Finite Element Simulation of the Sachs Boring Method of Measuring Residual Stresses in Thick-Walled Cylinders

2003 ◽  
Vol 125 (3) ◽  
pp. 274-276 ◽  
Author(s):  
R. R. de Swardt
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Data Reduction ◽  
High Speed ◽  
High Strength ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Element Mesh ◽  
Reduction Methods ◽  
Data Reduction Method

During a recent study the residual strain/stress states through the walls of autofrettaged thick-walled high-strength steel cylinders were measured with neutron diffraction, Sachs boring and the compliance methods (Venter et al., 2000, J. Strain Anal. Eng. Des., 35, pp. 459–469). The Sachs boring method was developed prior to the advent of high speed computers. A new method for the data reduction was proposed. In order to verify the proposed procedure, the Sachs boring experimental method was simulated using finite element modeling. A residual stress field was introduced in the finite element method by elasto-plastic finite element analysis. The physical process of material removal by means of boring was simulated by step-by-step removal of elements from the finite element mesh. Both the traditional and newly proposed data reduction methods were used to calculate the residual stresses. The new data reduction method compares favorably with the traditional method.

Interlaminar Fracture Toughness of a Graphite/Epoxy Multidirectional Composite1

2000 ◽  
Vol 122 (4) ◽  
pp. 428-433 ◽  
Author(s):  
Z. Yang ◽  
C. T. Sun
Keyword(s):  
Fracture Toughness ◽  
Data Reduction ◽  
Crack Extension ◽  
Plate Theory ◽  
Interlaminar Fracture Toughness ◽  
Element Analysis ◽  
Unstable Crack ◽  
Interlaminar Fracture ◽  
Reduction Methods ◽  
Data Reduction Method

In this paper, an experimental investigation on interlaminar fracture behavior and fracture toughness of a graphite/epoxy multidirectional composite laminate is presented using end-notched flexure specimens. The 0/θ interfaces are considered. The interlaminar fracture toughness is obtained and compared using three data reduction methods, i.e., the area method, classical laminated plate theory, and finite element analysis. Results show that the toughness value depends on the data reduction method used. Two different crack-length-to-span ratios are chosen to study how the stable or unstable crack extension influences the toughness measurement. It is observed that the toughness obtained from the tests of stable crack extension is appreciably higher than that from the tests of unstable crack extension. It is also seen that friction resulting from contact of crack surfaces greatly affects the measured toughness in the case of stable crack extension. In addition, effects of the specimen geometry and fiber orientation on the interlaminar fracture toughness are also evaluated. [S0094-4289(00)02804-8]

Finite Element Analysis of Residual Stresses on Butt Welded Joints

2006 ◽  
Author(s):  
Enrico Armentani ◽  
Renato Esposito ◽  
Raffaele Sepe
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Fusion Zone ◽  
Welded Joints ◽  
High Strength Steels ◽  
High Strength ◽  
Heat Of Fusion ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Welding Processes

Localized heating during welding, followed by rapid cooling, usually generates residual stresses in the weld and in the base metal. Residual stresses in welding processes give significant problems in the accurate manufacture of structures because those stresses heavily induce the formation of cracks in the fusion zone in high strength steels. Therefore, estimating the magnitude and distribution of welding residual stresses and characterizing the effects of certain welding conditions on the residual stresses are deemed necessary. In this work, residual stresses and distortions on butt welded joints are numerically evaluated by means of finite element method. The FE analysis allows to highlight and evaluate the stress field and his gradient around the fusion zone of welded joints, higher than any other located in the surrounding area. Temperature-dependent material properties, welding velocity, external mechanism constraints, technique of ‘element birth and death’ and latent heat of fusion are also taken into account. Some numerical results are compared with experimental data showing a very good correlation.

scholarly journals Numerical Evaluation of Advanced Laser Control Strategies Influence on Residual Stresses for Laser Powder Bed Fusion Systems

2020 ◽  
Vol 9 (4) ◽  
pp. 435-445
Author(s):  
Massimo Carraturo ◽  
Brandon Lane ◽  
Ho Yeung ◽  
Stefan Kollmannsberger ◽  
Alessandro Reali ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Laser Power ◽  
High Speed ◽  
Control Strategies ◽  
Element Model ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Element Analysis ◽  
Powder Bed

AbstractProcess-dependent residual stresses are one of the main burdens to a widespread adoption of laser powder bed fusion technology in industry. Residual stresses are directly influenced by process parameters, such as laser path, laser power, and speed. In this work, the influence of various scan speed and laser power control strategies on residual stresses is investigated. A set of nine different laser scan patterns is printed by means of a selective laser melting process on a bare plate of nickel superalloy 625 (IN625). A finite element model is experimentally validated comparing the simulated melt pool areas with high-speed thermal camera in situ measurements. Finite element analysis is then used to evaluate residual stresses for the nine different laser scan control strategies, in order to identify the strategy which minimizes the residual stress magnitude. Numerical results show that a constant power density scan strategy appears the most effective to reduce residual stresses in the considered domain.

