SSP定宽机轧制过程的有限元分析

用有限元分析软件ANSYS对SSP定宽机轧制过程进行模拟,分析锤头模块角度,板坯材质,初始宽度对轧制力的影响,以及板材截面的狗骨高度。     

侧压过程板坯温度变化的研究与分析

利用热力耦合有限元的理论,建立了板坯侧压过程的三维热力耦合有限元仿真模型.得到了板坯在稳态变形区内节点温度和轧制力随时间的变化规律,通过轧制力的模拟结果和试验数据比较可知,两者吻合良好.分析结果为板坯侧压规程的制定和轧制力的在线预报提供了理论依据.     

板坯定宽压力机工艺过程模拟

采用DEFORM软件对板坯定宽工艺过程进行成形仿真分析,获得板坯定宽过程的锤头载荷,进而对板坯压力机定宽工艺过程进行动力学仿真。     

表面堆焊制备侧压机模块的性能及应用

采用表面堆焊的方法提高侧压机模块的使用寿命,对侧压机模块堆焊层的力学性能、高温硬度和抗高温氧化性能进行了测试,对堆焊层的显微组织进行了分析,并对侧压机模块进行了现场使用试验.结果表明:表面堆焊提高了侧压机模块的塑性、高温硬度和抗高温氧化能力;堆焊层的显微组织是回火索氏体+少许铁素体;堆焊侧压机模块的使用寿命较国产模块有明显延长,并且可以取代进口模块,降低生产成本.     

1580大侧压定宽机运动学仿真及优化分析

采用n维约束复合形法优化理论,系统地模拟分析了SP轧机同步机构和侧压机构的运动规律。对同步框架大小偏心的尺寸进行优化,计算出同步机构的最大匀速段区间,在此基础上对侧压框架的初始角度和偏心距进行优化分析,得出模块最大有效行程的一组最优值。对SP机构模块运动的实际使用值和优化值进行了比较,为掌握SP轧机的运动特性和进一步改进SP轧机提供了理论依据。     

基于ANSYS Workbench的典型钣金件橡皮囊成形起皱仿真分析

针对航空凸翻边钣金件橡皮囊成形的起皱问题,利用ANSYS Workbench软件对典型钣金件的橡皮囊成形进行有限元仿真分析。找出凸翻边钣金件橡皮囊成形过程中的起皱原因。采取增加侧压块的方法,设计并建立侧压块模型,基于ANSYS Workbench建立橡皮囊成形有限元模型并分别对有无侧压块的橡皮囊成形过程进行仿真模拟。综合仿真与试验的结果,验证了侧压块对起皱控制的有效性以及有限元模型的正确性,为侧压块在钣金件成形中的应用提供可行的理论指导。     

异形坯经压弧制成平面板坯的模拟研究

用有限元软件DEFORM-3D研究将异形板坯通过压弧方法制成平面板坯的过程,同时进行实物的物理模拟试验,再将模拟结果与试验后得到的板坯试样的平面形状进行对比分析,对比结果验证了有限元模拟方法的可行性和正确性。     

凸翻边零件的液压橡皮成形有限元模拟与分析

利用有限元技术,对凸翻边钣金零件的高压橡皮成形过程进行模拟分析.通过增加侧压块和加大毛坯的方式,由数值模拟与分析,指出了侧压块有利于凸翻边件的成形,以及摩擦因素和模具与侧压块之间的距离对凸翻边件成形的影响,为有限元在橡皮成形工艺中的应用积累了参考数据,为其工艺设计提供了参考依据.     

宽厚板轧制过程有限元模拟分析

以大型ANSYS软件中的LS-DYNA模块为平台,对鞍钢5500mm轧机轧辊和板带进行建模。通过设置板带的咬入速度、轧辊的角速度、压下量等初始条件,动态模拟四组不同板宽的单道次轧制过程和施加三组不同压下量的单道次轧制过程,进而分析宽厚板轧制过程中的应力、应变以及板带轧后凸度的变化情况。最后,把模拟结果与现场板带轧制实际数据进行比较,验证分析结果的准确性。分析结果对提高宽厚板产品的质量和精度都具有重要的理论意义和应用价值。     

橡皮成形的有限元模拟

应用非线性有限元分析软件MSC.Marc对侧压块凸弯边橡皮成形进行模拟,分析和预示起皱的原因,研究了侧压块对橡皮成形的影响,得出了侧压块设计的一些规律,为凸弯边橡皮成形侧压块的设计提供了有用的参数,同时也表明数值模拟的可行性与科学性。     

The impulsive loading of cantilevers

The results of the dynamic loading of a cantilever by magneto-motive loading, explosive loading and by high bullet speed impact are compared with the predictions of simple theory which assumes that the load is impulsive.     

基于API579—1／ASMEFFS-1的爆炸容器FAD评定方法

提出了爆炸容器FAD全过程评定方法,建立了含穿透裂纹的圆柱形爆炸容器计算模型,分析了其在三角波载荷作用下的动力响应,利用虚裂纹闭合技术计算了应力强度因子的动力响应特性,结果表明：爆炸容器的FAD评定方法可以有效区分冲量相同而峰值不同的冲击载荷的影响,峰值越大,载荷作用时间越短,容器评定结果越危险;采用传统等效静载荷法进行工程设计,具有较大的安全裕度;同时发现,FAD评定能有效地识别尺寸效应的后果,因此该方法对动载荷下的容器评定尤为有效。     

轴向冲击载荷下圆柱壳动力屈曲的计算机仿真

圆柱壳是工程中最常用的结构元件之一,对圆柱壳在各种基本载荷以及在不同类型载荷的联合作用下的屈曲问题研究一直是应用力学界和结构工程界十分关注的课题,与静力屈曲相比,圆柱壳的动力屈曲问题的研究还不尽完善.文章通过有限元软件ANSYS研究圆柱壳轴向冲击下的动力屈曲问题.     

