共查询到20条相似文献，搜索用时 125 毫秒
1.
介绍了多柔体系统动力学FMD(FlexibleMultibodyDynamics)的力学模型建立、数值求解和计算机仿真的方法 利用Lagrange方法建立多柔体动力学模型,利用参考文献[10]中的实例进行多柔体假设,将计算机仿真结果进行了比较 相似文献
2.
为获得虚拟场景中车辆真实物理运动和交互性,提出一种基于开放式动力学引擎(ODE)的虚拟仿真平台集成方案.构建具有四自由度的汽车刚体动力学简化模型,分析其ODE特性及刚体连接机理,对车身和车轮之间的悬架系统进行分析,采用ODE中Hinge2进行模拟,分析其刚体动力学方程;基于Quest3D和VS2005进行刚体碰撞检测算法研究,构建一个能实现车辆刚体运动和碰撞检测的虚拟仿真平台,实时对车辆刚体动力学相关参数进行输出.经验证,该虚拟仿真系统具有良好的沉浸感、交互性和实用性. 相似文献
3.
陈立群 《商丘师范学院学报》2000,16(4):120-121
科技史上不乏这样的例子 ,几乎山穷水尽的领域忽然峰回路转 ,犹如老态龙钟的古树长出新枝 ,令人耳目一新 .多体系统动力学便是如此 .多体系统动力学经历了漫长而曲折的发展过程 ,由刚体动力学发展为多刚体系统动力学 ,最终成为多体系统动力学 .即使不包括刚体平面运动和定轴转动这些较为简单的情形 ,由Ｅｕｌｅｒ和Ｌａｇｒａｎｇｅ等奠定基础的经典刚体动力学已有 2 0 0多年历史 .进入 2 0世纪 ,除陀螺力学有较大进展并有效地应用于工程技术外 ,从基本理论角度看 ,刚体动力学几乎陷入“山重水复疑无路”的境地 .然而 ,进入 2 0世纪 6 0年代… 相似文献
4.
蔡建乐 《湖南城市学院学报》1994,(6)
本文简述多刚体系统动力学的建模方式，利用D’Alembert原理导出多刚体系统动力学普遍方程，并综述Roberson—Wittenburg方法，利用图论中某些概念描述多刚体系统的结构特征，引进关联矩阵和通路矩阵，导出树形系统动力学方程的一般形式。 相似文献
5.
本文对固结在转动刚体上柔性梁的动力学问题进行了研究。采用拉格朗日方程建立了转动刚体上柔性悬臂梁系统的动力学方程。并给出刚柔耦合情形下且受外力作用时的系统响应。最后通过仿真计算给出了冲击波对梁的横向变形的影响。 相似文献
6.
研究非完整相对运动动力学系统的Lagrange对称性,给出非完整相对运动动力学系统的Lagrange对称性的定义和判据,并得到非完整相对运动动力学系统的Lagrange对称性导致守恒量的条件和形式。通过算例说明结果的应用。 相似文献
7.
利用多刚体动力学方法建立了基于ADAMS软件平台的往复压缩机曲柄连杆机构动力学仿真分析模型.根据所建立的模型,对压缩机曲柄连杆机构的运动学、动力学特性进行了仿真.通过仿真计算,获得了压缩机各运动件(曲轴、活塞、连杆等)的运动学和动力学参数.根据仿真结果,确定了曲轴的3种特殊工况. 相似文献
8.
秦瑞瑞 《实验室研究与探索》2012,31(6):225-228
针对人体行走的特点,采用多刚体动力学模型。首先把人体骨架简化为16个刚体;然后通过刚体变分运动方程,构造系统的广义坐标矢量、质量矩阵及广义力矢量;接着对正向动力学分析、逆向动力学分析与静平衡分析,求出外力约束条件结果;最后建立虚拟人体运动控制模型。实验仿真给出步行肌肉力矩、连续帧以及单步行结果,其中踝关节前侧肌肉收缩,可产生较大的后蹬力,上行状态步速降低,躯干角度变化明显,单帧连接点转动的角度大。 相似文献
9.
“理论力学”是力学、机械、航空航天等工科专业的核心必修课之一。然而,目前该课程的教学实验大多是原理演示或简单参数测量,不利于学生深刻理解专业知识、提升解决实际问题的综合创新能力。为解决上述难题,围绕人体运动这一典型的多刚体系统动力学问题,构建了基于假人仿真模型的自由式滑雪空中技巧运动生物力学教学实验,涵盖力学模型简化、拉格朗日方程构建、刚体惯性参数计算、动力学仿真软件应用等主要知识点和技能。该教学实验转化自“科技冬奥”重点研发计划的科研成果,具有前沿性、交叉性和综合探究性,有助于提升复合型拔尖跨学科人才的综合实践能力。 相似文献
10.
11.
朱雄军 《武汉职业技术学院学报》2005,4(1):60-62
本文概述了人体Hanavan模型，运用面向对象的技术设计了骨骼类和关节类，实现了多刚体三维人体模型的构建，为模拟三维人体运动打下了基础。 相似文献
12.
王战平 《宁夏师范学院学报》2008,29(3):74-79
本文研究了一类随机非线性时滞种群发展系统,对随机非线性时滞种群发展系统的均方稳定和指数稳定进行了讨论.利用Burkholder-Davis-Gundy不等式,Gronwall引理和Kolmogorov不等式得到了均方稳定和指数稳定的充分条件. 相似文献
13.
