Optimization of the Closure-Weld Region of Cylindrical Containers for Long-Term Corrosion Resistance Using the Successive Heuristic Quadratic Approximation Technique*

2003 ◽  
Vol 125 (3) ◽  
pp. 533-539 ◽  
Author(s):  
Zekai Ceylan ◽  
Mohamed B. Trabia
Keyword(s):  
Finite Element ◽  
Random Search ◽  
Nonlinear Problems ◽  
Search Space ◽  
Induction Coil ◽  
Quadratic Approximation ◽  
Approximation Technique ◽  
General Corrosion ◽  
Highly Nonlinear

Welded cylindrical containers are susceptible to stress corrosion cracking (SCC) in the closure-weld area. An induction coil heating technique may be used to relieve the residual stresses in the closure-weld. This technique involves localized heating of the material by the surrounding coils. The material is then cooled to room temperature by quenching. A two-dimensional axisymmetric finite element model is developed to study the effects of induction coil heating and subsequent quenching. The finite element results are validated through an experimental test. The container design is tuned to maximize the compressive stress from the outer surface to a depth that is equal to the long-term general corrosion rate of the container material multiplied by the desired container lifetime. The problem is subject to several geometrical and stress constraints. Two different solution methods are implemented for this purpose. First, an off-the-shelf optimization software is used. The results however were unsatisfactory because of the highly nonlinear nature of the problem. The paper proposes a novel alternative: the Successive Heuristic Quadratic Approximation (SHQA) technique. This algorithm combines successive quadratic approximation with an adaptive random search within varying search space. SHQA promises to be a suitable search method for computationally intensive, highly nonlinear problems.

Optimization of the Closure-Weld Region of Cylindrical Containers for Long-Term Corrosion Resistance

2001 ◽  
Author(s):  
Zekai Ceylan ◽  
Mohamed B. Trabia
Keyword(s):  
Finite Element ◽  
Random Search ◽  
Element Model ◽  
Stress Constraints ◽  
Induction Coil ◽  
Quadratic Approximation ◽  
General Corrosion ◽  
Highly Nonlinear ◽  
Weld Area

Abstract Welded cylindrical containers usually experience stress corrosion cracking (SCC) in the closure-weld area. Induction coil heating technique may be used to relieve the residual stresses from the closure-weld. This technique involves localized heating of the material by the surrounding coils. The material is then cooled to the room temperature by quenching. A two-dimensional axisymmetric finite element model is developed to study the effects of induction coil heating and subsequent quenching. The finite element results are validated through an experimental test. The parameters of the design are tuned to maximize the compressive stress within a layer of thickness from the outer surface that is equal to the long-term general corrosion of Alloy 22 (Appendix A). The problem is subject to geometrical and stress constraints. Two different solution methods are implemented for this purpose. First, an off-the-shelf optimization software is used to obtain an optimum solution. These results are not satisfactory because of the highly nonlinear nature of the problem. The paper proposes a novel alternative: the Successive Heuristic Quadratic Approximation (SHQA) technique. This algorithm combines successive quadratic approximation with an adaptive random search. Examples and discussion are included.

A Consistent Implicit Formulation for Nonlinear Finite Element Modeling With Contact and Friction: Part I—Theory

1991 ◽  
Vol 58 (2) ◽  
pp. 499-506 ◽  
Author(s):  
M. J. Saran ◽  
R. H. Wagoner
Keyword(s):  
Finite Element ◽  
Nonlinear Problems ◽  
Material Model ◽  
Test Problems ◽  
Large Strains ◽  
Numerical Verification ◽  
Viscoplastic Material ◽  
Highly Nonlinear ◽  
Complex Boundary ◽  
Consistent Tangent Operator

A formulation for finite element simulation of highly nonlinear problems including friction and contact with arbitrarily shaped rigid surfaces is proposed (CFS approach), prompted by difficulties in robust and accurate simulations of industrial forming processes. Nonlinearities are caused by large strains, plastic flow, and complex boundary conditions with frictional contact. In Part I the theoretical basis is described and the appropriate numerical algorithm is derived. The complete set of the governing relations, comprising equilibrium and interfacial equations, is appropriately linearized; resulting in a consistent tangent operator of the Newton-Raphson algorithm. In Part II, as a numerical verification, plane-strain sheet-forming processes are analyzed using a rigid-viscoplastic material model. Results are presented and discussed for test problems and for complex simulation of reverse drawing by concave tools.

