scholarly journals Experimental Observation on the Pure Torsional Ratchetting of Polycarbonate Polymer at Room Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Fucong Lu ◽  
Bencheng Zhang ◽  
Bo Wu ◽  
Zhiwen Wu ◽  
Xiao Suo
Keyword(s):  
Cyclic Loading ◽  
Stress Level ◽  
Room Temperature ◽  
Stress Amplitude ◽  
Peak Stress ◽  
Stress Rate ◽  
Mean Stress ◽  
Loading History ◽  
Lower Stress ◽  
Lower Stress Level

The stress-controlled pure torsional cyclic tests are carried out to investigate the torsional ratchetting of polycarbonate (PC) polymer at room temperature. The effects of applied shear mean stress, stress amplitude, stress rate, peak stress hold, and stress history on the torsional ratchetting are discussed. The shear strain of tubular specimen is measured by a noncontact digital image correlation (DIC) apparatus. The results show that the torsional ratchetting of the polymer obviously depends on the applied shear stress level, stress rate, and peak stress hold; the shear ratchetting strain and its rate increase with the increasing mean stress, stress amplitude, and peak stress hold time and with the decreasing stress rate. Moreover, the torsional ratchetting depends on the stress history. A higher stress level cyclic loading history restrains the evolution of torsional ratchetting in the subsequent lower stress level cyclic loading, while the lower stress level cyclic loading history promotes the torsional ratchetting of the subsequent higher level cyclic loading.

Test and Research on Ratchet Effect of 16 Mn Steel under Cyclic Loading

2015 ◽  
Vol 1095 ◽  
pp. 205-208
Author(s):  
Guang Hong Xiao ◽  
Yang Kai Xiang ◽  
Qiu Ling Zhang
Keyword(s):  
Control System ◽  
Cyclic Loading ◽  
Stress Amplitude ◽  
Mean Stress ◽  
Loading History ◽  
Ratchet Effect ◽  
Stress Control ◽  
Mn Steel ◽  
16Mn Steel

The uniaxial and multiaxial non-proportional cyclic experiments of 16Mn steel under stress-control were carried out using MTS809 Series machine and Teststar control system .The influence of stress amplitude, mean stress and their loading history on uniaxial and multiaxial ratcheting is studied.

Test and Research on Ratchet Effect of 16 Mn Steel under Cyclic Loading

2012 ◽  
Vol 476-478 ◽  
pp. 965-968
Author(s):  
Guang Hong Xiao ◽  
Yang Kai Xiang ◽  
Xiao Lei Jia
Keyword(s):  
Control System ◽  
Cyclic Loading ◽  
Stress Amplitude ◽  
Mean Stress ◽  
Loading History ◽  
Ratchet Effect ◽  
Stress Control ◽  
Mn Steel ◽  
16Mn Steel

The uniaxial and multiaxial non-proportional cyclic experiments of 16Mn steel under stress-control were carried out using MTS809 Series machine and Teststar control system .The influence of stress amplitude, mean stress and their loading history on uniaxial and multiaxial ratcheting is studied.

Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Stress Amplitude ◽  
Cyclic Plasticity ◽  
Mean Stress ◽  
Effective Parameters ◽  
Perfect Plasticity ◽  
Residual Stress Relaxation ◽  
Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

Bending Ratcheting Behavior of Zircaloy-4 Alloy at Room Temperature

2013 ◽  
Vol 690-693 ◽  
pp. 1713-1717 ◽  
Author(s):  
Hong Qiang Guo ◽  
Hua Li ◽  
Yi Chen Sun ◽  
Wei Wei Yu
Keyword(s):  
Room Temperature ◽  
Stress Amplitude ◽  
Experimental Results ◽  
Strain Level ◽  
Mean Stress ◽  
Cyclic Tests ◽  
Ratcheting Strain

In this paper, a series of bending cyclic tests under stress controlled were conducted at room temperature on Zircaloy-4 (Zr-4) to investigate its bending ratcheting behavior. The effects of mean stress and stress amplitude on the bending ratcheting behavior were experimentally studied, respectively. The experimental results show that the ratcheting strain of the material is very sensitive to mean stress and stress amplitude. It can be concluded that ratcheting strain level increases with increasing mean stress and stress amplitude.

