Evolution of Residual Stresses with Fatigue Crack Growth in a Variable Polarity Plasma Arc–Welded Aluminum Alloy Compact Tension Specimen

2008 ◽  
Vol 39 (10) ◽  
pp. 2370-2377 ◽  
Author(s):  
C.D.M. Liljedahl ◽  
O. Zanellato ◽  
L. Edwards ◽  
M.E. Fitzpatrick
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Residual Stresses ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Plasma Arc ◽  
Tension Specimen ◽  
Variable Polarity ◽  
Variable Polarity Plasma Arc

Effects of Specimen Geometry on Fatigue-Crack Growth Rates in Pipeline Steels

2008 ◽  
Author(s):  
J. M. Treinen ◽  
Ph. P. Darcis ◽  
J. D. McColskey ◽  
R. Smith ◽  
J. Merritt
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Specimen Geometry ◽  
Tension Specimen ◽  
Pipeline Steels ◽  
Crack Growth Rates

The effects of specimen geometry on the fatigue crack growth rates (FCGR) in API X65 and X100 pipeline steels were explored by use of the middle tension and compact tension specimen geometries. It was found that the specimen type has little influence on the stage II linear fatigue crack growth region for these steels. Furthermore, the FCGR behavior in the longitudinal and transverse directions was found to be nearly identical for both steels. Also of interest was a comparison of the FCGR results to the BS 7910 design curves, which showed a discrepancy between the results and the standard only at low delta K levels. A finite element analysis of the compliance relationships used to predict the crack lengths during testing of both specimen types revealed that the expression for both the middle tension specimen and the compact tension specimen were found to be valid. Although the curved geometry of the middle tension specimen caused slightly different compliance results, these differences did not appear to affect the FCGR results.

scholarly journals A peridynamic damage-cumulative hybrid model for fatigue cracking

2021 ◽  
Author(s):  
Lanwen WANG ◽  
Xuanyu Sheng ◽  
Jianbin Luo
Keyword(s):  
Fatigue Crack ◽  
Cyclic Loading ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Hybrid Model ◽  
Fatigue Crack Initiation ◽  
Fatigue Cracking ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Tension Specimen

A new peridynamic fatigue damage-cumulative hybrid model is developed in this study, which is modeled by Kinetic Theory of Fracture(KTF) and Paris formula. The compact tension specimen and modified compact tension specimen are used to study the convergence of the fatigue crack growth path and fatigue life. Then constant amplitude cyclic loading and variable amplitude cyclic loading of the specimens are simulated. By comparing with the experimental results, the accuracy of the model is verified. Compared with the fatigue model that only uses KTF, the hybrid model predicts the fatigue crack growth rate more accurately. The model is based on the stress damage criterion in the fatigue crack initiation stage, which can be a basis for fatigue prediction and safety design of components in complex stress state in actual engineering.

scholarly journals Evolution of Microstructure and Mechanical Properties in a Single-Stage Aged 7075 Aluminum Alloy Pulse Variable Polarity Plasma Arc Welded Joint

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 428
Author(s):  
Guowei Li ◽  
Yahong Liang ◽  
Furong Chen ◽  
Yongquan Han ◽  
Li Sun
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
Aging Temperature ◽  
Welded Joint ◽  
Single Stage ◽  
Precipitate Size ◽  
7075 Aluminum Alloy ◽  
Plasma Arc ◽  
Variable Polarity ◽  
Variable Polarity Plasma Arc

A 7075 aluminum alloy was successfully welded by pulsed variable polarity plasma arc welding (PVPPAW) and the single-stage aging behavior of the 7075 aluminum alloy PVPPAW joint was systematically investigated. The results demonstrated that the tensile strength of the welded joints initially increased and then decreased with the increase of the single-stage aging temperature and time. After single-stage aging at 490 °C for 80 min and at 130 °C for 24 h, the tensile strength of the welded joint was 551 MPa, which was increased by 38.5% compared to the as-welded joint. Moreover, the conductivity was 25% international annealed copper standard (IACS) at room temperature, and the resistance to stress corrosion was improved. The main strengthening phases of the weld center were η′ and η phase. The average precipitate size slightly increased with the increase of the single-stage aging temperature, but no obvious change was observed with the increase of the single-stage aging time. The area fraction was initially increased and then decreased with the increase of the single-stage aging temperature and time.

Grey Relational Grade Analysis between Vickers Hardness and Fatigue Crack Growth Data of 2024-T351 Aluminum Alloy

2012 ◽  
Vol 476-478 ◽  
pp. 2435-2439 ◽  
Author(s):  
Chih Chung Ni
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Vickers Hardness ◽  
Compact Tension ◽  
Growth Data ◽  
Alloy Plate ◽  
Grey Relational Grade ◽  
Grey Relational

Compact tension specimens cut from 2024-T351 aluminum-alloy plate were used for Vickers hardness tests under low-force scale and then for fatigue crack growth tests under sinusoidal loads, and the scattered data sets obtained including Vickers hardness, initiation cycle and specimen life, exponent m and intercept C of Paris-Erdogan law were collected as a factor set with five factor series for analysis of grey relational grade. Nominal value method was adopted for the preprocess referred to as grey relational generation to obtained new factor series, and then Hsia’s method was used to calculate the grey relational grades among new factor series. The analyzed result named global grey relational grade in matrix form with dimension of shows three main findings: (1) Vickers hardness has the largest influence on specimen life, and vice versa. (2) Vickers hardness, specimen life, and m have a large influence on each other. (3) C has the least influence on any other factors, and vice versa.

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