Evaluation of Notch Tip Opening Displacement Using a Composite Crack Profile Approach

1988 ◽  
Vol 16 (1) ◽  
pp. 17 ◽  
Author(s):  
A Wolfenden ◽  
CR Pratap ◽  
RK Pandey
Keyword(s):  
Opening Displacement ◽  
Notch Tip ◽  
Profile Approach ◽  
Crack Profile

Ductile Cracking Evaluation of X80/X100 High Strength Linepipes

2004 ◽  
Author(s):  
Teruki Sadasue ◽  
Satoshi Igi ◽  
Takahiro Kubo ◽  
Nobuyuki Ishikawa ◽  
Shigeru Endo ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Equivalent Plastic Strain ◽  
Base Material ◽  
Prediction Method ◽  
High Strength ◽  
Critical Conditions ◽  
Opening Displacement ◽  
Cracking Behavior ◽  
Surface Flaws ◽  
Notch Tip

The ductile cracking behavior of girth weld joints, in X80 and X100 grade linepipe, was investigated using single edge notched (SENT) specimens, notched round bar (NRB) specimens and wide plate (WP) specimens. FE analyses were carried out to evaluate critical conditions for ductile cracking at the notch tip. The effect of Y/T ratio of base material on ductile cracking for welded joints was also studied. Ductile cracking from the notch tip in WP specimens can be estimated by using the critical equivalent plastic strain, which can be obtained from SENT or NRB specimens. In addition, a simplified prediction method for ductile cracking by using effective opening displacement was proposed and its validity demonstrated by comparison to the equivalent plastic strain at the notch tip. With respect to the influence of material properties on ductile cracking behavior, deformability of joint to ductile cracking was enhanced by reduction of Y/T ratio of base material. Based on the experimental results and FE analyses, pipe design to prevent ductile cracking from surface flaws under large deformation was discussed.

Reconstruction of complex shaped crack from ECT signals based on a fast forward solver using an advanced multi-media element

2020 ◽  
Vol 64 (1-4) ◽  
pp. 621-629
Author(s):  
Yingsong Zhao ◽  
Cherdpong Jomdecha ◽  
Shejuan Xie ◽  
Zhenmao Chen ◽  
Pan Qi ◽  
...  
Keyword(s):  
Coefficient Matrix ◽  
Crack Edge ◽  
Numerical Accuracy ◽  
Gauss Point ◽  
Current Testing ◽  
Efficient Simulation ◽  
Shaped Crack ◽  
Multi Media ◽  
Profile Reconstruction ◽  
Crack Profile

In this paper, the conventional database type fast forward solver for efficient simulation of eddy current testing (ECT) signals is upgraded by using an advanced multi-media finite element (MME) at the crack edge for treating inversion of complex shaped crack. Because the analysis domain is limited at the crack region, the fast forward solver can significantly improve the numerical accuracy and efficiency once the coefficient matrices of the MME can be properly calculated. Instead of the Gauss point classification, a new scheme to calculate the coefficient matrix of the MME is proposed and implemented to upgrade the ECT fast forward solver. To verify its efficiency and the feasibility for reconstruction of complex shaped crack, several cracks were reconstructed through inverse analysis using the new MME scheme. The numerical results proved that the upgraded fast forward solver can give better accuracy for simulating ECT signals, and consequently gives better crack profile reconstruction.

Thermal Analysis of GaN-Based HFET Devices Using the Unit Thermal Profile Approach

2002 ◽  
Vol 389-393 ◽  
pp. 1523-1526
Author(s):  
Jeong Park ◽  
Chin C. Lee ◽  
Jong Wook Kim ◽  
Jae Seung Lee ◽  
Won Sang Lee ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Thermal Profile ◽  
Profile Approach

Ductile Crack Extension Analysis for X80 Bending Deformation Using Damage-Based Model

2014 ◽  
Author(s):  
Satoshi Igi ◽  
Mitsuru Ohata ◽  
Takahiro Sakimoto ◽  
Kenji Oi ◽  
Joe Kondo
Keyword(s):  
Plastic Strain ◽  
Simulation Model ◽  
Crack Growth ◽  
Crack Extension ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Crack Growth Behavior ◽  
Ductile Crack ◽  
Ductile Crack Growth ◽  
Notch Tip

This paper presents experimental and analytical results focusing on the strain limit of X80 linepipe. Ductile crack growth behavior from a girth weld notch is simulated by FE analysis based on a proposed damage model and is compared with the experimental results. The simulation model for ductile crack growth accompanied by penetration through the wall thickness consists of two criteria. One is a criterion for ductile crack initiation from the notch-tip, which is described by the plastic strain at the notch tip, because the onset of ductile cracking can be expressed by constant plastic strain independent of the shape and size of the components and the loading mode. The other is a damage-based criterion for simulating ductile crack extension associated with damage evolution influenced by plastic strain in accordance with the stress triaxiality ahead of the extending crack tip. The proposed simulation model is applicable to prediction of ductile crack growth behaviors from a circumferentially-notched girth welded pipe with high internal pressure, which is subjected to tensile loading or bending (post-buckling) deformation.

A mode I crack with multiple islands of ideal contact between the crack faces: An asymptotic model

2021 ◽  
pp. 108128652110214
Author(s):  
Ivan Argatov
Keyword(s):  
Crack Opening ◽  
Reduction Factor ◽  
Mode I ◽  
Asymptotic Model ◽  
Mode I Crack ◽  
Opening Displacement ◽  
Multiple Contacts ◽  
Scaling Hypothesis ◽  
Penny Shaped Crack ◽  
Crack Faces

The problem of a mode I crack having multiple contacts between the crack faces is considered. In the case of small contact islands of arbitrary shapes, which are arbitrarily located inside the crack, the first-order asymptotic model for the crack opening displacement is constructed using the method of matched asymptotic expansions. The case of a penny-shaped crack has been studied in detail. A scaling hypothesis for the compliance reduction factor is formulated.

Comparison study of crack propagation in rubberized and conventional prestressed concrete sleepers using digital image correlation

2021 ◽  
pp. 095440972110205
Author(s):  
Guoqing Jing ◽  
Du yunchang ◽  
Ruilin You ◽  
Mohammad Siahkouhi
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Prestressed Concrete ◽  
Mouth Opening ◽  
Image Correlation ◽  
Crack Mouth Opening Displacement ◽  
Experimental Program ◽  
Pure Bending ◽  
Opening Displacement ◽  
Rubber Concrete

Rubber concrete (RC) has been confirmed to be suitable for concrete sleeper production. This paper studies the cracking behaviour of conventional and rubber-reinforced concrete sleepers based on the results of an experimental program. The cracking behaviour in the pure bending zone was analysed up to a load of 140 kN. The crack mouth opening displacement (CMOD) was accordingly measured using a digital image correlation (DIC) method. The DIC results show that the rubber prestressed concrete sleeper (RPCS) has a resistance against crack initiation that is 20% greater than that of the conventional prestressed concrete sleeper (CPCS) under the same loading condition; however, due to the higher crack growth rate of the RPCS, the first crack detected by the operator forms at 60 kN, which corresponds to a strength approximately 9% lower compared with the 65 kN load at which the first crack is detected in the CPCS. Before the first crack (60 kN), the RPCS has a deflection 35% lower than that of the CPCS, but after cracking, at loads of 80 kN, 100 kN and 140 kN, the RPCS has a deflection 15%, 4% and 24% higher than that of the CPCS, respectively.

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