Residual Stress Analysis in Welding - Transient Thermal Elastoplastic Finite Element Modeling

1996 ◽  
Author(s):  
Dong-Wook Lee ◽  
Sung-Chul Lee ◽  
Hyo-Chol Sin
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Stress Analysis ◽  
Element Modeling ◽  
Residual Stress Analysis ◽  
Transient Thermal

scholarly journals Finite Element Modeling of Residual Stress at Joint Interface of Titanium Alloy and 17-4PH Stainless Steel

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 629
Author(s):  
Nana Kwabena Adomako ◽  
Sung Hoon Kim ◽  
Ji Hong Yoon ◽  
Se-Hwan Lee ◽  
Jeoung Han Kim
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Modeling ◽  
Equivalent Stress ◽  
Stress Gradient ◽  
Joint Interface ◽  
Element Modeling ◽  
Actual Experiment ◽  
Maximum Equivalent Stress

Residual stress is a crucial element in determining the integrity of parts and lifetime of additively manufactured structures. In stainless steel and Ti-6Al-4V fabricated joints, residual stress causes cracking and delamination of the brittle intermetallic joint interface. Knowledge of the degree of residual stress at the joint interface is, therefore, important; however, the available information is limited owing to the joint’s brittle nature and its high failure susceptibility. In this study, the residual stress distribution during the deposition of 17-4PH stainless steel on Ti-6Al-4V alloy was predicted using Simufact additive software based on the finite element modeling technique. A sharp stress gradient was revealed at the joint interface, with compressive stress on the Ti-6Al-4V side and tensile stress on the 17-4PH side. This distribution is attributed to the large difference in the coefficients of thermal expansion of the two metals. The 17-4PH side exhibited maximum equivalent stress of 500 MPa, which was twice that of the Ti-6Al-4V side (240 MPa). This showed good correlation with the thermal residual stress calculations of the alloys. The thermal history predicted via simulation at the joint interface was within the temperature range of 368–477 °C and was highly congruent with that obtained in the actual experiment, approximately 300–450 °C. In the actual experiment, joint delamination occurred, ascribable to the residual stress accumulation and multiple additive manufacturing (AM) thermal cycles on the brittle FeTi and Fe2Ti intermetallic joint interface. The build deflected to the side at an angle of 0.708° after the simulation. This study could serve as a valid reference for engineers to understand the residual stress development in 17-4PH and Ti-6Al-4V joints fabricated with AM.

Finite element modeling of residual stress profile patterns in hard turning

2009 ◽  
Vol 24 (S1) ◽  
pp. S22-S25
Author(s):  
Y. B. Guo ◽  
S. Anurag
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Hard Turning ◽  
Internal State ◽  
Stress Profile ◽  
Surface Residual Stress ◽  
Mechanical Coupling ◽  
Element Modeling ◽  
Stress Profiles

Hard turning, i.e., turning hardened steels, may produce the unique “hook” shaped residual stress (RS) profile characterized by surface compressive RS and subsurface maximum compressive RS. However, the formation mechanism of the unique RS profile is not yet known. In this study, a novel hybrid finite element modeling approach based on thermal-mechanical coupling and internal state variable plasticity model has been developed to predict the unique RS profile patterns by hard turning AISI 52100 steel (62 HRc). The most important controlling factor for the unique characteristics of residual stress profiles has been identified. The transition of maximum residual stress at the surface to the subsurface has been recovered by controlling the plowed depth. The predicted characteristics of residual stress profiles favorably agree with the measured ones. In addition, friction coefficient only affects the magnitude of surface residual stress but not the basic shape of residual stress profiles.

Contact Stresses in Dovetail Attachments: Finite Element Modeling

1999 ◽  
Author(s):  
G. B. Sinclair ◽  
N. G. Comier ◽  
J. H. Griffin ◽  
G. Meda
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Stress Analysis ◽  
High Stress ◽  
Contact Stresses ◽  
Computational Effort ◽  
Element Analysis ◽  
Element Modeling ◽  
Stress Gradients

The stress analysis of dovetail attachments presents some challenges. These challenges stem from the high stress gradients near the edges of contact and from the nonlinearities attending conforming contact with friction. To meet these challenges with a finite element analysis, refined grids are needed with mesh sizes near the edges of contact of the order of one percent of the local radii of curvature there. A submodeling procedure is described which can provide grids of sufficient resolution in return for moderate computational effort. This procedure furnishes peak stresses near contact edges which are converging on a sequence of three submodel grids, and which typically do converge to within about five percent.

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