Experimental Observation on the Uniaxial Cyclic Deformation Behaviour of TA16 Titanium Alloy

2011 ◽  
Vol 415-417 ◽  
pp. 2318-2321 ◽  
Author(s):  
Qian Hua Kan ◽  
Wen Yi Yan ◽  
Guo Zheng Kang ◽  
Su Juan Guo
Keyword(s):  
Titanium Alloy ◽  
Cyclic Loading ◽  
Cyclic Deformation ◽  
Room Temperature ◽  
Stress Ratio ◽  
Stress Amplitude ◽  
Deformation Behaviour ◽  
Ratcheting Strain ◽  
Number Of Cycles ◽  
Stable Material

The cyclic deformation including the ratcheting of TA16 titanium alloy was investigated experimentally at room temperature. Experimental results under symmetrical strain-controlled cyclic loading with various strain amplitudes show that the responded stress amplitude keeps almost unchanged with the increasing number of cycles. It is concluded that TA16 titanium alloy can be regarded as a cyclic stable material. Remarkable ratcheting was also observed under asymmetrical stress-controlled cyclic loading, i.e., ratcheting strain increases with the increasing number of cycles. The ratcheting strain strongly depends on the stress level and increases with the increase of applied mean stress, stress amplitude and stress ratio. These findings are useful to reasonably model the cyclic deformation of TA16 titanium alloy.

Cyclic Deformation and Fatigue Crack Behavior of Extruded AZ31B Magnesium Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 3056-3061 ◽  
Author(s):  
Shigeki Morita ◽  
Shingo Tanaka ◽  
Nobuyoshi Ohno ◽  
Yuji Kawakami ◽  
Takashi Enjoji
Keyword(s):  
Fatigue Limit ◽  
Axial Load ◽  
Room Temperature ◽  
Secondary Particle ◽  
Stress Amplitude ◽  
Fatigue Cracks ◽  
Hysteresis Loops ◽  
Lower Stress ◽  
Stress Strain ◽  
Deformation Twins

Pseudoelastic behaviors were observed in compressive and tensile loading-unloading tests at room temperature. The large anelastic strains were observed in compressive stress-strain hysteresis loops. The fatigue limit of axial load-controlled fatigue test at 107 cycles was 90MPa at room temperature. The deformation twins were observed in the specimen subjected to the higher stress amplitude of fatigue limit and free deformation twins were observed in the specimen subjected to the lower stress amplitude of fatigue limit. Stress-strain hysteresis loops were linear in tensile and compressive phases at the lower stress amplitude of fatigue limit and the complicated pseudoelastic deformations were observed in tensile and compressive phases at the higher stress amplitude of fatigue limit of axial load-controlled fatigue tests. Compressive mean strain generated by cyclic pseudoelastic deformations at the higher stress amplitude of fatigue limit. Fatigue cracks initiated at the secondary particle/matrix interface or broken secondary particle near the surface. Subsequently, small cracks tended to grow through transgranular.

scholarly journals The influence of stress level on the ratcheting magnitude and progress rate in steel alloys under uniaxial loading conditions

2021 ◽  
Author(s):  
Prasanth Chandrasekar
Keyword(s):  
Cyclic Loading ◽  
Plastic Strain ◽  
Strain Rate ◽  
Loading Condition ◽  
Stress Amplitude ◽  
Fatigue Loading ◽  
Mean Stress ◽  
Cyclic Loading Condition ◽  
Ratcheting Strain ◽  
Cyclic Damage

Engineering materials in their service life undergo symmetric or asymmetric fatigue loading, which leads to fatigue damage in the material. Ratcheting damage is due to the application of mean stress under cyclic loading condition. From deformation behavior perspective, application of mean stress under stress-controlled fatigue loading gives rise to accumulation of plastic strain in the material. Ratcheting strain increases with an increase in applied mean stress and stress amplitude. In addition, ratcheting behavior will increase in cyclic damage with the rise in strain accumulation and it can be illustrated by a shift in the hysteresis loop towards large plastic strain amplitudes. This study focuses on the ratcheting behavior of different steel materials under uniaxial cyclic loading condition and suggests a suitable method to arrest ratcheting by loading the materials at zero ratcheting strain rate condition with specified mean stress and stress amplitudes. The three dimensional surface is created with stress amplitude, mean stress and ratcheting strain rate for different steel materials. This represents a graphical surface zone to study the ratcheting strain rates for various mean stress and stress amplitude combinations.