A Finite Element Analysis of the Residual Stresses Incurred During Bending of Pipes

2002 ◽  
Author(s):  
C. S. Scott ◽  
M. J. Kozluk
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Small Diameter ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Metal Fabrication ◽  
Cold Bending ◽  
Static Approach ◽  
Explicit Dynamic

This work illustrates the potential for finite element methods to be used in support of metal fabrication processes. The focus is an analysis of the residual stresses incurred during cold bending of small diameter pipes. The pipe was modeled using 3D constant strain elements. The mandrels used to support the pipe and apply the necessary bend forces were modeled using 2D rigid surfaces. Contact surfaces were defined on the outside of the pipe and the inside of the mandrels. The fabrication process was simulated by programming the nodes of one of the mandrels with prescribed velocities. The finite element analysis was performed using H3DMAP, proprietary software that includes a hybrid explicit/dynamic relaxation module. The technique is a quasi-static approach that discounts inertial effects. The finite element analyses are used to predict the residual stresses and plastic strain in the pipe. The studies involve a constant pipe size. Two stress/strain curves are used. The effect of using isotropic or kinematic material hardening models, compressive pre-stressing and differing bending procedures are considered, and results compared. The details of each simulation are shown to influence the calculated residual stress field.

Relaxation of Peening Residual Stresses Due to Cyclic Thermo-Mechanical Overload

2005 ◽  
Vol 127 (2) ◽  
pp. 170-178 ◽  
Author(s):  
S. A. Meguid ◽  
G. Shagal ◽  
J. C. Stranart ◽  
K. M. Liew ◽  
L. S. Ong
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Target Material ◽  
High Strength ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Strain Rate Effects ◽  
Multiple Impact

Shot-peening induced residual stresses can be relaxed due to cyclic loading. This relaxation plays an important role in determining the fatigue life of the peened components. It is therefore the purpose of this study to conduct comprehensive three-dimensional dynamic elasto-plastic finite element analysis of the joint peening treatment and relaxation process. In this regard, a novel symmetry cell is developed and used to model the multiple impact indentations resulting from multiple impingements of a cluster of shots. The model was further extended to integrate the relaxation resulting from cyclic loading at stresses above the yield strength of the material. This integrated model accounts for the main features of both stages by considering strain-rate effects, shot and target inertia and the dependence of the mechanical properties of the target material on temperature. A wide spectra of cyclic mechanical and thermal loads as well as their combinations is considered and the resulting relaxed residual stress field is determined. As an application, the model was used to predict the residual stress relaxation in a high-strength steel target made from AISI 4340 under different peening and thermomechanical cyclic overload.

scholarly journals Effect of vibrations on the residual stress field formation during milling of high-strength aluminum alloys

2021 ◽  
Vol 2094 (4) ◽  
pp. 042026
Author(s):  
A Yu Nikolaev
Keyword(s):  
Aluminum Alloys ◽  
Residual Stresses ◽  
High Speed ◽  
High Strength ◽  
Residual Stress Field ◽  
Ray Method ◽  
High Speed Milling ◽  
Structural Parts ◽  
High Strength Aluminum Alloys ◽  
Field Formation

Abstract The authors examine the influence of high-speed milling on the distribution of residual stresses in parts made of structural high-strength aluminum alloys Al-Cu-Mg, which are the main structural materials in the aerospace industry. Milling was carried out at high cutting speeds. Different tool settings were used to balance the instrument. Plastic deformation occurred in the part’s surface layers. Residual stresses were measured by the X-ray method. It was found that high-speed milling creates residual compressive stresses that are favorable for the operation of the part. The depth of the residual stresses depends on the cutting mode. The article shows the relationship between residual stresses and the type of metalworking tool, processing conditions in structural parts made of high-strength aluminum alloys.

Study on the Local Buckling Behavior of Steel Equal Angle Members under Axial Compression with the Steel Strength Variation

2011 ◽  
Vol 374-377 ◽  
pp. 2430-2436
Author(s):  
Gang Shi ◽  
Zhao Liu ◽  
Yong Zhang ◽  
Yong Jiu Shi ◽  
Yuan Qing Wang
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
High Strength Steel ◽  
Local Buckling ◽  
Steel Structures ◽  
High Strength ◽  
Element Analysis ◽  
Equal Angle ◽  
Buckling Behavior ◽  
Steel Strength

High strength steel sections have been increasingly used in buildings and bridges, and steel angles have also been widely used in many steel structures, especially in transmission towers and long span trusses. However, high strength steel exhibits mechanical properties that are quite different from ordinary strength steel, and hence, the local buckling behavior of steel equal angle members under axial compression varies with the steel strength. However, there is a lack of research on the relationship of the local buckling behavior of steel equal angle members under axial compression with the steel strength. A finite element model is developed in this paper to analyze the local buckling behavior of steel equal angle members under axial compression, and study its relationship with the steel strength and the width-to-thickness ratio of the angle leg. The finite element analysis (FEA) results are compared with the corresponding design method in the American code AISC 360-05, which provides a reference for the related design.

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