Numerical and Experimental Studies of Residual Stresses in Cold Expanded Holes

2012 ◽  
Vol 488-489 ◽  
pp. 1282-1287 ◽  
Author(s):  
H.D. Gopalakrishna ◽  
Vinod M. Srinivasa
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Strain Gauges ◽  
Maximum Deviation ◽  
Element Analysis ◽  
Hole Expansion ◽  
Al 2024

This paper presents the numerical and experimental studies of the residual stresses in Al 2024 T3 specimens due to cold hole expansion (CHE) using ball and taper mandrel techniques. A three dimensional, non-linear finite element analysis has been performed to simulate the CHE process and experiments were conducted to determine the residual stresses due to CHE with 2 - 6 % expansion of holes. The residual stresses were determined experimentally by employing strain gauges around the hole during the expansion. Experimental and Finite Element Analysis (FEA) results showed that the residual stresses increased up to 5 % of hole expansion and decreased further in both the techniques of CHE and the same were greater in case of tapered mandrel than that of ball mandrel method. At the optimum expansion of 5%, the FE predictions and experimental results concurred with each other with a maximum deviation of 2%.

Fast Three-Dimensional Finite Element Analysis of Weld Overlay Application on a Formed Feeder Elbow

2011 ◽  
Author(s):  
Francis H. Ku ◽  
Pete C. Riccardella
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Nuclear Reactor ◽  
Three Dimensional ◽  
Fe Method ◽  
Element Analysis ◽  
Weld Overlay ◽  
Welding Processes

This paper presents a fast finite element analysis (FEA) model to efficiently predict the residual stresses in a feeder elbow in a CANDU nuclear reactor coolant system throughout the various stages of the manufacturing and welding processes, including elbow forming, Grayloc hub weld, and weld overlay application. The finite element (FE) method employs optimized FEA procedure along with three-dimensional (3-D) elastic-plastic technology and large deformation capability to predict the residual stresses due to the feeder forming and various welding processes. The results demonstrate that the fast FEA method captures the residual stress trends with acceptable accuracy and, hence, provides an efficient and practical tool for performing complicated parametric 3-D weld residual stress studies.

scholarly journals Three-dimensional finite element simulation of residual stresses in UIC60 rails during the quenching process

2017 ◽  
Vol 21 (3) ◽  
pp. 1301-1307 ◽  
Author(s):  
Nejad Masoudi ◽  
Mahmoud Shariati ◽  
Khalil Farhangdoost
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Analysis Model ◽  
Element Analysis ◽  
Quenching Process ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The aim of this paper is to develop means to predict accurately the residual stresses due to quenching process of an UIC60 rail. A 3-D non-linear stress analysis model has been applied to estimate stress fields of an UIC60 rail in the quenching process. A cooling mechanism with water spray is simulated applying the elastic-plastic finite element analysis for the rail. The 3-D finite element analysis results of the studies presented in this paper are needed to describe the initial conditions for analyses of how the service conditions may act to change the as-manufactured stress field.

Experimental Study and Finite Element Analysis on RPC Footwalk Braces

2006 ◽  
Vol 302-303 ◽  
pp. 713-719
Author(s):  
Zhi Gang Yan ◽  
Gui Ping Yan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Safety Margin ◽  
Experimental Results ◽  
Element Analysis ◽  
Three Dimensional Finite Element ◽  
Reactive Powder

In this paper, a series of Reactive powder concrete (RPC) footwalk braces without conventional steel bars are designed for the Qing-Zang railway. Experimental studies on the braces are conducted in order to test the mechanical character of the braces. Totally eight RPC footwalk braces are experimentally measured with static load. According to the analysis of the experimental results, the ratio of the crack load got from the experiment to the design load is 2.54 and the deflection ductile coefficient is 2.32. The experimental results show that the mechanical performance of RPC footwalk braces can satisfy the engineering requirements and there is enough safety margin for footwalk braces. A three-dimensional finite element analysis (FEA) is also carried out and the results of FEA are compared with that of the experiments. The results show that the FEA method can be used in designing the RPC footwalk braces.

Three-Dimensional Finite Element Analysis of the Cold Expansion of Fastener Holes in Two Aluminum Alloys

2002 ◽  
Vol 124 (2) ◽  
pp. 140-145 ◽  
Author(s):  
Jidong Kang ◽  
W. Steven Johnson ◽  
David A. Clark
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Aluminum Alloys ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Element Analysis ◽  
Hardening Models ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A three-dimensional finite element analysis is developed for the cold expansion process in two aluminum alloys, 2024-T351 and 7050-T7451. The entire cold working process including hole expansion, elastic recovery, and finish reaming is simulated. Both isotropic hardening and kinematic hardening models are considered in the numerical calculations. The results suggest that a three-dimensional nature exists in the residual stress fields surrounding the hole. There are significant differences in residual stresses at different sections through the thickness. However, residual stress at the surface is shown to remain the same for the different plastic hardening models after the hole has recovered and finish reaming has been performed. The reaming of the material around the hole has slight effect on the maximum value and distribution of residual stresses. A comparison has been drawn between the FEA of average through thickness strain and a previous experimental investigation of strain that utilized neutron diffraction and modified Sachs boring on a 7050 aluminum specimen containing a cold expanded hole. The different methods show very good agreement in the magnitude of strain as well as the general trend. The conclusions obtained here are beneficial to the understanding of the phenomenon of fatigue crack initiation and growth at the perimeter of cold worked holes.

Ductile Fracture Behaviour of Class 2 and 3 LWR Piping and Its Implications for Flaw Evaluation Criteria

2007 ◽  
Vol 120 ◽  
pp. 85-94 ◽  
Author(s):  
Naoki Miura ◽  
Katsumasa Miyazaki ◽  
Masakazu Hisatsune ◽  
Kunio Hasegawa ◽  
Koichi Kashima
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Evaluation Method ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Evaluation Criteria ◽  
Element Analysis ◽  
Reference Stress ◽  
Class 1 ◽  
Fracture Tests

To achieve a rational maintenance program for aged Light Water Reactor components, it is important to establish and to improve the flaw evaluation criteria. The current flaw evaluation criteria such as ASME Boiler and Pressure Vessel Code Section XI are focused on Class 1 piping which usually shows relatively higher toughness. On the other hand, flaw evaluation criteria suitable for Class 2, 3 piping with moderate-toughness are also required because some Class 2, 3 piping systems are as important to plant safety analysis as Class 1 piping. In this study, both analytical and experimental studies were conducted to provide the evaluation method of fracture loads for acceptance criteria for Class 2, 3 piping. Pipe fracture tests by four-point bending were conducted on circumferentially cracked carbon steel pipes with moderate-toughness. The Net-Section Collapse criterion overpredicted experimental maximum loads for through-wall-cracked pipes, which suggested the necessity of Z-factor. Three-dimensional finite element analysis and simplified analysis based on the reference stress method were conducted to complement the limited pipe fracture tests. It was ascertained that the reference stress method always gave moderately conservative fracture loads compared with the finite element analysis and pipe fracture tests as well. Z-factor for Class 2, 3 piping was then derived and formulated using the reference stress method. Z for Class 2, 3 piping was affected by radius-to-thickness ratio, and was higher than Z for Class 1 piping in the present codes.

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