The effect of the lower stress level on the cyclic creep behavior of an ods superalloy

1991 ◽  
Vol 18 (6) ◽  
pp. 1029-1033
Author(s):  
William L. Kimmerle ◽  
Vincent C. Nardone ◽  
John K. Tien
Keyword(s):  
Stress Level ◽  
Creep Behavior ◽  
Cyclic Creep ◽  
Lower Stress ◽  
Lower Stress Level

Thermal cycling aging effects on the ratcheting behavior of anisotropic conductive film

2015 ◽  
Vol 27 (4) ◽  
pp. 185-194 ◽  
Author(s):  
Hong Gao ◽  
Jianhua Ma ◽  
Lilan Gao ◽  
Dunji Yu ◽  
Jinsheng Sun
Keyword(s):  
Thermal Cycling ◽  
Strain Rate ◽  
Loading Rate ◽  
Stress Amplitude ◽  
Mean Stress ◽  
Loading Conditions ◽  
Loading History ◽  
Adhesive Film ◽  
Content Type ◽  
Ratcheting Strain

Purpose – The purpose of this paper is to determine: how the thermal cycling aging affects the ratcheting behavior of anisotropic conductive adhesive film (ACF); how the loading conditions and loading history affect the ratcheting strain and strain rate of ACF with different thermal cycling aging histories. Design/methodology/approach – The ACF of CP6920F was cured at 190°C in an electro-thermal vacuum drying apparatus for 30 s. The cured specimens were put into the thermal cycling chamber (−40-150°C) for aging to 25, 50, 100, 200 and 500 cycles. A series of uniaxial ratcheting tests of aged ACF after different thermal cycles was carried out under stress control at 80°C. Findings – The ACF subjected to larger number of thermal aging cycles exhibits less ratcheting strain under the same loading conditions. The ACF with the same thermal cycling aging history shows more ratcheting strain and a higher ratcheting strain rate when loaded under a larger mean stress or stress amplitude or a lower loading rate. The ratcheting behavior of aged ACF is found to be more sensitive to the lower loading rate. The higher mean stress (or stress amplitude) enhances the deformation resistance and consequently restrains the ratcheting strain of subsequent cycling with a lower mean stress (or stress amplitude). The prior lower loading rate accelerates the plastic deformation more significantly than the higher one. Originality/value – The influencing trends of thermal cycling aging, loading condition and loading history on ratcheting behavior of ACF are obtained, which is important for the design and safety assessment of ACF joints.

scholarly journals Effects of Varying Mean Stress and Stress Amplitude on the Fatigue of Polysilicon

2003 ◽  
Vol 795 ◽  
Author(s):  
H. Kahn ◽  
R. Ballarini ◽  
A. H. Heuer
Keyword(s):  
Cyclic Loading ◽  
Polycrystalline Silicon ◽  
Stress Amplitude ◽  
Fatigue Behavior ◽  
Monotonic Loading ◽  
Mean Stress ◽  
Bend Strength ◽  
Electrostatic Actuator ◽  
Single Edge ◽  
Physical Mechanisms

ABSTRACTPolycrystalline silicon (polysilicon) single edge-notched fatigue specimens with micrometer-sized dimensions were macromachined and subjected to cyclic loading using an integrated electrostatic actuator. The effects of fatigue were determined by comparing the monotonic bend strength measured after cyclic loading to the monotonic bend strength of specimens that received no cycling. Both strengthening and weakening were observed, depending on the levels of mean stress and fatigue stress amplitude during the cyclic loading. Monotonic loading with similar stress levels prior to bend strength measurements had no effect on measured bend strength. Possible physical mechanisms responsible for this fatigue behavior are discussed.

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