Wear-Life Analysis and Optimization of a Typical Folding Mechanism

2013 ◽  
Vol 651 ◽  
pp. 678-683
Author(s):  
Juan Zhang ◽  
Zuo Jun Li ◽  
Bin Bai ◽  
Jia Zhou Bian
Keyword(s):  
Reliability Analysis ◽  
Stress Level ◽  
Nonlinear Dynamic ◽  
Maximum Stress ◽  
Folding Mechanism ◽  
Kinematics Simulation ◽  
Wear Life ◽  
Parameterized Modeling ◽  
Lifetime Analysis ◽  
Life Analysis

A method of modeling and kinematics simulating of a typical flexible folding mechanism in multi-software platform was proposed in this paper, which aimed at its complex nonlinear dynamic characters. Based on this method, parameterized modeling and kinematics simulation of a typical folding mechanism was put forward firstly, and then the reliability analysis and wear lifetime analysis of folding mechanism were studied through different reliability analysis methods. Finally, the wear life of such folding mechanism was optimized. The optimization results showed that the Maximum stress level was decreased and the wear life was increased significantly.

Wear-life analysis of deep groove ball bearings based on Archard wear theory

2018 ◽  
Vol 32 (7) ◽  
pp. 3329-3336 ◽  
Author(s):  
Guangwei Yu ◽  
Wei Xia ◽  
Zhuoyuan Song ◽  
Rui Wu ◽  
Siling Wang ◽  
...  
Keyword(s):  
Ball Bearings ◽  
Wear Life ◽  
Deep Groove ◽  
Life Analysis

The Influence of Test Temperature on the Ratchetting Behavior of Type 304 Stainless Steel

1989 ◽  
Vol 111 (4) ◽  
pp. 378-383 ◽  
Author(s):  
M. B. Ruggles ◽  
E. Krempl
Keyword(s):  
Stress Level ◽  
Driving Force ◽  
Room Temperature ◽  
Maximum Stress ◽  
Elevated Temperatures ◽  
304 Stainless Steel ◽  
Short Time ◽  
Independent Behavior ◽  
Type 304 ◽  
Type 304 Stainless Steel

The zero-to-tension ratchetting behavior was investigated under uniaxial loading at room temperature and at 550, 600, and 650°C. In History I the maximum stress level of ratchetting was equal to the stress reached in a tensile test at one percent strain. For History II the maximum stress level was established as the stress reached after a 2100 s relaxation at one percent strain. Significant ratchetting was observed for History I at room temperature but not at the elevated temperatures. The accumulated ratchet strain increases with decreasing stress rate. Independent of the stress rates used insignificant ratchet strain was observed at room temperature for History II. This observation is explained in the context of the viscoplasticity theory based on overstress by the exhaustion of the viscous contribution to the stress during relaxation. The viscous part of the stress is the driving force for the ratchetting in History I. Strain aging is presumably responsible for the lack of short-time inelastic deformation resulting in a nearly rate-independent behavior at the elevated temperatures.

Influence of Internal Stresses on the Stressing of Material in Components Subjected to Rolling-Contact Loads

1984 ◽  
Vol 106 (4) ◽  
pp. 499-504 ◽  
Author(s):  
E. Broszeit ◽  
J. Adelmann ◽  
O. Zwirlein
Keyword(s):  
Half Space ◽  
Stress Level ◽  
Maximum Stress ◽  
Equivalent Stress ◽  
Local Stress ◽  
Rolling Contact ◽  
Internal Stresses ◽  
Contact Loads ◽  
Distortion Energy ◽  
Von Mises

The stressing of a material in concentrated contacts can be calculated using f.e. the equivalent stress hypothesis by Huber, von Mises, Hencky (distortion energy hypothesis). The stress level can be directly related to the local yield properties of the material. For the calculation of the equivalent stress the influence of friction and internal stresses in the material have to be taken into account. The local stress level in the half space strongly depends on friction and internal stresses. It will be demonstrated, that it is necessary to have a look at a greater part of the full half space to find the maximum stress level.

