Effect of Thermal Residual Stress on the Mechanical Properties of NiAl-Based Composites

1998 ◽  
Vol 552 ◽  
Author(s):  
Hahn Choo ◽  
Mark Bourke ◽  
Philip Nash
Keyword(s):  
Residual Stress ◽  
Yield Strength ◽  
Residual Stresses ◽  
Room Temperature ◽  
Hybrid Composites ◽  
Thermal Residual Stress ◽  
Volume Percent ◽  
Linear Superposition ◽  
Thermal Residual Stresses ◽  
Good Agreement

ABSTRACTNiAl-based hybrid composites containing 5, 15 and 30 volume percent of A12O3 fibers in addition to AIN dispersion particles were fabricated via a powder metallurgy route. The strengthening mechanisms associated with the short A12O3 fiber in NiAl-(A1N)dispersion,-(A12O3)fiber, composite were studied with an emphasis on the effect of thermal residual stress on the compressive strength at room temperature and 1300K. At 300K, the yield strength of the composites was predicted using a linear superposition of the monolithic yield strength, direct fiber strengthening and tensile matrix residual stresses. The prediction shows good agreement with the measured data. The majority of the room temperature strengthening is attributable to the residual stress. At 1300K, the strengthening was achieved only by the load sharing of the fibers and there is no direct influence from the process-induced thermal residual stresses since they were completely relaxed at this temperature.

Effect of Thermal Residual Stresses on Polymer/Metal Interfacial Adhesion

1999 ◽  
Author(s):  
Qizhou Yao ◽  
Jianmin Qu
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Coefficient Of Thermal Expansion ◽  
Interfacial Crack ◽  
Thermal Residual Stress ◽  
Element Analysis ◽  
Thermal Residual Stresses ◽  
Interfacial Cracks ◽  
Cte Mismatch ◽  
Elastic Mismatch

Abstract In this study, the apparent fracture toughness of the interfaces of several epoxy-based polymeric adhesives and metal (aluminum) substrate is experimentally measured. Double layer specimens with initial interfacial cracks are made for four-point bending tests. Thermal residual stresses exist on the interface due to the coefficient of thermal expansion (CTE) mismatch between the underfill and aluminum. Silica fillers are used to modify the CTE of the epoxy-based adhesives so that various levels of interface thermal residual stresses are achieved. Finite element analysis is also performed to quantify the effects of CTE mismatch as well as the elastic mismatch across the interface. It is found that the apparent interfacial toughness is significantly affected by the thermal residual stress, while the effect of elastic mismatch is negligible. In general thermal residual stress undermines the resistance to an interfacial crack. In some cases the residual stress is sufficient to result in adhesive and/or cohesive failure.

scholarly journals An Educational Platform in Structural Mechanics

2013 ◽  
Vol 9 (S8) ◽  
pp. 10 ◽  
Author(s):  
Tiago A. N. Silva ◽  
Maria A. R. Loja
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Level ◽  
Optimization Technique ◽  
Structural Mechanics ◽  
Functionally Graded ◽  
Thermal Residual Stress ◽  
Design Parameters ◽  
Mechanical Resistance ◽  
Thermal Residual Stresses

Thermal residual stresses often arise due to a manufacturing process, involving localised thermal induction, or to the existence of structural components with different thermal expansion coefficients. The existence of thermal residual stresses within a structural member is usually undesired, as it decreases the mechanical resistance of structures. Hence, it is desirable to obtain both a minimum level of residual stresses and smoother stresses transitions in the materials interfaces. Regarding the mitigation of thermal residual stress concentration, the use of materials which properties can vary along the component directions has great interest. This work addresses the use of dual-phase functionally graded materials, which microstructure varies gradually from a material to another according to a given gradation function. On the order hand, it is also addressed the use of a population based optimization algorithm in order to attain the referred minimum stress level. Summarizing, the current work presents an educational platform directed to structural mechanics students, which aims to give the tools to understand both the influence of design parameters in the thermal residual stress level and distribution along the material and the advantages of using a structural optimization technique in order to minimize the drawback thermal residual stresses effects.

