基于Abaqus的发动机主轴承壁仿真方法

为得到发动机轴承载荷,用EXCITE PU软件对某发动机的曲轴进行仿真,计算得到轴承的EHD力,并根据轴承受力和力矩的情况,选取相应的危险曲轴转角,将对应转角下的曲轴轴承载荷映射到有限元网格上,进一步使用Abaqus对主轴承壁进行强度和疲劳分析.     

枪管强度的理论计算与数值计算的误差分析

针对现有文献对枪管强度计算的误差分析缺乏研究的问题,笔者将给出枪管强度计算的误差来源及提高求解精度的方法。笔者基于Abaqus软件对某枪管强度进行数值计算,并采用最大线应变准则、最大切应力准则和第四强度理论进行计算,将理论计算结果与仿真结果进行对比,并给出了离散误差和数值误差对计算结果的影响。仿真结果表明：采用第四强度理论作为枪管设计和校核的理论依据较为合理,采用C3D8I单元类型计算结果比C3D8R单元类型计算结果更加逼近第四强度理论计算结果。     

部分熔透焊与填角焊区域过焊孔开设方式

针对海洋工程建造过程中对过焊孔端部缝隙采用包角处理导致包角处的过焊孔边缘不光滑,易产生集中的现象,对比规范要求,提出针对该问题的全熔透过渡和变通包角两种不同的处理方法,并通过现场试焊和有限元分析模拟的方式检验新提出方法的可行性。所提出的两种方法可为后续项目提供该类型问题的解决思路。     

Experimental and computational investigations into creep response of AFRP reinforced timber beams

In the past two decades, several attempts have been made to strengthen and stiffen timber beams by reinforcing them with layers of fibre-reinforced polymer (FRP) composites, oriented in various configurations. This paper describes an experimental and numerical investigation into the short-term and creep performance of southern yellow pine (SYP) and Douglas-fir (DF) timber beams strengthened by unidirectional aramid fibre-reinforced polymer sheet (AFRP). The creep parameters of AFRP and plain wood were determined using in-house creep tests. Accordingly, a non-linear finite element model was developed to predict the creep response of the AFRP reinforced timber beams based on the creep characteristics of the individual components. The results of the finite element analysis showed a good agreement with the experimental results conducted on the AFRP reinforced samples. Moreover, the influence of reinforcement on the flexural strength of reinforced beams was also examined. It could be concluded that enhancement of the timber beams with AFRP reinforcements provides improvement to both strength and stiffness, and can also effectively reduce the creep deformation of wooden beams.     

基于有限元仿真的手机超薄透明翻盖结构设计研究

跌落试验是手机产品环境实验的一个重要测试项目，其一般在产品开发后期进行，属于实物实验。采用有限元仿真，可以在实物样机出现前进行，能有效发现设计缺陷，提高产品开发速度。运用HyperMesh和Abaqus软件进行手机跌落仿真，得到手机超薄透明翻盖在不同工况跌落时的应力应变情况，通过与许用应力应变比较，分析翻盖在跌落时的可靠性，并与实际的手机跌落试验进行比较，验证了仿真分析的准确性，并确认了透明翻盖结构设计的合理性。     

芯辊进给速度对环件冷辗扩工艺的影响规律研究

基于Abaqus/Explicit提供的显式动力学有限元算法,对矩形截面环件冷辗扩进行了有限元数值模拟,揭示了芯辊进给速度对环件冷辗扩过程中环件端面质量、轴向宽展率、辗扩力、辗扩力矩以及金属流动特性的影响规律,并从金属塑性成形原理和塑性加工力学等角度对这些规律进行了合理的解释,从而获得了进给速度对冷辗扩成形的影响规律,为环件冷辗扩在实际应用中进给速度的选择提供了依据,对揭示冷辗扩成形机理也具有十分重要的意义。     

Effect of transient trapping on hydrogen transport near a blunting crack tip

The paper revisits the way transient trapping is introduced in the literature based on the Sofronis and McMeeking model (Sofronis and McMeeking, 1989) [1] of hydrogen transport. It is shown that the direct use of the improved formulation made by Krom et al. (1999) [2] for transient trapping may lead to non-physical results of hydrogen concentration in case of an insulated system. The use of McNabb and Foster trapping kinetic equation is more relevant, and its ability to model both trap creation and kinetic trapping is investigated on a Small Scale Yielding configuration for the sake of comparison with a reference case from the literature. A parametric study is conducted, exhibiting differences with literature, and emphasizes on the significant effect of trapping kinetics on the hydrogen distribution.     

基于Abaqus子模型技术分析透平空心叶片气膜孔应力

燃机透平空心冷却叶片的结构异常复杂,叶身表面数量众多,尺寸小巧的气膜孔给应力,计算带来巨大困难。要准确的计算叶身应力,其计算规模将非常巨大,需要消耗大量的计算机资源才能完成。子模型技术通过对几何模型的分解,在保证总体计算规模不太大的同时又可以保证重点部位的计算精度。本研究用Abaqus商业软件的子模型方法分析气膜孔周围应力分布,比较了传统计算方法和子模型方法的计算精度、时间和资源消耗量。     

CVD法制备6.5%Si硅钢过程中的微观结构对硅扩散的影响研究

目的 研究渗硅过程中的晶界占比对渗硅质量的影响,从而探究出制备6.5％Si硅钢的合理工艺.方法 通过CVD法,利用真空管式炉制备6.5％Si硅钢.通过高温金相实验探究温度对晶粒尺寸的影响,利用高温与常温下的金相实验、扫描电镜(SEM)和能谱分析(EDS)分别统计平均晶粒尺寸、平均晶界宽度和扩散方向上晶粒内部与晶界上的硅含量,再利用MATLAB和Abaqus软件求解扩散系数和模拟分析微观渗硅.结果 1200℃下反应60 s,再扩散至140 s时,平均晶粒尺寸为140.45μm,平均晶界宽度为76.31 nm,由实验数据计算得到的晶粒内部扩散系数为9.026×10–6 mm2/s,晶界扩散系数为2.924×10–3 mm2/s,晶界占比为0.163％.结论 晶界会影响渗硅扩散的速率与时间,晶界占总体积的比例越高,硅扩散越快,但相同时间内扩散越不均匀,导致硅钢片塑性下降.