The Fracture of Two-layer Leaf Spring: Experiments and Simulation

2021 ◽  
pp. 105971
Author(s):  
Guang Cheng ◽  
Kaiyuan Chen ◽  
Yu Zhang ◽  
Yuanchang Chen
Keyword(s):  
Leaf Spring

scholarly journals Study on dynamic characteristics of leaf spring system in vibration screen

2021 ◽  
pp. 146134842110229
Author(s):  
Jiacheng Zhou ◽  
Chao Hu ◽  
Ziqiu Wang ◽  
Zhengfa Ren ◽  
Xiaoyu Wang ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Vertical Direction ◽  
Maximum Amplitude ◽  
Exciting Force ◽  
Mode Shapes ◽  
Leaf Spring ◽  
Amplification Factors ◽  
Simulation And Experiment ◽  
Exciting Forces ◽  
Spring System

By studying dynamic characteristics of the leaf spring system, a new elastic component is designed to reduce the working load and to a certain extent to ensure the linearity as well as increase the amplitude in the vertical and horizontal directions in vibration screen. The modal parameters, amplitudes, and amplification factors of the leaf spring system are studied by simulation and experiment. The modal results show that the leaf spring system vibrates in horizontal and vertical directions in first and second mode shapes, respectively. It is conducive to loosening and moving the particles on the vibration screen. In addition, it is found that the maximum amplitude and amplification factor in the horizontal direction appear at 300 r/min (5 Hz) while those in the vertical direction appear at 480 r/min (8 Hz), which are higher than those in the disc spring system. Moreover, the amplitude of the leaf spring system increases proportionally with the increase of exciting force while the amplification factors are basically the same under different exciting forces, indicating the good linearity of the leaf spring system. Furthermore, the minimum exciting force occurs in the leaf spring system under the same amplitude by comparing the exciting force among different elastic components. The above works can provide guidance for the industrial production in vibration screen.

Modal Strain Energy based Crack Inspection in Mono Composite Leaf Spring

2021 ◽  
Author(s):  
N. I. Jamadar ◽  
S. B. Kivade ◽  
K. K. Dhande ◽  
Khaleefah Manhal ◽  
Rakesh Roshan
Keyword(s):  
Strain Energy ◽  
Leaf Spring ◽  
Modal Strain Energy

scholarly journals Individual stiffness optimization of dorsal leaf spring ankle–foot orthoses in people with calf muscle weakness is superior to standard bodyweight-based recommendations

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Niels F. J. Waterval ◽  
Merel-Anne Brehm ◽  
Jaap Harlaar ◽  
Frans Nollet
Keyword(s):  
Muscle Weakness ◽  
Energy Cost ◽  
Activity Level ◽  
Calf Muscle ◽  
Leaf Spring ◽  
Foot Orthoses ◽  
Ankle Foot Orthoses ◽  
The Individual ◽  
Optimal Stiffness ◽  
Walking Energy Cost

Abstract Background In people with calf muscle weakness, the stiffness of dorsal leaf spring ankle–foot orthoses (DLS-AFO) needs to be individualized to maximize its effect on walking. Orthotic suppliers may recommend a certain stiffness based on body weight and activity level. However, it is unknown whether these recommendations are sufficient to yield the optimal stiffness for the individual. Therefore, we assessed whether the stiffness following the supplier’s recommendation of the Carbon Ankle7 (CA7) dorsal leaf matched the experimentally optimized AFO stiffness. Methods Thirty-four persons with calf muscle weakness were included and provided a new DLS-AFO of which the stiffness could be varied by changing the CA7® (Ottobock, Duderstadt, Germany) dorsal leaf. For five different stiffness levels, including the supplier recommended stiffness, gait biomechanics, walking energy cost and speed were assessed. Based on these measures, the individual experimentally optimal AFO stiffness was selected. Results In only 8 of 34 (23%) participants, the supplier recommended stiffness matched the experimentally optimized AFO stiffness, the latter being on average 1.2 ± 1.3 Nm/degree more flexible. The DLS-AFO with an experimentally optimized stiffness resulted in a significantly lower walking energy cost (− 0.21 ± 0.26 J/kg/m, p < 0.001) and a higher speed (+ 0.02 m/s, p = 0.003). Additionally, a larger ankle range of motion (+ 1.3 ± 0.3 degrees, p < 0.001) and higher ankle power (+ 0.16 ± 0.04 W/kg, p < 0.001) were found with the experimentally optimized stiffness compared to the supplier recommended stiffness. Conclusions In people with calf muscle weakness, current supplier’s recommendations for the CA7 stiffness level result in the provision of DLS-AFOs that are too stiff and only achieve 80% of the reduction in energy cost achieved with an individual optimized stiffness. It is recommended to experimentally optimize the CA7 stiffness in people with calf muscle weakness in order to maximize treatment outcomes. Trial registration Nederlands Trial Register 5170. Registration date: May 7th 2015. http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5170.