Evaluation of the residual stress in stainless steel 304L hydraulically expanded joints

2020 ◽  
pp. 095440892096401
Author(s):  
Ying Hong ◽  
Xuesheng Wang ◽  
Yan Wang ◽  
Zhao Zhang ◽  
Yong Han
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Yield Strength ◽  
Residual Stresses ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
The Finite Element Method ◽  
Power Stations ◽  
Stainless Steel 304 ◽  
Initial Clearance

Stainless steel 304 L tubes are commonly used in the fabrication of heat exchangers for nuclear power stations. The stress corrosion cracking (SCC) of 304 L tubes in hydraulically expanded tube-to-tubesheet joints is the main reason for the failure of heat exchangers. In this study, 304 L hydraulically expanded joint specimens were prepared and the residual stresses of a tube were evaluated with both an experimental method and the finite element method (FEM). The residual stresses in the outer and inner surfaces of the tube were measured by strain gauges. The expanding and unloading processes of the tube-to-tubesheet joints were simulated by the FEM. Furthermore, an SCC test was carried out to verify the results of the experimental measurement and the FEM. There was good agreement between the FEM and the experimental results. The distribution of the residual stress of the tube in the expanded joint was revealed by the FEM. The effects of the expansion pressure, initial tube-to-hole clearance, and yield strength of the tube on the residual stress in the transition zone that lay between the expanded and unexpanded region of the tube were investigated. The results showed that the residual stress of the expanded joint reached the maximum value when the initial clearance was eliminated. The residual stress level decreased with the decrease of the initial tube-to-hole clearance and yield strength. Finally, an effective method that would reduce the residual stress without losing tightness was proposed.

Stress and Fatigue Life Modeling of Cannon Breech Closures Including Effects of Material Strength and Residual Stress

2000 ◽  
Vol 123 (1) ◽  
pp. 150-154
Author(s):  
John H. Underwood ◽  
Michael J. Glennon
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Yield Strength ◽  
Residual Stresses ◽  
Solid Mechanics ◽  
Element Model ◽  
Pressure Vessels ◽  
Material Strength ◽  
Element Analysis

Laboratory fatigue life results are summarized from several test series of high-strength steel cannon breech closure assemblies pressurized by rapid application of hydraulic oil. The tests were performed to determine safe fatigue lives of high-pressure components at the breech end of the cannon and breech assembly. Careful reanalysis of the fatigue life tests provides data for stress and fatigue life models for breech components, over the following ranges of key parameters: 380–745 MPa cyclic internal pressure; 100–160 mm bore diameter cannon pressure vessels; 1040–1170 MPa yield strength A723 steel; no residual stress, shot peen residual stress, overload residual stress. Modeling of applied and residual stresses at the location of the fatigue failure site is performed by elastic-plastic finite element analysis using ABAQUS and by solid mechanics analysis. Shot peen and overload residual stresses are modeled by superposing typical or calculated residual stress distributions on the applied stresses. Overload residual stresses are obtained directly from the finite element model of the breech, with the breech overload applied to the model in the same way as with actual components. Modeling of the fatigue life of the components is based on the fatigue intensity factor concept of Underwood and Parker, a fracture mechanics description of life that accounts for residual stresses, material yield strength and initial defect size. The fatigue life model describes six test conditions in a stress versus life plot with an R2 correlation of 0.94, and shows significantly lower correlation when known variations in yield strength, stress concentration factor, or residual stress are not included in the model input, thus demonstrating the model sensitivity to these variables.

Damage Evolution of the Interphase on C/SiC Composites with CZM Method

2012 ◽  
Vol 166-169 ◽  
pp. 2847-2850
Author(s):  
Yan Jun Chang ◽  
Zhuo Li ◽  
Ke Shi Zhang
Keyword(s):  
Residual Stress ◽  
Damage Evolution ◽  
Fem Analysis ◽  
Matrix Crack ◽  
Thermal Residual Stress ◽  
Analysis Model ◽  
Initial Matrix ◽  
Thermal Residual Stresses ◽  
Initiation And Propagation ◽  
Sic Composites

Considering thermal residual stress and initial matrix crack, the cylinder FEM analysis model for C/SiC tow was established. The cohesive element and damage criterions were introduced to simulation the initiation and propagation of interphase crack processes of C/SiC composites. The thermal residual stresses release with the initial matrix crack and the cracking on interphase. The interphase crack length was dominated by the performance of interphase. Analysis demonstrated that the CZM model can simulate well the thermal residual stress and the delamination of the interphase.

