scholarly journals Vertical Stiffness, Jumps and Sprint Kinematics of Well-Trained Youth Female and Male Sprinters

2018 ◽  
Vol 14 (2) ◽  
pp. 1-14
Author(s):  
K. MATTES ◽  
◽  
S. MANZER ◽  
V. RITTHALLER ◽  
M. REISCHMANN ◽  
...  
Keyword(s):  
Vertical Stiffness

Impact of Vertical Stiffness Gradient on the Maximum Divergence Angle

2020 ◽  
Author(s):  
Charles Farbos de Luzan ◽  
Alexandra Maddox ◽  
Liran Oren ◽  
Ephraim Gutmark ◽  
Rebecca J. Howell ◽  
...  
Keyword(s):  
Divergence Angle ◽  
Vertical Stiffness

scholarly journals Gender Difference in Architectural and Mechanical Properties of Medial Gastrocnemius–Achilles Tendon Unit In Vivo

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 569
Author(s):  
Liqin Deng ◽  
Xini Zhang ◽  
Songlin Xiao ◽  
Baofeng Wang ◽  
Weijie Fu
Keyword(s):  
Mechanical Properties ◽  
Gender Differences ◽  
Gender Difference ◽  
Achilles Tendon ◽  
Medial Gastrocnemius ◽  
Regular Exercise ◽  
Training Experience ◽  
Exercise Habits ◽  
Vertical Stiffness

This study aims to explore whether gender differences exist in the architectural and mechanical properties of the medial gastrocnemius–Achilles tendon unit (gMTU) in vivo. Thirty-six healthy male and female adults without training experience and regular exercise habits were recruited. The architectural and mechanical properties of the gMTU were measured via an ultrasonography system and MyotonPRO, respectively. Independent t-tests were utilized to quantify the gender difference in the architectural and mechanical properties of the gMTU. In terms of architectural properties, the medial gastrocnemius (MG)’s pennation angle and thickness were greater in males than in females, whereas no substantial gender difference was observed in the MG’s fascicle length; the males possessed Achilles tendons (ATs) with a longer length and a greater cross-sectional area than females. In terms of mechanical properties, the MG’s vertical stiffness was lower and the MG’s logarithmic decrement was greater in females than in males. Both genders had no remarkable difference in the AT’s vertical stiffness and logarithmic decrement. Gender differences of individuals without training experience and regular exercise habits exist in the architectural and mechanical properties of the gMTU in vivo. The MG’s force-producing capacities, ankle torque, mechanical efficiency and peak power were higher in males than in females. The load-resisting capacities of AT were greater and the MG strain was lesser in males than in females. These findings suggest that males have better physical fitness, speed and performance in power-based sports events than females from the perspective of morphology and biomechanics.

Experimental Study on the Dynamic Deformation of Simply Supported Beam in Chinese High-speed Railway

2018 ◽  
Author(s):  
Gonglian Dai ◽  
Meng Wang ◽  
Tianliang Zhao ◽  
Wenshuo Liu
Keyword(s):  
High Speed ◽  
Structure Design ◽  
Dynamic Coefficient ◽  
Bridge Structure ◽  
High Speed Railway ◽  
Simply Supported Beam ◽  
Vertical Stiffness ◽  
Simply Supported ◽  
Speed Up ◽  
Design Speed

<p>At present, Chinese high-speed railway operating mileage has exceeded 20 thousand km, and the proportion of the bridge is nearly 50%. Moreover, high-speed railway design speed is constantly improving. Therefore, controlling the deformation of the bridge structure strictly is particularly important to train speed-up as well as to ensure the smoothness of the line. This paper, based on the field test, shows the vertical and transverse absolute displacements of bridge structure by field collection. What’s more, resonance speed and dynamic coefficient of bridge were studied. The results show that: the horizontal and vertical stiffness of the bridge can meet the requirements of <b>Chinese “high-speed railway design specification” (HRDS)</b>, and the structure design can be optimized. However, the dynamic coefficient may be greater than the specification suggested value. And the simply supported beam with CRTSII ballastless track has second-order vertical resonance velocity 306km/h and third-order transverse resonance velocity 312km/h by test results, which are all coincide with the theoretical resonance velocity.</p>

scholarly journals Analysis of Vertical Stiffness of Air Spring Based on Finite Element Method

2018 ◽  
Vol 153 ◽  
pp. 06006
Author(s):  
Jiatong Ye ◽  
Hua Huang ◽  
Chenchen He ◽  
Guangyuan Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Element Model ◽  
Simulation Method ◽  
Bench Test ◽  
Air Spring ◽  
Vertical Stiffness ◽  
Element Simulation ◽  
Element Method

