scholarly journals Estimation of C* Integral for Mismatched Welded Compact Tension Specimen

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7491
Author(s):  
Marko Katinić ◽  
Dorian Turk ◽  
Pejo Konjatić ◽  
Dražan Kozak
Keyword(s):  
Finite Element ◽  
Heat Affected Zone ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Tension Specimen ◽  
Type Iv ◽  
Material Homogeneity ◽  
Severe Type ◽  
Modified Equation

The C* integral for the compact tension (CT) specimen is calculated using the estimation equation in ASTM E1457-15. This equation was developed based on the assumption of material homogeneity and is not applicable to a welded CT specimen. In this paper, a modified equation for estimating the C* integral for a welded compact tension (CT) specimen under creep conditions is proposed. The proposed equation is defined on the basis of systematically conducted extensive finite element (FE) analyses using the ABAQUS program. A crack in the welded CT specimen is located in the center of the heat-affected zone (HAZ), because the most severe type IV cracks are located in the HAZ. The results obtained by the analysis show that the equation for estimating the C* integral in ASTM E1457-15 can underestimate the value of the C* integral for creep-soft HAZ and overestimate for creep-hard HAZ. Therefore, the proposed modified equation is suitable for describing the creep crack growth (CCG) of welded specimens.

Stress Distribution in Be Compact Tension Specimen

2007 ◽  
Vol 561-565 ◽  
pp. 2033-2036
Author(s):  
Rui Wen Li ◽  
Ping Dong
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Tension Specimen ◽  
X Ray ◽  
Measured Stress ◽  
Local Stresses ◽  
Fracture Behaviors

Beryllium (Be) is susceptible to introduce stress because it is a brittle metal with a high elastic modular. The compact tension (CT) specimens of beryllium were designed to determinate stress and fracture behaviors. Stress distribution near notch in CT beryllium was measured by the combination of an X-ray stress analysis and a custom-designed load device. The results show that local stresses near notch tip are much higher than those on other area. Thus, stress concentration lead the CT specimens fracture along the notch direction. Residual stresses due to machining are remained. A finite element ( FE ) calculation on the same loaded geometry was made, and the result is agreement with the measured stress distribution near notch.

Dynamic Fracture of Concrete–3D Numerical Study of Compact Tension Specimen

2011 ◽  
Vol 82 ◽  
pp. 39-44 ◽  
Author(s):  
Joško Ožbolt ◽  
Akanshu Sharma ◽  
Hans Wolf Reinhardt
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Crack Velocity ◽  
Loading Rate ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Crack Branching ◽  
Tension Specimen ◽  
Loading Rates ◽  
Inertia Forces

The behavior of concrete structures is strongly influenced by the loading rate. Compared to quasi-static loading concrete loaded by impact loading acts in a different way. First, there is a strain-rate influence on strength, stiffness, and ductility, and, second, there are inertia forces activated. Both influences are clearly demonstrated in experiments. For concrete structures, which exhibit damage and fracture phenomena, the failure mode and cracking pattern depend on loading rate. Moreover, theoretical and experimental investigations indicate that after the crack reaches critical speed of propagation there is crack branching. The present paper focuses on 3D finite-element study of the crack propagation of the concrete compact tension specimen. The rate sensitive microplane model is used as a constitutive law for concrete. The strain-rate influence is captured by the activation energy theory. Inertia forces are implicitly accounted for through dynamic finite element analysis. The results of the study show that the fracture of the specimen strongly depends on the loading rate. For relatively low loading rates there is a single crack due to the mode-I fracture. However, with the increase of loading rate crack branching is observed. Up to certain threshold (critical) loading rate the maximal crack velocity increases with increase of loading rate, however, for higher loading rates maximal velocity of the crack propagation becomes independent of the loading rate. The critical crack velocity at the onset of crack branching is found to be approximately 500 to 600 m/s.

Measurements of Residual Stresses in 316 Stainless Steel Weldments

2010 ◽  
Author(s):  
C. M. Davies ◽  
D. Hughes ◽  
R. C. Wimpory ◽  
David W. Dean ◽  
K. M. Nikbin
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Crack Growth ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Stress Distributions ◽  
Tension Specimen ◽  
Creep Crack ◽  
Term Creep

Neutron diffraction measurements have been performed to quantify the residual stresses distributions in austenitic type 316 stainless steel Manual Metal Arc (MMA) weldment sections, which are similar to those used in creep crack growth testing. Measurements have been taken along the expected crack path in these samples to determine the influence of residual stresses on high temperature crack growth. The influence of EB welding extension pieces onto the weldments sections, in order to increase specimen size, and sample cutting for compact tension specimen manufacture are also examined. Similar stress distributions have been measured in nominally identical MMA weldments sections, where peak stresses of up to 120 MPa have been shown. The effects of the EB weld used to attach extension pieces to the weldments sections dominate over the MMA weldments residual stress distributions in these samples, and increases the peak stresses by up to a factor of three. Significant stress relaxation takes place during compact tension specimen manufacture, and in addition creep strain accumulation will further relax these residual stresses. Residual stress effects are therefore considered to only influence the creep crack initiation period in short-term creep crack growth tests. However, in long-term creep crack growth tests, the residual stresses may also influence subsequent creep crack growth behaviour.

An elastic-plastic finite element analysis of a compact tension specimen

1983 ◽  
Vol 18 (1) ◽  
pp. 69-75 ◽  
Author(s):  
A P Kfouri
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Tip ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Tension Specimen ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Release Technique ◽  
Crack Tip Opening

Results from an elastic-plastic finite element analysis of a compact tension specimen (CTS) are presented and provide information on the growth of crack tip plastic zones, crack tip opening displacements, stresses and strains in the region of the crack tip, and Rice's J integral. The elastic-plastic crack separation energy rate GΔ is also evaluated when the crack extends at various loads by applying a crack tip node release technique.

Measurements of Residual Stress in a Welded Compact Tension Specimen Using the Neutron Diffraction and Slitting Techniques

2010 ◽  
Vol 652 ◽  
pp. 210-215 ◽  
Author(s):  
Foroogh Hosseinzadeh ◽  
P. John Bouchard ◽  
Jonathan A. James
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Significant Contribution ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Tension Specimen ◽  
Residual Stress Field ◽  
Butt Weld ◽  
Crack Driving Force

The residual stress field in a compact tension specimen blank extracted from a non-stress-relieved thick section butt weld has been measured using neutron diffraction and the slitting method. Significant triaxial residual stresses were found in the specimen that is normally assumed to be stress free. Moreover the level of stress was sufficient to make a significant contribution to the crack driving force in creep crack growth tests. The benefits of using more than one measurement technique in such investigations are demonstrated.

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