Comparison of Residual Stress Between MIG Welding and Friction Stir Welding

2012 ◽  
Vol 155-156 ◽  
pp. 1218-1222
Author(s):  
Lei Wang ◽  
Mitsuyosi Tsunori
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Stress Distribution ◽  
Yield Strength ◽  
Room Temperature ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Mig Welding ◽  
Friction Stir ◽  
Friction Stir Welding Process

Residual stress distribution plays a very important role in welded structures, the aim of present work is to find out the effect of different welding methods on the residual stress distribution by means of neutron diffraction measurements and FE models simulation. 4 mm thick DH-36 steel plates were butt welded by MIG welding process and 5 mm thick AA 2024 aluminium alloy plates were butt welded by friction stir welding process. Results show that residual stresses of MIG welding process are higher than those of friction stir welding process. The peak residual stress of MIG weld is close to the room temperature uniaxial yield strength of DH-36 while the peak residual stress of friction stir weld is just about 50% of the room temperature uniaxial yield strength of AA2024. The size effect of MIG welded and effect of welding speeds of friction stir welded on the residual stress distribution have also been studied in the paper.

Abrasive Waterjet Peening With Elastic Prestress: Subsurface Residual Stress Distribution

2007 ◽  
Author(s):  
Balaji Sadasivam ◽  
Alpay Hizal ◽  
Dwayne Arola
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Stress Field ◽  
Yield Strength ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
Abrasive Waterjet ◽  
Residual Stress Field ◽  
Surface Residual Stress ◽  
Compressive Residual Stresses

Recent advances in abrasive waterjet (AWJ) technology have resulted in new processes for surface treatment that are capable of introducing compressive residual stresses with simultaneous changes in the surface texture. While the surface residual stress resulting from AWJ peening has been examined, the subsurface residual stress field resulting from this process has not been evaluated. In the present investigation, the subsurface residual stress distribution resulting from AWJ peening of Ti6Al4V and ASTM A228 steel were studied. Treatments were conducted with the targets subjected to an elastic prestress ranging from 0 to 75% of the substrate yield strength. The surface residual stress ranged from 680 to 1487 MPa for Ti6Al4V and 720 to 1554 MPa for ASTM A228 steel; the depth ranged from 265 to 370 μm for Ti6Al4V and 550 to 680 μm for ASTM A228 steel. Results showed that elastic prestress may be used to increase the surface residual stress in AWJ peened components by up to 100%.

Experimental and numerical study of the longitudinal and transverse residual stresses distribution in the constrained groove pressing process of pure copper sheets

2021 ◽  
pp. 146442072110418
Author(s):  
MH Tavajjohi ◽  
M Honarpisheh
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Numerical Study ◽  
Pure Copper ◽  
Accurate Method ◽  
Contour Method ◽  
Average Error ◽  
Finite Element Software ◽  
Pressing Process ◽  
Good Agreement

In this research, the residual stresses distribution resulting from one of the severe plastic deformation methods called Constrained Groove Pressing in pure copper sheets has been studied experimentally and numerically. For this purpose, after the initial preparation of each sample, the mentioned process is applied to the samples up to three passes. After each pass, the residual stresses in these samples in both directions of their length and width have been measured experimentally. To measure the residual stresses in these samples, the contour method, which is a relatively new, effective, and accurate method in providing a two-dimensional residual stress map, has been used. The results indicate that the residual stresses on the surfaces of the samples are compressive and by moving towards the central layers of them, these stresses are converted into tensile residual stresses. The distribution of residual stresses along the length and width of the samples is reported to be relatively uniform. In another part of this research, numerical simulation of the Constrained Groove Pressing process in ABAQUS finite element software is discussed. In this simulation, Johnson–Cook model is used as a constitutive model. The average error of residual stress distribution between the simulation and contour method was about 18% which shown a good agreement.

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