采煤机导向滑靴磨损模拟试验分析

基于修正Archard模型,将导向滑靴磨损过程等效为若干个磨损周期累积作用的结果,提出一种导向滑靴磨损的有限元分步模拟试验法,分析采煤机牵引速度、煤岩坚固性系数对导向滑靴磨损影响趋势,建立导向滑靴磨损深度预测模型。结果表明,上导向面磨损剧烈,牵引速度、煤岩坚固性系数越大,导向滑靴磨损越严重。导向滑靴磨损深度预测模型可为其维修、更换提供参考。

桥梁预制件高空坠落受损有限元分析研究

桥梁施工建设当中桥梁预制件高空坠落事故时有发生。由于我国对高空坠落后的桥梁预制件处理方式一般是强制性报废 ,因而造成桥梁施工建设工期的延误。本文分析了损伤的高空坠件的修复及重新利用的可能性 ,并从桥梁施工建设现场取得相关数据 ,利用有限元方法对桥梁预制件高空坠落进行仿真模拟试验 ,根据研究结果进一步提出修缮的方法 ,从而重新利用高空坠件减少建设工期延误。

高速公路半刚性护栏端头研究

从高速公路交通事故的统计资料出发,分析了汽车与高速公路护栏端头碰撞事故原因,利用有限元方法对半刚性波形护栏端头进行仿真模拟试验,根据研究结果进一步提出护栏端头的方法,从而降低事故对乘员的损伤程度。

A simplified simulation method of friction pendulum bearings

In order to improve the computation efficiency and simulation accuracy,a novel simplified simulation method for friction pendulum bearing( FPB) is proposed. The behavior of FPB was analyzed based on the stress characteristics of the slider of FPB. Then,a novel simplified FPB model with a single pendulum and a nonlinear spring was established. The mechanical behavior of the simplified model was analyzed and it conformed well to the basic requirements of FPB. Furthermore,shaking table tests of a concrete slab block structure isolated by four FPBs were carried out, followed by finite element simulations of the test using the proposed simplified model.Three waves and eleven loading scenarios were selected in the test. The results show that the overall trend of the relative displacement time-history curves,the horizontal acceleration time-history curves and the vertical acceleration time-history curves from the numerical simulation match in a good manner with those obtained from the tests. Specifically,it is found that the difference of the peak value within these curves between the simulation and test results is less than 15%,which means that the proposed simplified model can be used to simulate the FPB behaviors under dynamic loadings with acceptable accuracy for engineering purposes.

FEM simulation and experimental verification of roll forming and springback process under complex contact conditions

The application of advanced high strength steel （AHSS） has an important significance in the development of the lightweight of automobile, but the parts made of AHSS usually have defects, such as fracture and large amount of springback, etc. In this paper, a model of multi-pass roll form- ing and springback process of AHSS is established with finite element software ABAQUS. Then a roll forming experiment is performed, and simulation and experimental results have been compared and analyzed. The model is established under complex contact conditions, including self-contact condi- tion. The results shows that during the process of sheet bending, large Mises stresses appear at ben- ding corners. The smaller the bending radius is, the larger the Mises stress and strain are. Thick- ness of sheet metal changes exceeds a certain limit, the differently if the bending radius is different. When the bending radius change tendency of the sheet thickness turns from increase to decrease.

Plastic characterization of metals by combining nanoindentation test and finite element simulation

Materials with the same elastic modulus E and representative stress and strain （σr,εr） present similar indentation-loading curves, whatever the value of strain hardening exponent n. Based on this definition, a good approach was proposed to extract the plastic properties or constitutive equations of metals from nanoindentation test combining finite element simulation. Firstly, without consideration of strain hardening, the representative stress was determined by varying assumed representative stress over a wide range until a good agreement was reached between the computed and experimental loading curves. Similarly, the corresponding representative strain was determined with different hypothetical values of strain hardening exponent in the range of 0-0.6. Through modulating assumed strain hardening exponent values to make the computed unloading curve coincide with that of the experiment, the real strain hardening exponent was acquired. Once the strain hardening exponent was determined, the initial yield stress ay of metals could be obtained by the power law constitution. The validity of the proposed methodology was verified by three real metals： AISI 304 steel, Fe andA1 alloy.

碰撞后快速脱离的新型指示牌立柱设计探讨

汽车与公路指示牌立柱的碰撞是极其危险的交通事故。本文分析了汽车与公路指示牌立柱碰撞事故中车辆受损的原因,提出了碰撞后快速脱离的新型指示牌立柱,并利用有限元方法对汽车碰撞指示牌立柱进行仿真模拟试验,根据研究结果证明结构合理正确,能够在碰撞中减少车辆和乘员的的损伤程度。

汽车与高速公路指示牌碰撞研究

汽车与高速公路指示牌的碰撞是极其危险的事故。本文从高速公路交通事故的统计资料出发,分析了汽车与高速公路指示牌碰撞事故原因,利用有限元方法对汽车碰撞半刚性护栏与指示牌进行仿真模拟试验,根据研究结果进一步提出改进设计的方法,从而降低事故对车内乘员的伤害程度。

航空碳纤维增强树脂基复合材料结构雷击损伤的研究进展

新型飞机均大量使用碳纤维增强树脂基复合材料（CFRP）作为结构用材，若缺乏足够的保护措施，这些CFRP结构在雷击之后往往会出现比传统飞机相应金属结构更为显著的损伤和破坏，因此飞机CFRP结构的雷击防护是一个对航空运行安全具有重大影响的关键问题。本文从人工雷击试验、雷击有限元数值模拟、雷击损伤表征和雷击防护措施四个方面综述了国内外关于雷击对飞机CFRP结构造成的损伤问题的研究进展，为后续开展雷击损伤检测研究奠定基础。