基于Morph功能的改款车模态刚度分析     

温立志  魏健  郑明锋 《天津工程师范学院学报》2013,23(2):13-15

基于ANSA中的Morph功能,在某改款车型的概念设计阶段,对标杆车的有限元模型进行快速的结构调整,通过仿真手段,对改款车的模态刚度进行分析;然后,对原型车白车身结构进行模态实验,获取其模态频率及对应振型,进而与改款车进行对比,提前对改款车结构的合理性做出评价。  相似文献   

The role of shoe design on the prediction of free torque at the shoe–surface interface using pressure insole technology     

Brian Thomas Weaver  Kathleen Fitzsimons  Jerrod Braman 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):370-384

The goal of the current study was to expand on previous work to validate the use of pressure insole technology in conjunction with linear regression models to predict the free torque at the shoe–surface interface that is generated while wearing different athletic shoes. Three distinctly different shoe designs were utilised. The stiffness of each shoe was determined with a material’s testing machine. Six participants wore each shoe that was fitted with an insole pressure measurement device and performed rotation trials on an embedded force plate. A pressure sensor mask was constructed from those sensors having a high linear correlation with free torque values. Linear regression models were developed to predict free torques from these pressure sensor data. The models were able to accurately predict their own free torque well (RMS error 3.72 ± 0.74 Nm), but not that of the other shoes (RMS error 10.43 ± 3.79 Nm). Models performing self-prediction were also able to measure differences in shoe stiffness. The results of the current study showed the need for participant–shoe specific linear regression models to insure high prediction accuracy of free torques from pressure sensor data during isolated internal and external rotations of the body with respect to a planted foot.  相似文献   

滑动运动副接触刚度控制研究     

张丽  孙宝元 《大连大学学报》2002,23(2):48-50

设计并制造了基于NiTi形状记忆合金驱动的间隙可调整（或接触刚度可控）运动副．实验结果表明：这种运动幅间隙可控性好，其接触动刚度变化范围大（最大动刚度是原始动刚度的11倍），具有理想的自适应抗振特性．  相似文献   

获取＂动力硬化＂的一般程式     

张大钧  张海根  刘又午 《天津大学学报(英文版)》1995,(1)

阐述一种获取＂动力硬化＂的一般程式。基于凯恩方程导出做大范围运动任意柔体的运动方程。用几何非线性应变一位移关系和角速度的非线性表达式正确实现线性化，一般情况下可自然获取＂动力硬化＂项。休斯敦方法中偏速度和偏角速度阵列的概念和推导拓宽到柔体，并做为分析的基础。通过用于梁和板模型数值计算的结果证实了所述程式是普遍有效的。  相似文献   

基于Plaxis 2D的基坑支护中内支撑对支护桩的影响分析     

许芸芸  孙忠强 《唐山学院学报》2010,(3):22-24

借助Plaxis 2D的有限元分析程序,计算不同支撑刚度下的支护桩变形及内力,揭示了支护桩支撑轴力与支撑刚度之间的变化规律,分析了两者比值对支护桩的影响曲线,并得出近似比值,用以指导工程实际。  相似文献   

直齿锥齿轮刚度在ANSYS中的有限元分析     

王龙宝 《安徽职业技术学院学报》2012,(4):1-3

运用ANSYS软件对直齿锥齿轮刚度进行有限元分析,确定了直齿锥齿轮刚度的影响因素及规律性,同时将其有限元计算值与其理论计算值进行比较。结果表明:直齿锥齿轮刚度理论计算值与理论计算值偏差随着锥角的增大而增大。  相似文献   

The performance of the ice hockey slap and wrist shots: the effects of stick construction and player skill   总被引：1，自引：0，他引：1  

T.?-C.?Wu  D.?PearsallEmail author  A.?Hodges  R.?Turcotte  R.?Lefebvre  D.?Montgomery  H.?Bateni 《Sports Engineering》2003,6(1):31-39

The purpose of this study was to examine the interaction of players’ skill level, body strength, and sticks of various construction and stiffness on the performance of the slap and wrist shots in ice hockey. Twenty male and twenty female subjects were tested. Ten of each gender group were considered skilled and ten unskilled. In addition to general strength tests, each subject performed the slap and wrist shots with three stick shafts of different construction and stiffness. Shot mechanics were evaluated by simultaneously recording ground reaction forces from a force plate, stick movement and bending from high speed filming and peak puck velocity from a radar gun. Data were analysed with a 4-way repeated measures ANOVA for several dependent variables including peak puck velocity, peak Z (vertical) force, peak bending and stick to ground angles, peak angular deflection of the shaft, and hand placement on the stick. The results indicated that: 1) the slap shot was much faster than the wrist shot corresponding to greater vertical loading force, stick bending, and greater width of the hand placement; 2) the puck velocity was influenced by skill level and body strength but not stick type; and, 3) that skilled players were able to generate more vertical force and bend of the stick, in part, by adjusting their hand positions on the stick. Further studies are needed to address the specific influence of body strength and skill on the techniques of these shots and in relation to stick material and construction properties.  相似文献   