Thermomechanical Fatigue Behavior of a Quasi-lsotropic SCS-6/Ti-15-3 Metal Matrix Composite

1995 ◽  
Vol 117 (1) ◽  
pp. 109-117 ◽  
Author(s):  
K. A. Hart ◽  
S. Mall
Keyword(s):  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Stress Level ◽  
Metal Matrix ◽  
Maximum Stress ◽  
Fatigue Behavior ◽  
Thermomechanical Fatigue ◽  
Fatigue Tests ◽  
Microscopic Evaluation ◽  
Observed Damage

The response of a quasi-isotropic laminate of metal matrix composite, SCS-6/Ti-15-3 in a thermomechanical fatigue (TMF) environment was investigated. To achieve this, three sets of fatigue tests were conducted: 1) in-phase TMF (IP-TMF), 2) out-of-phase TMF (OP-TMF), and 3) isothermal fatigue (IF). The fatigue response was dependent on the test condition and the maximum stress level during cycling. The IF, IP-TMF, and OP-TMF conditions yielded shortest fatigue life at higher, intermediate and lower stress levels, respectively. Examination of the failure mode through the variation of strain or modulus during cycling, and post-mortem microscopic evaluation revealed that it was dependent on the fatigue condition and applied stress level. Higher stresses, mostly with IP-TMF and IF conditions, produced a primarily fiber dominated failure. Lower stresses, mostly with the OP-TMF condition, produced a matrix dominated failure. Also, an empirical model based on the observed damage mechanisms was developed to represent the fatigue lives for the three conditions examined here.

The effect of seismic-like induced cyclic loading on damage response of sandstone and granite

2020 ◽  
Author(s):  
Rashid Geranmayeh Vaneghi ◽  
Arcady V. Dyskin ◽  
Klaus Thoeni ◽  
Mostafa Sharifzadeh ◽  
Mohammad Sarmadivaleh
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Stress Level ◽  
Maximum Stress ◽  
Low Frequency ◽  
Life Time ◽  
Rock Types ◽  
Axial Tensile ◽  
Stress Cycles ◽  
Level Loading

<p>The detailed study of rock response to cyclic loading induced by natural phenomena, such as seismic and volcanic activities, and man-made explosions and excavation is necessary for failure prediction and hazard mitigation. The effect of the maximum stress level, loading amplitude, and frequency of stress cycles on the fatigue life and failure mechanisms of two microstructurally different rocks of granite/granodiorite and sandstone is investigated. Test data obtained from comprehensive experiments conducted on these rock types incorporated with the results of previous studies show that the fatigue life time of both rock types increases with a decrease in either maximum stress level or stress amplitude. Nevertheless, the fatigue strength threshold of hard rocks like granite is generally lower than that of soft rocks like sandstone. The study also shows that the low-frequency cyclic loading has more damaging effect on both rock types than the high frequency loading. This investigation demonstrates that the failure mechanism of rocks under cyclic loading is characterized by the development of more tensile microcracks compared to the monotonic loading and the opening and extension of the axial tensile microfractures are more evident at higher maximum stresses or loading amplitudes or at lower loading frequencies. The results presented in this study will contribute to a deeper understanding of the fatigue responses of sandstone and granite to seismic-generated loading–unloading processes under different conditions of stress cycles.</p>

Experimental Study on Fatigue Crack Propagation of Glare3-3/2 with Mechanics Properties

2012 ◽  
Vol 600 ◽  
pp. 273-278
Author(s):  
Zong Hong Xie ◽  
Tian Jiao Zhao ◽  
Rui Wu
Keyword(s):  
Growth Rate ◽  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Stress Level ◽  
Maximum Stress ◽  
Fatigue Tests

This study is to investigate the fatigue crack growth behavior of Glare3-3/2 under various stress levels. The Glare3-3/2 specimen consists of three 2024-T3 aluminum alloy sheets and two layers of glass/epoxy composite lamina. Tensile-tensile cyclic fatigue tests were conducted on centrally notched specimen at four stress levels with various maximum values. A digital camera system was used to take photos of the propagating cracks on both sides of the specimen. Image processing software was adopted to accurately measure the length of the cracks on each photo. The test results show that 1) Compared to 2024-T3 aluminum alloy, the fatigue properties of Glare3-3/2 are much better: under the same loading condition with maximum stress level of 120MPa, the crack growth rate of Glare3-3/2 is roughly 5% of the corresponding value of 2024-T3 aluminum alloy, while the fatigue life is 4 times higher than that of 2024-T3 aluminum alloy. 2) The maximum stress level shows strong influence on fatigue crack propagation behavior of Glare3-3/2. The value of steady state crack growth rate increases linearly, while the number of load cycles decreases exponentially, with respect to the maximum stress values used in the fatigue tests.

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