应用JSTAMP/NV的热成形案例仿真

以国际板材成形数值模拟会议(Numisheet2008)上提出的汽车B柱热成形考题为例,论述了JSTAMP/NV在热成形中的应用过程,并将仿真结果与实验结果进行了对比,结果表明:仿真结果与实验结果基本吻合,精确地预测出该件的板料厚度分布和成形后的硬度值。最后,对JSTAMP/NV在热成形中的分析流程进行了总结。     

JSTAMP/NV2.6新增功能介绍

详细论述了JSTAMP/NV2.6版新增功能及其应用方法。     

Effect of the Nanodiamond Host on a Nitrogen‐Vacancy Color‐Centre Emission State

Control over the quantum states of individual luminescent nitrogen‐vacancy (NV) centres in nanodiamonds (NDs) is demonstrated by careful design of the crystal host: its size, surface functional groups, and interfacing substrate. By progressive etching of the ND host, the NV centres are induced to switch from latent, through continuous, to intermittent or “blinking” emission states. The blinking mechanism of the NV centre in NDs is elucidated and a qualitative model proposed to explain this phenomenon in terms of the centre electron(s) tunnelling to acceptor site(s). These measurements suggest that the substrate material and its proximity to the NV are responsible for the fluorescence intermittency.     

材料力学性能参数对薄板拉伸件成形性能的影响

拉伸成形是冲压件最重要的成形方式之一,研究材料力学性能参数对其拉伸成形性能的影响则显得至关重要。本文应用材料冲压成形有限元分析软件JSTAMP/NV对燃气灶壳体的拉伸成形过程进行模拟,研究了金属材料的屈服应力,加工硬化指数、厚向异性系数、公称拉伸强度对冲压件成形性能指标的影响。     

N对V-微合金化钢15MnVq的组织和性能的影响

通过100 kg真空感应炉,分别添加V-N合金和V-Fe合金熔炼成15MnVNq钢(%-0.15C、1.71Mn、0.11V、0.019 ON)和15MnVq钢(%:0.15C、1.72Mn、0.11V、0.003 3N),并轧制成14 mm钢板.试验结果表明,15MnVq钢中加入0.019%的N促进V(C,N)析出和明显细化钢的组织,钢的屈服和抗拉强度分别由393 MPa和578 MPa提高至510 MPa和660 MPa,-20℃冲击功AKV由21.9 J提高到101.8 J;同时加N后明显降低了15MnVq钢的时效敏感性.     

基于JSTAMP/NV的U形冲压件弯曲回弹分析

简介JSTAMP/NV的主要功能和吉田-上森材料模型（Y-U模型）,以2011年国际板材成形数值模拟会议（Numisheet’2011）上提出的预应变对U形冲压件弯曲回弹影响的考题为例,介绍在板料有、无加载预应变情况下用JSTAMP/NV进行弯曲成形回弹仿真的应用过程,并将回弹仿真结果与试验结果进行比较,结果表明仿真结果与试验结果吻合良好.最后简介JSTAMP/NV最新版本2.6的新增功能.     

基于JSTAMP/NV和HEEDS的汽车前纵梁冲压工艺优化分析

为优化高强度钢汽车构件的冲压工艺并精确预测其回弹情况,以2011年国际板材成形数值模拟会议（Numisheet’ 2011）上提出的基于CAE的汽车前纵梁冲压工艺优化考题为例,介绍用JSTAMP/NV和HEEDS对汽车前纵梁进行拉深成形和回弹仿真及其工艺参数优化的应用过程,并将采用最优化工艺参数进行仿真获取的回弹结果与实验结果进行比较,结果表明仿真结果与实验结果吻合良好.     

基于JSTAMP/NV的中厚板冲压回弹分析

由于中厚板在冲压成型过程中的应力分布特点与常规薄板冲压有所不同,因此以JSTAMP/NV提供的解决方案为例,探讨中厚板回弹分析中单元类型和材料模型等关键参数的设定.利用JSTAMP/NV提供的解决方案对料厚为7 mm的某铁路货车梁进行回弹仿真,并使用专用于中厚板回弹分析的参数设定,结果表明仿真结果与试验结果吻合良好。     

Global and local heat transfer analysis for bicycle helmets using thermal head manikins

Predicting thermal comfort of protective headgear is of particular interest since the head is one of the most heat-sensitive body parts. Thermal head manikins enable systematic investigation of heat transfer properties of headgear. Such investigation provides valuable inputs for the development of new helmet concepts to improve thermal comfort.This study presents a nine-zone thermal head manikin (9zM) to evaluate local heat transfer effects of headgear. Performance of the new manikin and local data were assessed by comparing with data from a two-zone thermal head manikin (2zM) published previously. Variation for heat flux data was found to be lower for 9zM than for 2zM in tests including convective and radiative heat transfer. The calculation of radiant heat gain revealed similar variation at cranial section for both manikins but it increased at facial section for 9zM. Classification of helmets based on heat transfer data differed for head manikins likely due to slight differences in head geometries. Moreover, local heat transfer data obtained from the 9zM allowed a more detailed investigation of headgear properties. This knowledge contributes to a better understanding of the thermal interaction of head and headgear and, therefore, to a more justified development of optimised headgear designs.     

基于资源拆分的虚拟网络功能服务链映射算法

针对网络虚拟化环境下虚拟网络功能服务链的资源分配以及部署问题,提出了基于资源拆分的虚拟网络功能服务链部署策略。通过对租户的资源需求进行主动拆分,利用更小的资源分配粒度达到提高物理资源利用率的目的。利用最优化理论将虚拟网络功能服务链的资源分配问题建模成具有链式拓扑结构的虚拟网络映射问题,并通过设计高效的启发式算法以有效地解决这一问题。实验结果表明,该算法与其它虚拟网络映射算法相比,能有效提高物理资源的利用率以及租户请求的接收率。