In this paper, a finite element model of membrane air spring in the vehicle is established, and its vertical stiffness characteristics under a certain inflation pressure are analysed. The result of finite element simulation method is compared with the result of the air spring bench test. The accuracy and reliability of the finite element simulation method in nonlinear analysis of air spring system are verified. In addition, according to the finite element method, the influence of the installation of the air spring limit sleeve on its stiffness is verified.

scholarly journals Acute Effects of Stretching on Leg and Vertical Stiffness During Treadmill Running

2017 ◽  
Vol 31 (12) ◽  
pp. 3417-3424 ◽  
Author(s):  
Panagiotis T. Pappas ◽  
Giorgos P. Paradisis ◽  
Timothy A. Exell ◽  
Athanasia S. Smirniotou ◽  
Charilaos K. Tsolakis ◽  
...  
Keyword(s):  
Treadmill Running ◽  
Acute Effects ◽  
Vertical Stiffness

The Dynamic Characteristics of Rigid Frame Single-Rib Arch Bridge

2013 ◽  
Vol 368-370 ◽  
pp. 1426-1430
Author(s):  
Li Xiong Gu ◽  
Rong Hui Wang
Keyword(s):  
Dynamic Characteristics ◽  
Bending Strength ◽  
Dynamic Properties ◽  
Structural Parameters ◽  
Bending Stiffness ◽  
Torsional Stiffness ◽  
Lateral Stiffness ◽  
Arch Bridge ◽  
Vertical Stiffness ◽  
Rigid Frame

In this paper, by establishing the finite element model to study the dynamic characteristics of rigid frame single-rib arch bridge. By respectively changing structural parameters of the span ratios, and the compressive stiffness of arch, and the bending stiffness of arch, and the bending stiffness of bridge girder, and the layout of boom to find out the regularity of the structure on lateral stiffness, and vertical stiffness, and torsional stiffness as well as dynamic properties, it come out the results of that lateral stiffness of the structure is weaker, and increasing the span ratios and the compressive strength of arch are conducive to the improvement of the overall stiffness, and improving the bending strength of arch and layout of boom are less effect on the overall stiffness and mode shape.

scholarly journals Mechanical Properties Research on Suspended-dome Structure with Discontinuous Support Under Different Parameters

2017 ◽  
Vol 11 (1) ◽  
pp. 303-314
Author(s):  
Yu Jinghai ◽  
Leng Ming ◽  
Zhang Zhongyu ◽  
Jiang Zhiyu ◽  
Wang Zhengkai
Keyword(s):  
Mechanical Properties ◽  
Parametric Analysis ◽  
Structural Parameters ◽  
Supporting System ◽  
Vertical Stiffness ◽  
Stiffness Constant ◽  
Support Reaction ◽  
Steel Consumption ◽  
Dome Structure ◽  
Scope Of Application

Introduction: For suspended-dome with big partial hole, two kinds of feasible plans were proposed. Method: One of the plans was to adjust suspended-dome’s members, and another to build auxiliary supporting system to support the suspended-dome with columns together. These kinds of suspended-dome’s main structural parameters include stiffness, member force, steel consumption, support reaction and stability, and parametric analysis is based on these parameters. Conclusion: Firstly,the scope of application was illustrated for the former plan. Then, an equivalent vertical stiffness algorithm was put forward for the latter plan. In the latter plan, limit stiffness constant was introduced to quantify the method for solving discontinuous support problem.

Experimental Study on Vertical Base-Isolated System with Disk Spring

2012 ◽  
Vol 166-169 ◽  
pp. 788-792
Author(s):  
Yamin Zhao ◽  
Jingyu Su ◽  
Ming Lu
Keyword(s):  
Shaking Table ◽  
Base System ◽  
Performance Tests ◽  
Shaking Table Tests ◽  
Seismic Responses ◽  
Vertical Stiffness ◽  
Disk Spring ◽  
Fixed Base ◽  
Structural Responses ◽  
Vertical Base

A new vertical isolator designed by disk spring, called combined disk spring bearing (DSB), is introduced in this paper. DSB is composed of one main disk spring bearing and eight secondary disk spring bearings. Performance tests show that DSB had good property of variable vertical stiffness and high vertical damping. Then, the effectiveness of DSB vertical base-isolated devices in reducing structural responses caused by earthquakes through a series of 1/2 scale shaking table tests. are conducted to study the seismic responses of the and the DSB vertical-isolated system. Compared with the fixed-base system, experimental results show that the DSB vertical-isolated system can isolate vertical earthquake energy remarkably. Large displacement of the DSB vertical-isolated system occurred on the isolation layer, and the inter-story deformation of the superstructure changed slightly. The acceleration responses of DSB vertical-isolated system decreased more than 50% and the displacement responses decreased more than 40% at 0.4g PGA, which confirmed that DSB could decrease the seismic responses effectively.

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