Nonlinear Long-Term Analysis of Timber-Concrete Composite Structures with Finite Element-Finite Difference Scheme

2014 ◽  
Vol 553 ◽  
pp. 618-624 ◽  
Author(s):  
Nima Khorsandnia ◽  
Hamid R. Valipour ◽  
Keith Crews
Keyword(s):  
Finite Element ◽  
Finite Difference ◽  
Differential Equations ◽  
Composite Structures ◽  
Sufficient Accuracy ◽  
Highly Nonlinear ◽  
Time Dependent Behaviour ◽  
Dependent Behaviour ◽  
Term Analysis

Long-term analysis of timber-concrete composite (TCC) structures is a challenging task owing to the time-dependent behaviour of timber, concrete and connections which are highly nonlinear under variable environmental conditions (i.e. temperature, humidity). In this paper an efficient numerical method that takes advantage of a finite element-finite difference (FE-FD) scheme is presented. The differential equations governing the long-term behaviour of TCC section under variable humidity are solved using the FD scheme and the differential equations governing the mechanical behaviour of the composite beam are solved by a FE formulation recast in the framework of force-interpolation concept. The comparison between experimental data and numerical results shows the sufficient accuracy of the proposed FE-FD model for capturing long-term behaviour of TCC members.

Shock Optimization in a Military Vehicle With Internal Space Frame

2009 ◽  
Author(s):  
Jagadeep Thota ◽  
Mohamed B. Trabia ◽  
Brendan J. O’Toole
Keyword(s):  
Structural Integrity ◽  
Impact Load ◽  
Random Search ◽  
Search Space ◽  
Quadratic Approximation ◽  
Internal Space ◽  
Space Frame ◽  
Military Vehicles ◽  
Space Frames ◽  
Mine Blasts

Space frames are usually used to enhance structural strength of the vehicle while reducing its overall mass. These frames are comprised of beams that are joined together. Recently, space frames are being incorporated in military vehicles. Space frames in military vehicles are however subjected to different types of loading than what is encountered in civilian vehicles such as projectile impacts and land mine blasts. Due to the need to replace a damaged section of the space frame quickly, the proposed space frame is composed of hollow square cross-section bars and angle sections that are bolted together. The space frame is enclosed by uniform-thickness armor, except at the turret. The vehicle is subjected to high impact load to simulate a projectile hit. The objective of this work is to minimize shocks at various critical locations of the space frame while maintaining the overall structural integrity of the vehicle. The vehicle model is parameterized to achieve this objective. This problem is solved using the Successive Heuristic Quadratic Approximation (SHQA) technique, which combines successive quadratic approximation with an adaptive random search within varying search space. The entire optimization process is carried out within MATLAB environment.

Post-Buckling Analysis of Axially Functionally Graded Three-Dimensional Beams

2015 ◽  
Vol 07 (03) ◽  
pp. 1550047 ◽  
Author(s):  
Şeref Doğuşcan Akbaş
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Nonlinear Problems ◽  
Element Model ◽  
Buckling Analysis ◽  
Functionally Graded ◽  
Highly Nonlinear ◽  
Lagrangian Finite Element ◽  
Post Buckling

Post-buckling analysis of an axially functionally graded (AFG) cantilever beam subjected to an axial nonfollower compression load is studied in this paper by using the total Lagrangian finite element model of three-dimensional continuum approximations. Material properties of the beam change in the axial direction according to a power-law function. In this study, finite element model of the beam is constructed by using total Lagrangian finite element model of three-dimensional continuum for an eight-node quadratic element. It is known that post-buckling problems are geometrically nonlinear problems. The considered highly nonlinear problem is solved by using incremental displacement-based finite element method in conjunction with Newton–Raphson iteration method. There is no restriction on the magnitudes of deflections and rotations in contradistinction to von-Karman strain displacement relations. The obtained results are compared with the published results. In this study, the effects of the material distribution on the post-buckling response of the AFG beam are investigated in detail. The differences between of material distributions are investigated in the post-buckling analysis. Numerical results show that the above-mentioned effects play a very important role on the post-buckling responses of the beam, and it is believed that new results are presented for post-buckling of AFG beams which are of interest to the scientific and engineering community in the area of FGM structures.

