Objective Rating of the Launch Behavior of Conventional,Hybrid and Electric Vehicles

The calibration of conventional,hybrid and electric drivetrains is an important process during the development phase of any vehicle.Therefore,to optimize the comfort and dynamic behavior(known as driveability),many test drives are performed by experienced drivers during different driving maneuvers,e.g.,launch,re-launch or gear shift.However,the process can be kept more consistent and independent of human-based deviations by using objective ratings.This study first introduces an objective rating system developed for the launch behavior of conventional vehicles with automatic transmission,dual-clutch transmission,and alternative drivetrains.Then,the launch behavior,namely comfort and dynamic quality,is compared between two conventional vehicles,a plug-in hybrid electric vehicle and a battery electric vehicle.Results show the benefits of pure electric drivetrains due to the lack of launch and shifting elements,as well as the usage of a highly dynamic electric motor.While the plug-in hybrid achieves a 10%higher overall rating compared to the baseline conventional vehicle,the pure electric vehicle even achieves a 21%higher overall rating.The results also highlight the optimization potential of battery electric vehicles regarding their comfort and dynamic characteristics.The transitions and the gradient of the acceleration build-up have a major influence on the launch quality.

NONLINEAR DYNAMIC SIMULATION OF AN AXIALLY SLIDE-SPIN ROCKET FLEXIBLE SYSTEM WITH CLEARANCE

A hybrid approach is presented to investigate the dynamic behavior of anaxially slide-spin flexible rocket with nonlinear clearance. The equations of motion of the flexiblerocket are derived based upon Euler-Bernoulli beam theory and Hamilton principle and the finiteelement method. The characteristics of clearance between the spinning rocket and launcher areconsidered to be piecewise linear. Numerical solution is developed by direct integration method anddemonstrates the validity of the method. The coupled dynamic behavior of axial motion and transversevibrations of rocket are analyzed, and the influences of axially moving acceleration, spin speed,linking stiffness of elastic 'shoes', and the nonlinearity of clearance on the motion attitude ofrocket are studied.

弹-架间隙的非线性模拟与特性分析

以大长径比低速旋转火箭为例 ,探讨弹 -架间隙非线性特性对不同发射装置系统的动力响应的影响。当飞行器以 S个定心部沿发射装置滑移时 ,根据弹、架横向相对位移确定其定心部处接触刚度和支承特性 ,模拟弹 -架间隙效应。分别就刚性和柔性两种发射装置 ,分析了间隙量、支承刚度和转速等因素对飞行器发射中的姿态和系统动力特性的影响 ,算例与实际情况的相吻合证明了该方法的有效性。

柔性旋转火箭发射时的弹—管间隙效应

本文研究了弹—管间隙存在的情况下柔性飞行器的发射动力学特性。提出了描述弹—管间隙效应的物理模型 ,根据横向弹、管相对位移确定火箭在发射中的运动和约束状况 ,通过变接触刚度模拟弹—管间的耦合反力和间隙作用 ,数值计算火箭瞬态动力学响应 ,分析了弹—管间隙对火箭运动姿态的影响。

燃气射流对多管火箭炮动态响应的影响分析

燃气射流是影响多管火箭振动、起始扰动和射击密集度的因素之一,分析燃气射流冲击力对多管火箭动态特性的影响为提高多管火箭射击密集度提供思路。应用多体系统传递矩阵法,建立了考虑火箭燃气射流对发射装置冲击效应的多管火箭发射动力学模型,推导了考虑燃气射流冲击力的多管火箭动力响应分析的动力学方程,形成了考虑燃气射流冲击力的多管火箭动力学仿真系统。计算分析了不同火箭燃气射流冲击力下的火箭炮动力响应,火箭弹膛内运动、起始扰动和密集度,表明燃气射流冲击力对火箭炮动力响应、火箭弹起始扰动和密集度有一定的影响,对多管火箭设计具有参考价值。

埋头弹药发射过程药筒力学特性分析

埋头弹药是一种新型战场用弹药,自动机采用旋转闭锁新原理,供弹与退壳同步进行。在发射过程中埋头弹药的工况不同于传统的弹药筒,针对埋头弹药在特殊工作条件下药筒内压变化及变形特征,分析了药筒的动力学过程,获得了药筒在贴壁前、贴壁后、卸载过程的力学特性。通过数值分析发现:在最大膛压为400MPa条件下,聚乙烯药筒性能良好,卸压后能迅速弹性恢复。在此基础上设计了金属与塑料耦联的35mm埋头弹药筒,射击实验表明该药筒满足连发射击要求。

大型旋转飞行器在非线性不对称支承条件下的发射特性分析

以大型、远程旋转火箭为例 ,将飞行器仿真为具有多个非线性、不对称支承的 Euler-Bernoulli旋转梁 ,根据有限元方法和 Hamilton原理建立飞行器的运动控制方程 ,利用分段线性化方法近似弹性支承的非线性刚度 ,数值仿真并分析了推力偏心、质量偏心、结构柔性和支承非线性等因素对飞行器动力响应的影响 ,可望为新一代。

盾构无障碍始发施工力学行为研究

始发洞口处采用玻璃纤维筋代替普通钢筋的混凝土围护结构,无需人工凿除,可实现盾构无障碍始发。通过数值分析进行无障碍始发时桩体背后土体、围护桩体及地表沉降的施工力学行为分析,对比分析数值模拟计算的地表沉降值与采用盾构无障碍始发标段实测结果,证明施工过程整体安全稳定,可推广使用。