Reliability analysis of the traction unit of a shearer mechanism with response surface method

The paper presents a High order stochastic response surface method (HOSRSM) for reliability and reliability-based sensitivity analyses of transmission mechanism of a shearer in heavy and impulsive environments. Dynamic analysis is affected by several sources of uncertainty, and it is important to quantify their combined effect on performance of the mechanism in order to aid risk assessment, risk mitigation, and decision-making. A dynamic transmission model of the traction unit is established under the condition of low speed and impulsive load. A performance function is proposed to evaluate the system transmission accuracy. The effects of basic variables in HOSRSM are investigated on calculation efficiency and computation cost of system precision reliability. The results indicate that structure parameters of a sun gear are more sensitive than others. The tooth width is a more sensitive geometric parameter than the diameter of the center hole. The targets are proposed to manufacture and inspect the sun gear in traction unit for safety.     

Impact wear of MgO single crystals I. Wear characteristics

The impact wear characteristics of MgO single crystals have been investigated using an impact testing machine provided with a sintered alumina hammer having a tip radius of 2 mm. There is a fixed zero wear duration time for each selected impact load. Plastic deformation caused by slip of the {110} planes and cracking by impact occur during zero wear, but wear fragment are not produced. The zero wear period corresponds to a process of impact fatigue. Measurable wear, which is obtained by repeated impact over the zero wear limit, depends on the impact load and the action of wear fragments. When the test is performed in water wear is accelerated by abrasive erosion caused by impulsive flow of water containing wear fragments between the hammer and the scar wall.     

压电驱动共振式高频疲劳试验机构的设计与实验

针对在小振幅、高频受力工况下微小与硬脆材料构件的疲劳检测,提出利用压电振子(PZT、PLZT或PMN)作为高频疲劳试验机构的驱动力源,并利用系统共振方法设计高频疲劳试验机构.首先,介绍压电共振式疲劳试验机构的工作原理,建立了动力学模型,获得了系统的动态特性.然后,设计和制作了样机.最后,利用样机测量了作用在试件上的动载荷.实验结果表明;改变输入交流电压幅值(100～250 V)和板弹簧厚度(1.1～0.6 mm),可施加在试件上的动载荷为24.7～99.2 N.本文制成的样机适用于测试动载荷在为24.7～99.2 N,且在小振幅、高频受力工况下试件的拉伸和弯曲疲劳性能.     

油膜轴承传动轴系动载系数计算方法

针对传动轴系动载荷变化难以准确用数学函数描述的问题,基于刚体动力学理论,综合考虑轴系刚性与弹性振动特性,提出近似求解动载荷的分析方法,建立轴系动载荷分析模型。通过分析现有油膜轴承试验装置中传动轴系的机械结构组成,推导传动轴系在启制动工况突变时的动载系数计算公式;根据传动轴系的结构参数,确定动载系数取值范围;同时给出该动载系数模型在工程应用中的典型形式。计算表明：轴系在启制动之前,相比没有静压润滑的情况,使用静压润滑的油膜轴承的动载系数相对较小,振动对其油膜稳定性的影响较小。     

Reciprocating impact wear testing apparatus

A reciprocating impact wear testing apparatus has been developed for studies of wear occurring between solid materials undergoing repetitive impulsive loading. Such loading may be purely normal or may include simultaneous transverse sliding. The apparatus is designed to allow measurement of the impact load pulse and to provide for the maintenance of repeatable force pulses for the duration of a prolonged series of impacts (millions of cycles). When utilized with a flat-nosed impacting specimen, the time-invariant impulse waveform results in repeatable surface and subsurface stress cycling of materials undergoing wear. This paper describes the testing apparatus and procedures and includes results from a preliminary series of tests on two polymeric materials.     

An analytical and experimental study of impulsive stress of square plates at an impact loading point by the 3-dimensional dynamic theory of elasticity

In this paper, a new method is proposed to analyze impulsive stresses at an impact loading point, which cannot be solved by the classical plate theory. Particularly, impulsive stresses at an impact loading point under any impact conditions (regardless of mass of impactor, velocity of impactor, stiffness of plate, etc.), can be obtained by the three-dimensional dynamic theory of elasticity and potential theory of displacement. In addition, by using the Hertzian contact theory, impact loading can be analyzed to account for the local deformation, and this load is applied to the impulsive stress analysis by approximating the impact loading to an analyzable function. In the numerical analysis, the Fourier transform (FFT) algorithm and the numerical inverse Laplace transformation are utilized. Using a new equation, it was possible to analyze impulsive stresses at an impact loading point, and good agreement between the experimental and theoretical results was established.     

A self-balancing crane

A simple mechanism is described which has the effect that an automatic displacement of a counterweight very nearly cancels the overturning moment caused by the load. This mechanism is then adapted to a hammerhead crane with movable trolley. An exact static analysis is given, variants are discussed and historical references made.