In this article we describe a longitudinal study with secondary school pupils which focuses on the relationship between pupils’ cognitive development and understanding dynamics. Two classes of pupils the first between 12–14 and the second between 14 and 16, together with a sub-sample from each of these classes were followed for three years. The main sample completed two tests composed of standard dynamics items and a Piagetian cognitive task. The subsample were interviewed on some of the dynamics items tested and carried out additional cognitive tasks. The results showed that the majority of younger pupils, and the sub-sample reflect the tendency, make very little or no cognitive progress during the three years whereas the older pupils of the main sample and sub-sample make reasonable propgress mainly in the fourth year. The study showed that the relationship between cognitive scores and results on dynamics items is variable with both samples and sub-samples. Further different domains within dynamics related in different ways to cognitive development. An analysis of dynamics concepts suggested that some are more accessible to pupils than others. Three different types of relations are proposed between pupils’ understanding of dynamics concepts and the use of these in the real world. 相似文献
14.
程新英 《石家庄法商职业学院教学与研究》2007,(3)
毛泽东发展观中包括着目标论、价值论、动力论三个主要方面。其目标论中的民族的、民主的、社会主义的等多重含义;其价值论中的以群体与个体相统一的群体主体、以生存关怀与发展关怀相统一的理想实现方式;其动力论中的革命与建设的独特结合都体现了毛泽东发展观的中国特色。 相似文献
15.
The effects of journal misalignment on the transient flow of a finite grooved journal bearing are presented in this study.
A new 3D computational fluid dynamics (CFD) analysis method is applied. Also, the quasi-coupling calculation of transient
fluid dynamics of oil film in journal bearing and rotor dynamics is considered in the analysis. Based on the structured mesh,
a new approach for mesh movement is proposed to update the mesh volume when the journal moves during the fluid dynamics simulation
of an oil film. Existing dynamic mesh models provided by FLUENT are not suitable for the transient oil flow in journal bearings.
The movement of the journal is obtained by solving the moving equations of the rotor-bearing system with the calculated film
pressure as the boundary condition of the load. The data exchange between fluid dynamics and rotor dynamics is realized by
data files. Results obtained from the CFD model were consistent with previous experimental results on misaligned journal bearings.
Film pressure, oil film force, friction torque, misalignment moment and attitude angle were calculated and compared for misaligned
and aligned journal bearings. The results indicate that bearing performances are greatly affected by misalignment which is
caused by unbalanced excitation, and the CFD method based on the fluid-structure interaction (FSI) technique can effectively
predict the transient flow field of a misaligned journal bearing in a rotor-bearing system. 相似文献
16.
Ning Fang 《Journal of Science Education and Technology》2012,21(5):571-580
A concept pair is a pair of concepts that are fundamentally different but closely related. To develop a solid conceptual understanding in dynamics (a foundational engineering science course) and physics, students must understand the fundamental difference and relationship between two concepts that are included in each concept pair. However, all existing research in dynamics and physics education has been focused on the identification and repair of students?? misunderstanding of individual concepts, but not concept pairs. The present research fills the gap of existing research by studying students?? perceptions of dynamics concept pairs and correlation with their problem-solving performance in both particle and rigid-body dynamics. A total of 88 engineering undergraduate students participated in the present study. Students?? perceptions were assessed using a 40-item instrument that included 20 dynamics concept pairs at fundamental Level One and higher-order Level Two. Students?? problem-solving performance was assessed using four exams that included 66 dynamics problems. The coefficients of reliability (Cronbach??s ??) of assessment instruments vary between 0.69 and 0.93. The research findings from the present study show that students were not confident in their understanding of Level-Two concept pairs, especially the relationship between the Principle of Linear Impulse and Momentum and the Principle of Angular Impulse and Momentum, and the relationship between the Principle of Angular Impulse and Momentum and the Conservation of Angular Momentum. A statistically significant correlation exists between students?? perceptions of Level-Two concept pairs and their problem-solving performance on both particle dynamics (r?=?0.355, p?<?0.01) and rigid-body dynamics (r?=?0.351, p?<?0.01). The research findings made from the present study imply that educational efforts should be focused on improving students?? understanding of Level-Two dynamics concept pairs. 相似文献
17.
共享知识作为语境的一部分,在话语理解中起着非常重要的作用。Sperber&Wilson的关联理论中谈到语境作用越强,关联性越大,说话人与受话人的话语活动更易于成功。同时,根据语境的动态性,共享知识也是处于动态之中,并不是固定的,而是随着话语的发展而不断丰富发展的,反之,共享知识的发展又推动了整个话语向前发展。本文主要结合关联理论来论述共享知识在话语理解过程中的作用及其动态性。 相似文献
18.
本文研究了一类随机非线性时变种群发展系统,对随机非线性时变种群发展系统的均方稳定和指数稳定进行了讨论.利用Burkholder-Davis-Gundy不等式,Gronwall引理和Kolmogorov不等式得到了均方稳定和指数稳定的充分条件. 相似文献
19.
浅议当前社会分化的基本动力——以卡尔·波兰尼"嵌入"理论为视角 总被引：1，自引：0，他引：1
魏晨 《湖北广播电视大学学报》2007,27(8):105-106
当前中国社会分化的动力呈现出三种不同经济形态各自作用又相互影响的特点,这种机制导致了社会分化的动力同社会转型的动力缠绕在一起,国家在处理社会分化问题上面临着两难选择。 相似文献