瞬态

Incurrent research, aiming at the rupture problem engendered in the shooting process of acertain 5.56mm automatic rifle, the strain and stress distributions on the cartridge caseunder the action of axial pull have been analyzed. Based on the theories of elastic-plasticmechanics and contact mechanics, a mathematic and physical model of the cartridge-caseand chamber system has been set up; and based on the platform of the general softwarepackage APDL of ANSYS for finite element analysis, a parameterized model of thecartridge-case and chamber system has also been established. The method for nonlinearFEA has been adopted to analyze the stress distribution on the entire cartridge-case andchamber system, and the method of contact element has been employed to investigate thecontact stress between the cartridge case and chamber, and then the influences of frictioncoefficient and locking space on the static and dynamic stress and strain response of thecartridge case and chamber to the action of power gas have also been discussed. On thebasis of a lot of numerical tests, a kind of element Plane13, which is concentrated incoupled computation of heat and construction, has been used finally to simulate thetransient response of the cartridge-case and chamber system to the power gas. Throughloading the temporary thermal characteristics of explosive gas in the procedure of emulate, the corresponding transient thermal stress distributed on the entire system under thecombined load of transient thermal stress and transient pressure has been obtained. Owingto these comprehensive considerations, the numerical results obtained in this paperrepresent the actual situations comparatively exactly.

本文针对某5.56mm自动步枪在工作中出现断壳的问题，分析了弹壳在轴向拉力作用下的应力应变；基于弹塑性力学及接触理论，建立了弹壳弹膛系统的数学、物理学模型，在通用有限元ANSYS软件的参数化建模工具APDL平台上，建立了弹壳弹膛系统的参数化模型；采用非线性有限元法计算了弹壳弹膛系统的整体应力，引入接触单元法分析弹壳和弹膛的接触压力，探讨了在不同的摩擦系数和不同的闭锁间隙对弹壳弹膛静、动态响应的影响；本文进行了大量的尝试，最后确定采用热、结构耦合单元Plane13，在计算中加载了火药气体的温度历程，成功的获得了弹壳弹膛系统在瞬态的热载荷和瞬态的压力载荷同时作用下弹壳弹膛系统的热应力数值解，考虑因素全面，比较真实的反映了弹壳弹膛系统在火药气体压力和热载荷下作用的情况。

Then, time-dependent models of the MOCVD reactor can help identify the visual transient behavior inside the reactor and analyze the phenomena of delay time, relaxation oscillation and pulsative oscillation.

在此基础上，计算并可视化了质量输运过程的瞬态行为，分析了延迟时间、驰豫振荡、自脉动振荡等瞬态现象产生的原因，为高品质外延生长工艺的设计提供了有效的解决方案。

Then, time-dependent models of the MOCVD reactor can help identify the visual transient behavior inside the reactor and analyze the phenomena of delay time, relaxation oscillation and pulsative oscillation.

在此基础上，通过微扰反应器的进气量，计算并图形化了质量输运过程的瞬态行为，分析了延迟时间、驰豫振荡、自脉动振荡等瞬态现象产生的原因，为高品质外延生长工艺的设计与实施，提供了有益的解决途径。

Through simulation of the real process of thomcolumbar burst fracture and use of modem dynamics techniques, the present study was (1) to investigate the kinetic relationship between structural damage and impact energy absorption and dynamics mechanism of thoracolumbar burst fracture by quantitative analysis of various injured segments;(2) to explore the instability mechanism of L1 vertebral burst fracture and its injury threshold by three-dimensional analysis of the injured segment with stereophotogrammetry in combination of transient physical parameters, anatomy and image;(3) to explore the corresponding relationships between impact energy, geometry parameters and biomechanics by geometry and biomechanical analysis of thoracolumbar burst fracture, which may provide an objective standard for evaluation of spinal injury severity and experimental evidence for adoption of biomechanical treatment in clinic;(4) to evaluate the fixation effect of different instruments and the effect of intervertebral bone graft on segment fixation by analysis of the threedimensional stability of different internal fixation instruments and their decompression of the spinal canal, which may provide experimental evidence for therapeutical selection for thoracolumbar burst fracture in future; and finally to investigate the effect of various instrument fixation on dynamical characteristics by comparison and quantitative analysis of frequency and amplitude responses, which may provide certain theories and experimental evidence for application of vibration test to judge the stability of the spine.