不同速度正向单摇双脚跳绳支撑期下肢及 下肢各关节运动生物力学特征分析          下载免费PDF全文

井兰香 《河北体育学院学报》2019,33(5):83-89

目的：测试不同速度正向单摇双脚跳绳运动支撑期动力学及运动学参数,分析下肢及下肢各关节生物力学特征变化规律。方法：选取12名男性专业跳绳运动员分别完成慢、中、快三种速度正向单摇双脚连续跳绳运动,同步采集跳绳过程地面反作用力和运动学数据,计算支撑期下肢及下肢各关节动力学参数。结果：中速跳绳峰值地面反作用力、爆发力等明显大于慢、快速跳绳（P＜005）,随着跳绳速度升高关节活动范围明显减小（P＜005）,快速跳绳时腿刚度（P＜001）和髋、膝、踝关节刚度值最大（P＜001）,踝关节能量吸收贡献度%最大（P＜001）。结论：慢速、中速双脚连续跳绳可锻炼髋、膝、踝关节周围肌肉的超等长收缩能力,快速跳绳主要锻炼踝关节快速超等长收缩能力及髋、膝关节稳定性;跳绳锻炼时应注意下肢尤其是踝关节拉伸热身,提高柔韧性以降低损伤风险。  相似文献   

Evaluation of a static stretching intervention on vascular endothelial function and arterial stiffness     

Hiromi Shinno  Satoshi Kurose  Yutaka Yamanaka  Kyoko Higurashi  Yaeko Fukushima  Hiromi Tsutsumi 《European Journal of Sport Science》2017,17(5):586-592

Purpose: Maintenance and enhancement of vascular endothelial function contribute to the prevention of cardiovascular disease and prolong a healthy life expectancy. Given the reversible nature of vascular endothelial function, interventions to improve this function might prevent arteriosclerosis. Accordingly, we studied the effects of a 6-month static stretching intervention on vascular endothelial function (reactive hyperaemia peripheral arterial tonometry index: RH-PAT index) and arterial stiffness (brachial-ankle pulse wave velocity: baPWV) and investigated the reversibility of these effects after a 6-month detraining period following intervention completion. Methods: The study evaluated 22 healthy, non-smoking, premenopausal women aged ≥40 years. Subjects were randomly assigned to the full-intervention (n?=?11; mean age: 48.6?±?2.8 years) or a half-intervention that included a control period (n?=?11; mean age: 46.9?±?3.6 years). Results: Body flexibility and vascular endothelial function improved significantly after 3 months of static stretching. In addition to these improvements, arterial stiffness improved significantly after a 6-month intervention. However, after a 6-month detraining period, vascular endothelial function, flexibility, and arterial stiffness all returned to preintervention conditions, demonstrating the reversibility of the obtained effects. Conclusion: A 3-month static stretching intervention was found to improve vascular endothelial function, and an additional 3-month intervention also improved arterial stiffness. However, these effects were reversed by detraining.  相似文献   

The fatigue effect of a simulated futsal match protocol on sprint performance and kinematics of the lower limbs     

Juliano Dal Pupo  Daniele Detanico  Jonathan Ache-Dias  Saray Giovana dos Santos 《Journal of sports sciences》2017,35(1):81-88

This study aimed to investigate the fatigue effects induced by a futsal-specific protocol (FIRP) on sprint performance and the kinematics of the lower limbs. Twenty-one futsal players participated in this study and performed a protocol to simulate the futsal demands. At pre-protocol, half-time and post-protocol, the athletes performed 10-m sprints that were recorded for kinematic analysis. Continuous relative phase (CRP) was calculated to assess the inter-segmental coordination. In addition, vertical (K_VERT) and leg (K_LEG) stiffness were calculated. Analysis of variance (ANOVA) for repeated measures was used (P < 0.05). The main results showed that sprint time increased (P < 0.01) post-protocol when compared to pre- and half-time conditions. Lower values of the step rate (P = 0.01) and higher values of the leg angular velocity (P = 0.02) were verified at the end of the FIRP. The CRP of thigh–leg and leg–foot and the stiffness did not change over the protocol. In addition, the high correlation of CRP between the conditions revealed no changes in coordination pattern. We concluded that futsal related-fatigue induced a decrement on sprint time, changing the kinematics of the lower limbs (decreasing step rate and increasing leg angular velocity). However, neither stiffness nor intersegment coordination during sprints was affected by fatigue.  相似文献