scholarly journals Effects of the Vibration Amplitude in Vibratory Stress Relief on the Fatigue Life of Structures

2021 ◽  
Vol 7 (1) ◽  
pp. 56-65
Author(s):  
Cuong Bui Manh ◽  
Duong Nguyen Van ◽  
Si Do Van ◽  
Manh Phan Van ◽  
Van Thao Le
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Vibration Amplitude ◽  
Local Heating ◽  
Stress Relief ◽  
Resonant Frequencies ◽  
Bending Tests ◽  
Maximum Residual Stress ◽  
A36 Steel ◽  
Vibrating Table

This research aims to investigate the effects of vibration amplitude in vibratory stress relief (VSR) on the fatigue strength of structures with residual stress. Experiments are carried out on specimens with residual stress generated by local heating. Flat specimens made of A36 steel are prepared to be suitable for setting up fatigue bending tests on a vibrating table. Several groups of samples are subjected to VSR at resonant frequencies with different acceleration amplitudes. The results show that VSR has an important influence on the residual stress and fatigue limit of steel specimens. The maximum residual stress in the samples is reduced about 73% when the amplitude of vibration acceleration is 57 m/s2. The VSR method can also improve the fatigue limit by up to 14% for steel samples with residual stress.

scholarly journals Residual stress relief in butt-welded 5083 aluminum alloy by local heating

1971 ◽  
Vol 21 (2) ◽  
pp. 80-84
Author(s):  
Eiji TANAKA ◽  
Katsuhiko HIRATA ◽  
Katsuzi TAKEUCHI
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Local Heating ◽  
Stress Relief ◽  
5083 Aluminum Alloy

TEM investigations of surface residual stress relaxation in A12O3 and Al2O3-SiC nanocomposite

1994 ◽  
Vol 52 ◽  
pp. 628-629
Author(s):  
J. Fang ◽  
H. M. Chan ◽  
M. P. Harmer
Keyword(s):  
Residual Stress ◽  
Single Phase ◽  
Stress Relief ◽  
Stress Recovery ◽  
Surface Residual Stress ◽  
Microscopic Mechanism ◽  
Sic Particles ◽  
Annealing Procedure ◽  
The Difference ◽  
Nano Size

It was Niihara et al. who first discovered that the fracture strength of Al2O3 can be increased by incorporating as little as 5 vol.% of nano-size SiC particles (>1000 MPa), and that the strength would be improved further by a simple annealing procedure (>1500 MPa). This discovery has stimulated intense interest on Al2O3/SiC nanocomposites. Recent indentation studies by Fang et al. have shown that residual stress relief was more difficult in the nanocomposite than in pure Al2O3. In the present work, TEM was employed to investigate the microscopic mechanism(s) for the difference in the residual stress recovery in these two materials.Bulk samples of hot-pressed single phase Al2O3, and Al2O3 containing 5 vol.% 0.15 μm SiC particles were simultaneously polished with 15 μm diamond compound. Each sample was cut into two pieces, one of which was subsequently annealed at 1300° for 2 hours in flowing argon. Disks of 3 mm in diameter were cut from bulk samples.

Effect of Pre-Strain and Roller Working on Torsional Fatigue Properties of a Structural Steel

2011 ◽  
Vol 295-297 ◽  
pp. 2227-2230
Author(s):  
Cong Ling Zhou
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Work Hardening ◽  
Compressive Residual Stress ◽  
Strain Ratio ◽  
Fatigue Tests ◽  
The Other ◽  
Fatigue Properties ◽  
Torsional Fatigue ◽  
Stress Work

In this study, fatigue tests have been performed using two kinds of specimens made of 25 steel. One is pre-strained specimen with pre-strain ratio changing from 2% to 8% by tension, the other is roller worked with deformation of 0.5 mm and 1.0 mm in diameter direction. In the case of pre-strained specimen, the fatigue limit increases according to increase of tensile pre-strain, the fatigue limit of 8% pre-strained specimen is 25% higher than that of non-pre-strained one; in the case of roller worked specimen, the fatigue limit of R05 and R10 is 126% and 143% to that of non-roller worked specimen, respectively. These remarkable improvements of fatigue limit would be caused by the existence of compressive residual stress, work-hardening and the elongated microscopic structures.

