The Effect of Welding Residual Stress Distribution in Thickness Direction With Thick Steel Plate to Identification of Fracture Toughness

2016 ◽  
Author(s):  
Gyubaek An ◽  
Wanchuck Woo ◽  
Jeongung Park
Keyword(s):  
Residual Stress ◽  
Crack Propagation ◽  
Steel Plate ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Steel Plates ◽  
Propagation Path ◽  
Crack Propagation Path ◽  
Flux Cored Arc Welding ◽  
Thick Steel

Along with the rapid increase in the size of welding structures, the steel plate used for structure has been increased in thickness. Especially, the growing capacity of large scale ships such as container ships has led to an increase in the thickness and the strength of steel plates for shipbuilding. The toughness and the resistance to brittle fractures of the steel plate tend to decrease for thick plates, which is a result of the so-called thickness effect. Steel plates with 80mm thickness were used and two welding processes, which are flux cored arc welding (FCAW) process and electron gas welding process (EGW), were used to produce full thickness weld joints. To evaluate of brittle crack propagation path, measurement of welding residual stress in both welded joint. In this study, it was aimed to investigate the effect of welding variables on the crack arrest toughness and crack propagation path of thick steel plate welds. Quantitative analysis by temperature gradient ESSO test was conducted to clarify the effect of welding variables for flux cored arc welding (FCAW) and electro gas welding (EGW) joint of thick steel plates with the thickness of 50 and 80mm. Also, welding residual stress was measured for evaluate of welding residual stress effect in both welding process in brittle crack propagation path using neutron science analysis.

Analysis on the Welding Thermal Field and Residual Stress of Thick Plate

2015 ◽  
Vol 1095 ◽  
pp. 693-697
Author(s):  
Jiu Hong Jiang ◽  
Qiang Wang ◽  
Wen Lv
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Thick Plate ◽  
Thermal Field ◽  
Welding Process ◽  
Source Model ◽  
Simulation Software ◽  
Welding Residual Stress ◽  
Element Simulation ◽  
Thick Steel

A 60mm Q345 rigid thick plate with V groove welding connection was modeled in order to simulate the welding residual stress by finite element method. Both element birth and death technique and double ellipse heat source model were introduced to simulate the welding process. The welding thermal field and residual stress of thick steel plate were analyzed by finite element simulation software ANSYS.Then the thermal field and residual stress distribution were visually demonstrated. The result shows that the thermal field shaped like a spindle during welding period and the residual stress at the mid-section in lateral, longitudinal and thickness direction of the welding joint is lower than the stress at the surface of the welding connection.

An Alternative Technique to Evaluate Crack Propagation Path in Hyperelastic Materials

2012 ◽  
Vol 40 (1) ◽  
pp. 42-58 ◽  
Author(s):  
R. R. M. Ozelo ◽  
P. Sollero ◽  
A. L. A. Costa
Keyword(s):  
Constitutive Model ◽  
Crack Propagation ◽  
Experimental Tests ◽  
Growth Direction ◽  
Propagation Path ◽  
J Integral ◽  
Alternative Technique ◽  
Crack Propagation Path ◽  
Hyperelastic Materials ◽  
Material Constitutive Model

Abstract REFERENCE: R. R. M. Ozelo, P. Sollero, and A. L. A. Costa, “An Alternative Technique to Evaluate Crack Propagation Path in Hyperelastic Materials,” Tire Science and Technology, TSTCA, Vol. 40, No. 1, January–March 2012, pp. 42–58. ABSTRACT: The analysis of crack propagation in tires aims to provide safety and reliable life prediction. Tire materials are usually nonlinear and present a hyperelastic behavior. Therefore, the use of nonlinear fracture mechanics theory and a hyperelastic material constitutive model are necessary. The material constitutive model used in this work is the Mooney–Rivlin. There are many techniques available to evaluate the crack propagation path in linear elastic materials and estimate the growth direction. However, most of these techniques are not applicable to hyperelastic materials. This paper presents an alternative technique for modeling crack propagation in hyperelastic materials, based in the J-Integral, to evaluate the crack path. The J-Integral is an energy-based parameter and is applicable to nonlinear materials. The technique was applied using abaqus software and compared to experimental tests.

Numerical simulation of the effect of ultrasonic impact treatment on welding residual stress

2021 ◽  
pp. 2150175
Author(s):  
Tao Mo ◽  
Jingqing Chen ◽  
Pengju Zhang ◽  
Wenqian Bai ◽  
Xiao Mu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Compressive Stress ◽  
Welded Joints ◽  
Welding Process ◽  
Residual Compressive Stress ◽  
Welding Residual Stress ◽  
304 Stainless Steel ◽  
Residual Tensile Stress ◽  
Ultrasonic Impact Treatment

Ultrasonic impact treatment (UIT) is an effective method that has been widely applied in welding structure to improve the fatigue properties of materials. It combines mechanical impact and ultrasonic vibration to produce plastic deformation on the weld joints surface, which introduces beneficial compressive residual stress distribution. To evaluate the effect of UIT technology on alleviating the residual stress of welded joints, a novel numerical analysis method based on the inherent strain theory is proposed to simulate the stress superposition of welding and subsequent UIT process of 304 stainless steel. Meanwhile, the experiment according to the process was carried out to verify the simulation of residual stress values before and after UIT. By the results, optimization of UIT application could effectively reduce the residual stress concentration after welding process. Residual tensile stress of welded joints after UIT is transformed into residual compressive stress. UIT formed a residual compressive stress layer with a thickness of about 0.13 mm on the plate. The numerical simulation results are consistent with the experimental results. The work in this paper could provide theoretical basis and technical support for the reasonable evaluation of the ultrasonic impact on residual stress elimination and mechanical properties improvement of welded joints.