Response of Composite Leaf Springs to Low Velocity Impact Loading

2014 ◽  
Vol 591 ◽  
pp. 47-50 ◽  
Author(s):  
S. Rajesh ◽  
G.B. Bhaskar
Keyword(s):  
Impact Test ◽  
Low Velocity Impact ◽  
Leaf Spring ◽  
Fiber Reinforced ◽  
Test Rig ◽  
Low Velocity ◽  
Velocity Impact ◽  
Fiber Reinforced Plastic ◽  
Leaf Springs ◽  
Reinforced Plastic

Leaf springs are the traditional suspension elements, occupying a vital position in the automobile industry. This paper deals us the replacement of existing steel leaf spring by composite leaf spring. The dimensions of existing middle steel leaf spring of commercial vehicle (Tata ace mini truck) were taken and fabricated using a specially designed die. Single leaf of the suspension springs, each made up composite with bidirectional carbon fiber reinforced plastic (CFRP), bidirectional glass fiber reinforced plastic (GFRP) and hybrid glass-carbon fiber reinforced plastic (G-CFRP), was fabricated by hand layup process. It is to be mentioned here that the cross sectional area of the composite spring same as the metallic spring. A low velocity impact test rig was fabricated in the laboratory with loading set up. The composite leaf springs were tested with the low velocity impact test rig. By using the low velocity impact test rig, the deflection due to various drop height were measured.

Vehicle’s New Anti-Roll System for Suspension Parasitic Stiffness Reduction and Non-Linear Roll Stiffness Characteristic

2013 ◽  
Author(s):  
Bo Min Kim ◽  
Dae Sik Ko ◽  
Jong Min Kim
Keyword(s):  
Ride Comfort ◽  
Torsional Stiffness ◽  
Operating Efficiency ◽  
Leaf Spring ◽  
Roll Motion ◽  
Stiffness Reduction ◽  
Stiffness Characteristic ◽  
Non Linear ◽  
Roll System ◽  
Vehicle Dynamic Simulation

In general, vehicle uses torsional stiffness of a stabilizer bar to control the roll motion. But this stabilizer bar system has problems with degradation for ride comfort and vehicle’s NVH characteristic due to the suspension parasitic stiffness caused by deformation and wear of the stabilizer bar rubber bush. In addition, it is difficult to control the vehicle’s roll motion effectively in case of excessive vehicle roll behavior when it is designed to satisfy ride comfort simultaneously because of the stabilizer bar’s linear roll stiffness characteristic. In this paper, the new anti-roll system is suggested which consists of connecting link, push rod, laminated leaf spring, and rotational bearing. This new concept anti-roll system can minimize the suspension parasitic stiffness by using rotational bearing structure and give the vehicle non-linear roll stiffness by using the laminated leaf spring structure which are composed of main spring and auxiliary one. Reduction of suspension parasitic stiffness and realization of non-linear roll stiffness in this anti-roll system were verified with both vehicle dynamic simulation and vehicle test. Also, this study includes improvement of the system operating efficiency through material change and shape optimization of the leaf spring, and optimal configuration of the force transfer system.

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