Effects of Stress-Relief Annealing on the Residual Stress and the Microstructure of TA15 Welded Joint

2016 ◽  
Vol 849 ◽  
pp. 281-286 ◽  
Author(s):  
Teng Ma ◽  
Xiao Yun Song ◽  
Wen Jun Ye ◽  
Song Xiao Hui ◽  
Rui Liu
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Fusion Zone ◽  
Maximum Stress ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Stress Relief ◽  
Welding Zone ◽  
Weave Structure ◽  
Effects Of Stress

The effects of stress-relief annealing on the distribution of residual stress and on the microstructure of TA15 (Ti-6.5Al-2Zr-1Mo-1V) alloy joints by electron beam welding (EBW) were investigated. The results indicated that the microstructure of welded joint presented a transitional change, i.e. basket-weave structure appeared in the fusion zone while equiaxed α structure in base metal. No significant change occurred in microstructure after annealing at 650°C for 2 h. The residual stress in fusion zone was mainly tensile stress and the maximum longitudinal stress value was 473MPa. After annealing, the residual stress near the welded joint exhibited a uniform distribution and the maximum stress droped to 150 MPa. The yield stress and tensile stress of the TA15 welding zone were 1016 MPa and 1100 MPa respectively.

Research on the Effects of Welding Sequence on Welding Residual Stress of High-Speed Train Based on SYSWELD

2011 ◽  
Vol 399-401 ◽  
pp. 1806-1811
Author(s):  
Yong Hong Chen ◽  
Peng Chen ◽  
Ai Qin Tian
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
High Speed ◽  
Element Model ◽  
Welding Residual Stress ◽  
High Speed Train ◽  
Distribution Law ◽  
Element Analysis ◽  
Welding Sequence ◽  
Maximum Residual Stress

The finite element model of the roof of aluminum high-speed train was established, double ellipsoid heat source was employed, and heat elastic-plastic theory was used to simulate welding residual stress of the component under different welding sequence based on the finite element analysis software SYSWELD. The distribution law of welding residual stress was obtained. And the effects of the welding sequence on the value and distribution of residual stress was analyzed. The numerical results showed that the simulation data agree well with experimental test data. The maximum residual stress appears in the weld seam and nearby. The residual stress value decreases far away from the welding center. Welding sequence has a significant impact on the final welding residual stress when welding the roof of aluminum body. The side whose residual stress needs to be controlled should be welded first.

scholarly journals Pengaruh Waktu Penahanan pada Perlakuan Panas Paska Pengelasan terhadap Ketangguhan Sambungan Las Baja

2019 ◽  
Vol 13 (2) ◽  
pp. 80
Author(s):  
Muhamad Fitri ◽  
Bambang Sukiyono ◽  
Martua Limido Simanjuntak
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Local Heating ◽  
Post Weld Heat Treatment ◽  
Impact Testing ◽  
Holding Time ◽  
Aisi 4130 ◽  
The Impact ◽  
Holding Temperature ◽  
Weld Heat

One of the welding methods that is widely used today because it is easier to operate, more practical in its use, can be used for all welding positions and more efficient is called Shield Metal Arc Welding (SMAW). In this welding, the base metal and filler metal will experience thermal cycles which lead to local heating and cooling processes resulting in residual stress and distortion in the material. This residual stress must be removed because it causes a decrease in the mechanical properties of the material. The most widely used method is the thermal method that is by Post Weld Heat Treatment (PWHT). The success of The post-weld heat treatment in removing residual stresses in PWHT is influenced by the holding time. This study aims to examine the effect of holding time on heat treatment, on the weld toughness of steel. In this study, the type of welding used was SMAW welding, the material used was steel AISI 4130, the electrodes used were LB-7018-1 standard application and AWS classification A5.1 E7018-1. The test holding temperature is 650oC. The holding time of testing uses three variables, namely: 2.5 hours, 4.5 hours, 6.5 hours. The Impact testing is done by the Charpy method. From this study, the influence of holding time variation on PWHT holding temperature on the weld strength of AISI 4130 steel was obtained.

Finite Element Simulation Analysis on Residual Stress Relief of 7075 Aluminum Alloy Ring

2021 ◽  
Vol 1032 ◽  
pp. 135-140
Author(s):  
Shao Feng Wu ◽  
Xiang Sheng Gao ◽  
Xian Rang Zhang ◽  
Han Jun Gao
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Simulation Analysis ◽  
Material Model ◽  
Stress Relief ◽  
Isotropic Hardening ◽  
7075 Aluminum Alloy ◽  
Vibration Stress ◽  
Structural Parts ◽  
Creep Constitutive Model

Vibration stress relief (VSR) and thermal stress relief (TSR) are important method to eliminate the residual stress of structural parts. The thermal vibratory stress relief (TVSR) is a new method to decrease and homogenize the residual stress. Based on the stress relaxation tests and the equivalent vibration equation of modal analysis, the creep constitutive model and the bilinear isotropic hardening plasticity material model (BISO) are combined to establish the numerical simulation model of TVSR of 7075 aluminum alloy ring part. The simulation results show that four different initial blank residual stress levels are obtained after quenching process, and the residual stress elimination and homogenization effect of TSR and TVSR is better than that of VSR. TVSR has a better effect on both residual stress elimination and homogenization, and the residual stress relief rate can reach more than 20%.

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