本研究从胸腰段脊柱爆裂骨折发生的实际过程出发，以现代动力学检测及计算机多通道高性能数据采集分析系统等高新技术为基础，实时量化分析损伤节段的工程参数，揭示了结构破坏与能量吸收的变化规律，探讨了胸腰段脊柱爆裂骨折的瞬态损伤机制；利用三维立体摄像技术，对不同损伤程度的节段进行三维运动分析，结合瞬态物理参数、影像学和病理解剖，明确了〓椎体爆裂骨折的失稳机制及损伤阈值；通过对胸腰椎爆裂骨折的几何学变化及生物力学分析，明确了撞击能量与几何参数、几何参数与生物力学的相应关系，为评判脊柱损伤程度提供了客观标准，为治疗中采取适宜的生物力学方法提供了实验依据；通过对比分析不同内固定器械的三维稳定性和对椎管的减压作用，评价不同器械的复位固定作用，同时比较椎体间植骨对节段固定作用的影响，为今后临床胸腰段脊柱爆裂骨折的治疗选择提供依据；利用振动测试与分析技术，比较及量化分析了不同致伤状况的频幅响应特征，比较分析了各种器械固定对动力学特性的影响，为今后临床建立基于振动测试与分析技术判断脊柱稳定性的诊断方法，提供了一定的理论和实验依据。

By Ensemble-averaged Method, the mean field was got to show the 3D structure of flow. By Phase-locked Averaged Technique, the periodic mean field was got to reflect the periodic unsteady characteristic. The 3D structure and the periodic unsteady characteristic of the unsteady flow within the vaneless and vaned diffuser were discussed through analyzing the mean field and the periodic mean field.

离心风机扩压器内非定常流动的实验研究本文完成了离心风机两种结构条件下无叶扩压器、有叶扩压器内部的非定常流动瞬态全流场的实验测量，获得了不同运行工况下PIV的瞬态流谱，为研究扩压器内部非定常流动提供了基础实验资料。

Based on multi-conductor transmission lines and dipole method, a numerical method to predict the transient electromagnetic environments due to the operation of switches in air-insulated substation is proposed. After a model of busbars in a 500kV substation is set up, the transient electromagnetic field is predicted.

4提出了将多导体传输线时域有限差分法和电偶极子法相结合的空气绝缘变电站瞬态电磁环境数值预测方法，并对一座500kV变电站开关操作产生的瞬态电磁环境进行了预测计算，获得了可用于指导二次设备下放后其电磁屏蔽设计的关键数据。

A transient thermal coupling model of certain internal combustion engine exhaust valve train was built, transient thermal-field distribution of the valve was simulated, and the effect of the thermal conductivity to the thermal-field was discussed.

通过建立某发动机排气门组瞬态热分析藕合模型，对排气门进行瞬态温度场有限元模拟，并探讨导热系数对气门温度场的影响。

Although these parameters can be gained through solving sinusoidal electromagnetic field by FEM, the conversion of end resistance and reactance of damper winding is a tough problem.

当然应用似稳场的有限元分析也是可以确定出这种电机的瞬态和超瞬态电抗以及相应的时间常数。

In accordance with the classic thermal conduction equation and the linear elastic dynamics equation, this paper analyzed the changing of material's optical and thermal physical properties under laser irradiation.

数值结果表明：材料内部的瞬态温度场分布在一个很小的局部区域，该区域存在很大的温度梯度，且分布极不均匀，材料热物理参数随温度的变化对整个瞬态温度场的影响很大。

It obtains the dynamic response results including simulation nephograms of dynamics stress and displacement and curve of dynamic stress of representative nodes.lt analyzes the influences of the braking time to the structure and gains the general methods and steps in solving this kind of problem.

5利用ANSYS8.1对起重机回转制动进行瞬态动力学分析，从而获得臂架系统在该工况时的瞬态动力响应，包括动应力、动位移响应仿真云图和典型节

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。