Rolling stock manufacturers are finding structural solutions to reduce power required by the vehicles,and the lightweight design of the car body represents a possible solution.Optimization processes and innovative mat...Rolling stock manufacturers are finding structural solutions to reduce power required by the vehicles,and the lightweight design of the car body represents a possible solution.Optimization processes and innovative materials can be combined in order to achieve this goal.In this framework,we propose the redesign and optimization process of the car body roof for a light rail vehicle,introducing a sandwich structure.Bonded joint was used as a fastening system.The project was carried out on a single car of a modern tram platform.This preliminary numerical work was developed in two main steps:redesign of the car body structure and optimization of the innovated system.Objective of the process was the mass reduction of the whole metallic structure,while the constraint condition was imposed on the first frequency of vibration of the system.The effect of introducing a sandwich panel within the roof assembly was evaluated,focusing on the mechanical and dynamic performances of the whole car body.A mass saving of 63%on the optimized components was achieved,corresponding to a 7.6%if compared to the complete car body shell.In addition,a positive increasing of 17.7%on the first frequency of vibration was observed.Encouraging results have been achieved in terms of weight reduction and mechanical behaviour of the innovated car body.展开更多
Creating proper B-spline surface models is a very challenging task for designers in car-body surface design.Due to the tensor-product structure of B-spline surface,some undesirable issues of the redundant control poin...Creating proper B-spline surface models is a very challenging task for designers in car-body surface design.Due to the tensor-product structure of B-spline surface,some undesirable issues of the redundant control points addition,incomplete surface definition and the difficulty of trimming boundary alteration frequently occur,when designing the car-body surface with B-spline surfaces in local-feature-lines construction,full-boundary-merging and visual surface trimming.A more efficient approach is proposed to design the car-body surface by replacing B-spline surface with classical T-spline surface.With the local refinability and multilateral definition offered by Tspline surface,those designing issues related with B-spline surface can be overcomed.Finally,modeling examples of the door,hood and rear-window are given to demonstrate the advantage of T-spline surface over B-spline surface in car-body surface design.展开更多
为了解决板料成形中起皱和拉裂的问题,以某汽车挡泥板为研究对象,基于Design-exper软件,建立了摩擦系数、压边力、拉延筋阻力系数与板料拉裂、起皱之间关系的数学模型。并利用该软件进行了多目标优化,得到了最佳的参数组合:摩擦系数为0....为了解决板料成形中起皱和拉裂的问题,以某汽车挡泥板为研究对象,基于Design-exper软件,建立了摩擦系数、压边力、拉延筋阻力系数与板料拉裂、起皱之间关系的数学模型。并利用该软件进行了多目标优化,得到了最佳的参数组合:摩擦系数为0.13,压边力为350 k N,拉延筋阻力系数为35%。通过有限元模拟和生产实践验证,证明了该方法的可行的。展开更多
嵌合抗原受体T(chimeric antigen receptor T cells,CAR-T)细胞已从实验室走向了临床试验,在治疗B细胞恶性肿瘤中取得了显著疗效,但在探索CAR-T细胞治疗恶性肿瘤的临床研究中,仍面临不少困难与挑战:难以找到肿瘤特异性的靶点,以克服其...嵌合抗原受体T(chimeric antigen receptor T cells,CAR-T)细胞已从实验室走向了临床试验,在治疗B细胞恶性肿瘤中取得了显著疗效,但在探索CAR-T细胞治疗恶性肿瘤的临床研究中,仍面临不少困难与挑战:难以找到肿瘤特异性的靶点,以克服其脱靶效应(on-target off tumor effect);在治疗实体瘤中CAR-T细胞很难达到肿瘤部位,以改善免疫抑制微环境发挥作用;CAR-T细胞在清除肿瘤细胞的同时也会杀伤表达相同靶点的正常细胞;针对除B细胞肿瘤之外的血液肿瘤以及实体瘤而言,CAR-T细胞的有效性还有待提高。本文重点介绍如何通过CAR-T细胞结构的优化使得CAR-T细胞能够精准地识别肿瘤细胞,克服肿瘤的免疫抑制微环境来提高CAR-T细胞治疗恶性肿瘤的有效性;同时使得CAR-T细胞可以被更好地控制,使得CAR-T细胞的安全性更高。展开更多
文摘Rolling stock manufacturers are finding structural solutions to reduce power required by the vehicles,and the lightweight design of the car body represents a possible solution.Optimization processes and innovative materials can be combined in order to achieve this goal.In this framework,we propose the redesign and optimization process of the car body roof for a light rail vehicle,introducing a sandwich structure.Bonded joint was used as a fastening system.The project was carried out on a single car of a modern tram platform.This preliminary numerical work was developed in two main steps:redesign of the car body structure and optimization of the innovated system.Objective of the process was the mass reduction of the whole metallic structure,while the constraint condition was imposed on the first frequency of vibration of the system.The effect of introducing a sandwich panel within the roof assembly was evaluated,focusing on the mechanical and dynamic performances of the whole car body.A mass saving of 63%on the optimized components was achieved,corresponding to a 7.6%if compared to the complete car body shell.In addition,a positive increasing of 17.7%on the first frequency of vibration was observed.Encouraging results have been achieved in terms of weight reduction and mechanical behaviour of the innovated car body.
文摘Creating proper B-spline surface models is a very challenging task for designers in car-body surface design.Due to the tensor-product structure of B-spline surface,some undesirable issues of the redundant control points addition,incomplete surface definition and the difficulty of trimming boundary alteration frequently occur,when designing the car-body surface with B-spline surfaces in local-feature-lines construction,full-boundary-merging and visual surface trimming.A more efficient approach is proposed to design the car-body surface by replacing B-spline surface with classical T-spline surface.With the local refinability and multilateral definition offered by Tspline surface,those designing issues related with B-spline surface can be overcomed.Finally,modeling examples of the door,hood and rear-window are given to demonstrate the advantage of T-spline surface over B-spline surface in car-body surface design.
文摘为了解决板料成形中起皱和拉裂的问题,以某汽车挡泥板为研究对象,基于Design-exper软件,建立了摩擦系数、压边力、拉延筋阻力系数与板料拉裂、起皱之间关系的数学模型。并利用该软件进行了多目标优化,得到了最佳的参数组合:摩擦系数为0.13,压边力为350 k N,拉延筋阻力系数为35%。通过有限元模拟和生产实践验证,证明了该方法的可行的。
文摘嵌合抗原受体T(chimeric antigen receptor T cells,CAR-T)细胞已从实验室走向了临床试验,在治疗B细胞恶性肿瘤中取得了显著疗效,但在探索CAR-T细胞治疗恶性肿瘤的临床研究中,仍面临不少困难与挑战:难以找到肿瘤特异性的靶点,以克服其脱靶效应(on-target off tumor effect);在治疗实体瘤中CAR-T细胞很难达到肿瘤部位,以改善免疫抑制微环境发挥作用;CAR-T细胞在清除肿瘤细胞的同时也会杀伤表达相同靶点的正常细胞;针对除B细胞肿瘤之外的血液肿瘤以及实体瘤而言,CAR-T细胞的有效性还有待提高。本文重点介绍如何通过CAR-T细胞结构的优化使得CAR-T细胞能够精准地识别肿瘤细胞,克服肿瘤的免疫抑制微环境来提高CAR-T细胞治疗恶性肿瘤的有效性;同时使得CAR-T细胞可以被更好地控制,使得CAR-T细胞的安全性更高。