Prediction Method of Three‐Dimensional Crack Propagation Path Based on Deep Learning Application

2020 ◽  
pp. 2001043
Author(s):  
Junxia Wang ◽  
Yuanjie Zheng ◽  
Rong Luo ◽  
Jun Ma ◽  
Yingjie Peng ◽  
...  
Keyword(s):  
Deep Learning ◽  
Crack Propagation ◽  
Three Dimensional ◽  
Prediction Method ◽  
Propagation Path ◽  
Crack Propagation Path

scholarly journals Evolution of Welding Residual Stresses within Cladding and Substrate during Electroslag Strip Cladding

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4126
Author(s):  
Mu Qin ◽  
Guangxu Cheng ◽  
Qing Li ◽  
Jianxiao Zhang
Keyword(s):  
Residual Stress ◽  
Classical Model ◽  
Stress Gradient ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Oil Refining ◽  
Substrate Thickness ◽  
Preheat Temperature ◽  
Cladding Layer ◽  
Hydrogenation Reactor

Hydrogenation reactors are important oil-refining equipment that operate in high-temperature and high-pressure hydrogen environments and are commonly composed of 2.25Cr–1Mo–0.25V steel. For a hydrogenation reactor with a plate-welding structure, the processes and effects of welding residual stress (WRS) are very complicated due to the complexity of the welding structure. These complex welding residual stress distributions affect the service life of the equipment. This study investigates the evolution of welding residual stress during weld-overlay cladding for hydrogenation reactors using the finite element method (FEM). A blind hole method is applied to verify the proposed model. Unlike the classical model, WRS distribution in a cladding/substrate system in this study was found to be divided into three regions: the cladding layer, the stress-affected layer (SAL), and the substrate in this study. The SAL is defined as region coupling affected by the stresses of the cladding layer and substrate at the same time. The evolution of residual stress in these three regions was thoroughly analyzed in three steps with respect to the plastic-strain state of the SAL. Residual stress was rapidly generated in Stage 1, reaching about −440 MPa compression stress in the SAL region at the end of this stage after 2.5 s. After cooling for 154 s, at the end of Stage 2, the WRS distribution was fundamentally shaped except for in the cladding layer. The interface between the cladding layer and substrate is the most heavily damaged region due to the severe stress gradient and drastic change in WRS during the welding process. The effects of substrate thickness and preheat temperature were evaluated. The final WRS in the cladding layer first increased with the increase in substrate thickness, and then started to decline when substrate thickness reached a large-enough value. WRS magnitudes in the substrate and SAL decreased with the increase in preheat temperature and substrate thickness. Compressive WRS in the cladding layer, on the other hand, increased with the increase in preheat temperature.

scholarly journals Controlling the Crack Propagation Path of the Veil Interleaved Composite by Fusion-Bonded Dots

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1260 ◽  
Author(s):  
Guangchang Chen ◽  
Jindong Zhang ◽  
Gang Liu ◽  
Puhui Chen ◽  
Miaocai Guo
Keyword(s):  
Crack Propagation ◽  
Propagation Path ◽  
Mode I ◽  
Fiber Breakage ◽  
Fracture Path ◽  
Interlaminar Fracture ◽  
Crack Propagation Path ◽  
Pull Out ◽  
Continuous Carbon Fiber ◽  
The Veil

This study investigated the effect of the fusion-bonded dots of veil interleaves on the crack propagation path of the interlaminar fracture of continuous carbon fiber reinforced epoxy resin. Two thin fiber layers (i.e., nylon veil (NV) with fusion-bonded dots and Kevlar veil (KV) physically stacked by fibers) were used to toughen composites as interleaves. Result shows that the existence of fusion-bonded dots strongly influenced the crack propagation and changed the interlaminar fracture mechanism. The Mode I fracture path of the nylon veil interleaved composite (NVIC) could propagate in the plane where the dots were located, whereas the path of the Kevlar veil interleaved composite (KVIC) randomly deflected inside the interlayer without the pre-cracking of the dots. The improvement of Mode I toughness was mainly based on fiber bridging and the resulting fiber breakage and pull-out. Fiber breakage was often observed for NVIC, whereas fiber pull-out was the main mechanism for KVIC. For the Mode II fracture path, the fusion-bonded NV dots guided the fracture path largely deflected inside the interlayer, causing the breakage of tough nylon fibers. The fracture path of the physically stacked KVIC occurred at one carbon ply/interlayer interface and only slightly deflected at fiber overlapped regions. Moreover, the fiber pull-out was often observed.

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