查询词典 analytic

The basic approach of protecting people from being hurt or killed in an accident is to improve crashworthiness of vehicles. This paper starts with discussing theories and methods for vehicle passive safety design, which included experiential methods, analytic methods, multi-body dynamics methods, crash test methods and the finite element method. Emphasis will be paid to the basic FEM theories and algorithms of impact problems. Topics discussed include the governing equation, element discretization, hourglass control, time integration, material model, shell element algorithms and contact-impact algorithms. For more reliable simulation results, this paper then conducts study on how to accurately get material model parameters by combining the FEM method with experimental method, and develops relevant material test machine and parameter calculating software. Based on that, basic typical impact simulation and test validation study are conducted. On the basis of the above work, the paper studies the thin-shell structures'crashworthiness, which was affected by the following factors: spot-weld features, shell thickness, cross-section and pre-deformation. As to vehicle parts'crashworthiness, the paper conducts simulation study of designing energy-absorbing steering system and adaptive airbag system. A practical energy-absorbing steering wheel is designed as an example. In further depth research, the paper suggests several inverse quantificational methods for vehicle crashworthiness design based on the ideal crash characteristics. The above theories and methods are applied with good results through several practical vehicles' crashworthiness design and improvement.

文中对汽车碰撞安全性的设计理论和方法进行了归类和总结，其中包括经验法、解析法、多刚体动力学法、试验法以及有限元方法等；重点介绍了碰撞有限元法的基本理论和有关算法，涉及到有限元求解控制方程、单元离散、沙漏模态控制、时间积分、材料模型和应力修正、薄壳单元算法以及接触碰撞界面算法等，探讨了有限元计算中的材料模型参数获取技术，开发了相应的材料试验装置及材料模型参数反求软件，在此基础上进行了基本的碰撞仿真算例和试验对比研究；文中通过应用有限元方法研究了薄壁构件的碰撞吸能特性，指出了设计薄壁吸能构件时需要考虑的几个主要影响因素，即焊点、壁厚、横截面和预变形等；在关于车辆部件的碰撞安全性能设计中进行了吸能转向机构和自适应安全气囊的仿真研究，提出了吸能转向机构和自适应安全气囊的仿真研究方法；文中最后探讨了整车碰撞性能的设计与改进方法，提出了以理想碰撞特性为目标，采用分段加速度或者根据碰撞时间进行设计的反推设计法、部件吸能仿真优化设计法等量化设计方法，并通过综合应用文中所讨论的相关技术进行了整车碰撞性能的设计与改进实例研究，所选定的车型是大众化的普通轿车和碰撞安全性基础较差的微型面包车，研究结果表明，本文所提出的设计与改进方法是适用而有效的，具有重要的工程实用意义和价值。

In addition, this paper gives the analytic expression of space posit...

给出了采用关节式测头架的测量机的数学模型

The characteristic equation of the beam is derived, as well as an analytic expression of its eigenfunction.

推导了此梁弯曲振动的频率方程及振型函数的解析表达式。

Besides, the multinomial analytic expression of the intensity is get.

此外，给出了散射光分布的多项式解析表达。

The analytic expression of its stacking line is deduced.

推导了其积迭线的解析表达式。

It is difficult to build an analytic expression that includes all the factors to describe the heat flow in electrical apparatus.

电器各部分的发热与散热是一个非常复杂的过程，影响它的因素很多，很难建立一个考虑到所有影响因素的热过程解析公式。

By using simple model, an analytic expression about the parasitic capacitances' impact on linearity is obtained.

利用一个简单模型，得出了寄生电容对线性度影响的解析表达式。

A function must have the same analytic expression throughout.

一个函数必须处处都有相同的解析表达式。

Based on the original research of the high order single step method ,this paper makes the research on the applicability of this method for the analytic expression of stiffness.

本文在原有高阶单步法研究的基础上对刚度为时间解析函数时方法的适用性进行了研究。

Based on which, a necessary and sufficient condition for the existence of controllers is derived and the analytic expression of expected controllers is proposed.

汽约束下具有鲁棒稳定性的充要条件，在此基础上，得到了Delta算子系统状态反馈控制器存在的充要条件和解析表达式。

Through comparing with the results by simulation to study the effects of theprojectile"s final velocity, the angle of rotation and the ballistic trajectory"s migration withdifferent projectile"s rotating speeds, different target"s moving speeds and differentpenetration angles.

通过比较数值模拟的结果来研究不同弹头转速、目标速度、侵彻角对侵彻过程中弹头最终速度、翻转角度和弹道偏移的影响。

I love stationery and all the accoutrement of writing.

我爱文具以及所有的书写的工具装备。