This method extends the current design of experiments (DOE) by variousmetamodeling technologies. Simulation metamodels are built to approximate detailed simulation codes,so as to provide link between optimization and simulation, or serve as a bridge for simulationsoftware integration among different domains. An example of optimal design for composite materialstructure is used to demonstrate the newly introduced method.
基金This project is supported by National 863 Foundation of China (No. 863-511-030-003).
文摘An integrated template of virtual product development alters primarilysequential tradition mode of product life cycle. The template integrates all processes of productdevelopment using digital modem. An environment of virtual product development provides productdevelopment environment of integration, communion, network, concurrent and collaboration. Combiningdevelopment of new rapier loom, an innovated design process is researched in virtual productdevelopment, which consists three portions: constructing an integration development environment,innovation design and manufacturing simulation. The innovated design process realizes reversedesign, mechanism concept design, structural design and analysis, performance analysis andmanufacturing process simulation of virtual product, which can enhance greatly product performanceand reduce cost and development cycle of new product.
文摘To establish a proper evaluation method for spatial cognitive deficits and a form of developmental disorder, we have used an immersive virtual reality (VR) device to develop a game that involves actually walking through a VR space to search for a target object. In this paper, we presented the results of control experiment with 22 healthy elementary school students as participants. The complexity of the VR space was controlled according to the number of pillars present and whether an overall view was possible (controlled by the height of the pillars). For each set of conditions, 24 trials were performed, and the route and time taken to search for the target were recorded. The starting point was changed in each subsequent trial. Results showed that the search time decreased as the number of trials increase, suggesting a process whereby a cognitive map was formed. We also compared the present results to results from our previous experiment with university students using the same experimental conditions, and we discussed the influence of developmental stage on spatial cognition.
基金National Natural Science Founda-tion of China (No. 59889505).
文摘Some concepts of virtual product are discussed. The key technologies ofvirtual fuel-pump development are in detail analysed, which include virtual fuel-pump productmodeling, intelligent simulation, distributed design environment, and virtual assembly. The virtualfuel-pump development prototype system considers requirement analysis, concept design, injectionpreferment analysis, detailed design, and assembly analysis.
文摘As the simulation quality increases, the determination of hot spots is not enough to foundry engineers anymore. The simulation results have to fit in a quality way into the real foundry world. More and more results of the simulation will be used to optimise the casting process. Here it is necessary to have a very precise knowledge of the physical data. as well as the description of the geometry. To make use of the simulation in especially the magnesium-casting development it is necessary to work with precise geometrical, physical and numerical models. In this paper we describe the development of physical data concerning the heat transfer during filling and solidification by different casting methods. The low pressure as well as the gravity die casting method are used to get real data to find out the right conditions in the simulation in order to simulate the real behaviour during production. Practical tests are done under different test conditions to develop the right physical data as well as the right conditions in the metal-mould interface. The different surface conditions and the influence of the die and the molten metal temperatures are important for the layout of the die casting process. Three different shapes were applied to different mould materials and casting methods. The cooling conditions are tested on specific items. The cooling shape is not restricted by the drilling conditions. The effect of different cooling conditions are generated and measured. The results form the basis for the heat transfer conditions. These results are applied to real castings, cellular phone housings by low-pressure die casting process. The use of the new conditions leads to a good process description.
文摘[目的]介绍虚拟现实技术辅助儿童发育性髋脱位(developmental dislocation of the hip,DDH)Salter截骨术的技术与初步临床结果。[方法]对46例(46髋)DDH患儿术前进行计算机虚拟现实辅助Salter截骨术。术前CT扫描建立虚拟髋关节模型,模拟Salter截骨术,观察手术效果,确认股骨头包容良好,实际手术中按模拟手术测量参数进行操作。行患侧Bikini切口,沿着髂嵴软骨外缘近端切开,清理髋臼,剥离髂骨,经股骨近端外侧做股骨转子间截骨,按照术前模拟确定的髋臼最佳旋转角旋转插入合适的自体或异体骨块,克氏针固定后复位髋臼,修剪关节囊,逐层缝合。[结果]患儿均顺利完成手术,手术时间(52.33±7.52)min,术中失血量(45.35±5.01)ml,术后住院(7.20±1.55)d;术中及术后无严重并发症。患儿术后随访6~18个月,平均(10.35±3.01)个月,末次随访时,所以患儿均可自行下地活动,McKay功能评价优良率为100%。影像方面,虚拟手术与真实手术后髋臼指数(acetabular index,AI)、中心边缘角(centre-edge,CE)、前倾角均显著低于术前相应参数(P<0.05)。虚拟手术与真实手术后的AI、CE角、前倾角差异无统计学意义(P>0.05)。[结论]采用虚拟现实技术辅助Salter截骨术可提升治疗儿童DDH的精准性。