Finite Element Analysis of the Rubber of the Prosthetic Knee Joint

2014 ◽  
Vol 607 ◽  
pp. 346-349
Author(s):  
Ying Liu ◽  
Xiu Feng Zhang ◽  
Yan Ma
Keyword(s):  
Finite Element ◽  
Nonlinear Problems ◽  
Element Model ◽  
Element Analysis ◽  
Rubber Material ◽  
Knee Motion ◽  
Prosthetic Knee ◽  
Rubber Bearing ◽  
Highly Nonlinear ◽  
Selection Of

Rubber played a buffer role in prosthetic knee motion. Rubber bearing is a very complicated process, and rubber material itself is nonlinear. ABAQUS software can able to deal with highly nonlinear problems. Input rubber test data in ABAQUS, selection of constitutive model, and then the finite element model is established, which is calculated, finally obtains compression under different loads.

scholarly journals Finite element estimates for a class of nonlinear variational inequalities

1993 ◽  
Vol 16 (3) ◽  
pp. 503-509 ◽  
Author(s):  
Muhammad Aslam Noor
Keyword(s):  
Applied Sciences ◽  
Finite Element ◽  
Approximate Solution ◽  
Variational Inequalities ◽  
Error Estimates ◽  
Obstacle Problem ◽  
Nonlinear Problems ◽  
Highly Nonlinear ◽  
Unilateral Problems ◽  
Special Case

It is well known that a wide class of obstacle and unilateral problems arising in pure and applied sciences can be studied in a general and unifield framework of variational inequalities. In this paper, we derive the error estimates for the finite element approximate solution for a class of highly nonlinear variational inequalities encountered in the field of elasticity and glaciology in terms ofW1,p(Ω)andLp(Ω)-norms. As a special case, we obtain the well-known error estimates for the corresponding linear obstacle problem and nonlinear problems.

Optimization of a Military Vehicle Space Frame Subject to High Impact Loading

2008 ◽  
Author(s):  
Jagadeep Thota ◽  
Mohamed B. Trabia ◽  
Brendan J. O’Toole
Keyword(s):  
Structural Integrity ◽  
Impact Load ◽  
Random Search ◽  
Element Model ◽  
Search Space ◽  
High Impact ◽  
Quadratic Approximation ◽  
Space Frame ◽  
Cross Sectional ◽  
Space Frames

Space frames are usually used to enhance structural strength of the vehicle while reducing its overall weight. These frames are comprised of beams connected together at joints. Recently, space frames are incorporated in military vehicles. However, space frames in this case are subjected to different types of loading than what is encountered in civilian vehicles such as, projectile and land mine attacks. In this paper, a finite element model for the upper half of the space frame of an armored vehicle is developed. The space frame is composed of hollow square cross-section bars and angle sections and is enclosed by uniform-thickness armor, except at the turret. The vehicle is subjected to high impact load that simulates an impact of a projectile. The model is parameterized to minimize the mass of the space frame and vehicle armor by varying the cross-sectional parameters of the beam members and joints, and the thickness of the armor plate, while maintaining the overall structural integrity of the space frame. This problem is solved using the Successive Heuristic Quadratic Approximation (SHQA). This algorithm combines successive quadratic approximation with an adaptive random search within varying search space. The entire optimization process is carried out within MATLAB environment. Results show significant reduction of the mass of the vehicle.

scholarly journals Enhancement in Thermal Energy and Solute Particles Using Hybrid Nanoparticles by Engaging Activation Energy and Chemical Reaction over a Parabolic Surface via Finite Element Approach

2021 ◽  
Vol 5 (3) ◽  
pp. 119
Author(s):  
Yu-Ming Chu ◽  
Umar Nazir ◽  
Muhammad Sohail ◽  
Mahmoud M. Selim ◽  
Jung-Rye Lee
Keyword(s):  
Finite Element ◽  
Nonlinear Problems ◽  
Surface Flow ◽  
Hybrid Nanoparticles ◽  
Surface Drag ◽  
Independent Analysis ◽  
Highly Nonlinear ◽  
Finite Element Procedure ◽  
Element Approach ◽  
Industrial Use

Several mechanisms in industrial use have significant applications in thermal transportation. The inclusion of hybrid nanoparticles in different mixtures has been studied extensively by researchers due to their wide applications. This report discusses the flow of Powell–Eyring fluid mixed with hybrid nanoparticles over a melting parabolic stretched surface. Flow rheology expressions have been derived under boundary layer theory. Afterwards, similarity transformation has been applied to convert PDEs into associated ODEs. These transformed ODEs have been solved the using finite element procedure (FEP) in the symbolic computational package MAPLE 18.0. The applicability and effectiveness of FEM are presented by addressing grid independent analysis. The reliability of FEM is presented by computing the surface drag force and heat transportation coefficient. The used methodology is highly effective and it can be easily implemented in MAPLE 18.0 for other highly nonlinear problems. It is observed that the thermal profile varies directly with the magnetic parameter, and the opposite trend is recorded for the Prandtl number.

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