1253 Dependence of Notch Strength Ratio on Stress Triaxiality

2008 ◽  
Vol 2008.1 (0) ◽  
pp. 181-182
Author(s):  
Makoto OHASHI
Keyword(s):  
Stress Triaxiality ◽  
Strength Ratio ◽  
Notch Strength

scholarly journals Study on notch tensile properties of Magnetically Impelled Arc Butt (MIAB) welded carbon steel tubes

2021 ◽  
Vol 2070 (1) ◽  
pp. 012194
Author(s):  
R Sivasankari ◽  
V Balusamy ◽  
G Buvanashekaran
Keyword(s):  
Tensile Strength ◽  
Carbon Steel ◽  
Short Pulse ◽  
Welding Process ◽  
Weld Interface ◽  
Strength Ratio ◽  
Uniform Heating ◽  
Notch Tensile Strength ◽  
Miab Welding ◽  
Notch Strength

Abstract Magnetically Impelled Arc Butt (MIAB) welding is a pressure welding process that uses the circumferential rotating arc to cause uniform heating of the faying surfaces. In this work, notched tensile testing of MIAB welded Carbon steel was carried out to determine the notch sensitivity of Thermo-Mechanically Affected Zones (TMAZ) and to compare the notch tensile property of these zones with the base metal property. In MIAB welding, after sufficient melting of the faying surface, a short pulse of high current is applied to expel the molten metal and impurities from the interface before welding. Insufficient expulsion and formation of Light Band (LB) zone at weld interface resulted in lower Notch Tensile Strength (NTS). Incomplete expulsion with lower upset current at the weld interface contributes to lower Normalized Notch Strength Ratio. Instead higher upset current contributed to higher NTS due to complete expulsion and stronger acicular ferrite formation. Other TMAZs away from the weld interface showed higher notch tensile strength with Notch Strength Ratio (NSR) and Normalized Notch Tensile Strength Ratio (NTSN) greater than unity.

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.

scholarly journals Comparison of Modified Mohr–Coulomb Model and Bai–Wierzbicki Model for Constructing 3D Ductile Fracture Envelope of AA6063

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Jianye Gao ◽  
Tao He ◽  
Yuanming Huo ◽  
Miao Song ◽  
Tingting Yao ◽  
...  
Keyword(s):  
Ductile Fracture ◽  
Fracture Criterion ◽  
Fracture Strain ◽  
Stress Triaxiality ◽  
Ductile Fracture Criterion ◽  
Forming Process ◽  
Tension Tests ◽  
Wide Range ◽  
Round Bar ◽  
Fracture Envelope

AbstractDuctile fracture of metal often occurs in the plastic forming process of parts. The establishment of ductile fracture criterion can effectively guide the selection of process parameters and avoid ductile fracture of parts during machining. The 3D ductile fracture envelope of AA6063-T6 was developed to predict and prevent its fracture. Smooth round bar tension tests were performed to characterize the flow stress, and a series of experiments were conducted to characterize the ductile fracture firstly, such as notched round bar tension tests, compression tests and torsion tests. These tests cover a wide range of stress triaxiality (ST) and Lode parameter (LP) to calibrate the ductile fracture criterion. Plasticity modeling was performed, and the predicted results were compared with corresponding experimental data to verify the plasticity model after these experiments. Then the relationship between ductile fracture strain and ST with LP was constructed using the modified Mohr–Coulomb (MMC) model and Bai-Wierzbicki (BW) model to develop the 3D ductile fracture envelope. Finally, two ductile damage models were proposed based on the 3D fracture envelope of AA6063. Through the comparison of the two models, it was found that BW model had better fitting effect, and the sum of squares of residual error of BW model was 0.9901. The two models had relatively large errors in predicting the fracture strain of SRB tensile test and torsion test, but both of the predicting error of both two models were within the acceptable range of 15%. In the process of finite element simulation, the evolution process of ductile fracture can be well simulated by the two models. However, BW model can predict the location of fracture more accurately than MMC model.

scholarly journals The Relationship between Scapular Upward Rotation and Shoulder Internal and External Rotation Isokinetic Strength in Professional Baseball Pitchers

Healthcare ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 759
Author(s):  
Byung Gon Kim ◽  
Seung Kil Lim ◽  
Sunga Kong
Keyword(s):  
External Rotation ◽  
Professional Baseball ◽  
Isokinetic Strength ◽  
Strength Ratio ◽  
Shoulder Injury ◽  
Isokinetic Dynamometer ◽  
Normal Range ◽  
History Of ◽  
Baseball Pitchers ◽  
The Relationship

This study aims to assess the relationship between scapular upward rotation (SUR) across varying humeral-elevation angles (HEAs) and shoulder isokinetic strength and ratio in professional baseball pitchers. The subjects were professional baseball pitchers (n = 16) without a history of shoulder injury in the last six months. The subject’s SUR angles were measured with the humerus elevated at HEAs of 0° (at rest), 60°, 90°, and 120° to the scapular plane. Shoulder isokinetic strength was evaluated for shoulder internal rotation (IR) and external rotation (ER) strength (PT%BW and TW%BW), and the ER/IR strength ratios were determined at 60, 120 and 180°/s using an isokinetic dynamometer. The SUR angle at an HEA of 0° was positively correlated with IR strength at 120°/s (r = 0.535) and 180°/s (r = 0.522). The SUR angle at an HEA of 60° was negatively correlated with the ER/IR strength ratios at 60°/s (r = −0.505) and 120°/s (r = −0.500). The SUR angle at an HEA of 90° was negatively correlated with the ER/IR strength ratios at 60°/s (r = −0.574; r = −0.554) and 120°/s (r = −0.521; r = −0.589) as well as with ER strength at 180°/s (r = −0.591, r = −0.556). The SUR angle at an HEA of 120° was negatively correlated with ER strength at 60°/s (r = −0.558), 120°/s (r = −0.504; r = −0.524), and 180°/s (r = −0.543) and the ER/IR strength ratio at 60°/s (r = −0.517). In this study, we found that the ratio of isokinetic strength between ER and IR became closer to the normal range on increasing the SUR angle. In particular, an HEA of 90°, which resembles the pitching motion, showed a clear relationship between SUR, shoulder ER, and the ratio of ER/IR isokinetic strength in professional baseball pitchers.

Sign in / Sign up

Export Citation Format

Share Document