Influence of Transverse Cracks on Ultimate Strength of a Steel Plate Under Compression

Author(s):  
Abbas Bayatfar ◽  
Jerome Matagne ◽  
Philippe Rigo

This study has been carried out on ultimate compressive strength of a cracked steel plate component, considering the effects of initial imperfections (transverse and longitudinal residual stresses and initial deflection, as well). The main objective of this paper is to numerically investigate the influence of crack location and crack length on ultimate strength of a steel plate under monotonic longitudinal compression. This investigation is performed through non-linear finite element (FE) analysis using ANSYS commercial finite element code in which is employed Newton-Raphson method. The FE results indicate that the length of transverse crack and especially its location can significantly affect the magnitude of ultimate strength where the steel plate is subjected to longitudinal compressive action.

Author(s):  
D Chichì ◽  
Y Garbatov

The objective of the present study is to investigate the possibility to recover the ultimate strength of a rectangular steel plate with a manhole shape opening subjected to a uniaxial compressive load and non-uniform corrosion degradation reinforced by additional stiffeners. Finite element analyses have been carried out to verify the possible design solutions. A total of four finite element models are generated, including 63 sub-structured models. The non-uniform corrosion has been generated by the Monte Carlo simulation. The reinforcement process covers three scenarios that include mounting of two longitudinal stiffeners, two longitudinal and two transverse stiffeners and the flange on the opening. The positioning of the stiffeners has also been studied. A total of 10 cases has been selected and tested for the numerical experiment. Three different assessments have been performed to evaluate the ultimate strength, weight and cost. Two additional studies on the effect of the plate thickness and slenderness have been also carried out.


2011 ◽  
Vol 328-330 ◽  
pp. 1436-1439
Author(s):  
Shu Ni Song ◽  
Jing Yi Liu

Newton-Raphson (N-R) method has been employed to solve the system of simultaneous equations arising in Rigid-Plastic finite element simulation. The combination of the improved rotative mid-point mensuration and the N-R method, named the M-P method is designated to solve the equations of velocity increment in Rigid-Plastic FEM. The CPU times required for calculation by the M-P method and the N-R method are compared and it is found that the CPU time required for calculation of the N-R method is more than the M-P method. The calculated rolling forces by the M-P method and the N-R method are compared and it is found that the former correlates better with the measured value. Numerical tests and application show that the M-P method is feasible and steady.


2018 ◽  
Vol 177 ◽  
pp. 01007
Author(s):  
Muhammad Alie Zubair Muis ◽  
Obednego Icon Yan Franchover ◽  
Baeda Achmad Yasir ◽  
Taufiqur Rachman ◽  
Juswan

The brace configuration plays an important role to the ultimate strength of fixed jacket platform. The braces against the combined load in vertical and horizontal direction. In the present study, the ultimate strength of the fixed jacket platform is analysed considering the shape of the structural geometric. Four types of brace configuration namely, K, N, X and Y are taken to be assessed. Dimensions of the structure are constant including properties and materials. The boundary conditions are assumed to be fixed at the bottom part. The Non-Linear Finite Element Analysis (NLFEA) is adopted to calculate the ultimate strength of the structure and those results of brace configuration are compared with one another and discussed in the present study.


2015 ◽  
Vol 3 (4) ◽  
Author(s):  
Dongdong Zhang ◽  
Douglas E. Smith

This paper presents a computational approach for simulating the motion of nanofibers during fiber-filled composites processing. A finite element-based Brownian dynamics simulation (BDS) is proposed to solve for the motion of nanofibers suspended within a viscous fluid. We employ a Langevin approach to account for both hydrodynamic and Brownian effects. The finite element method (FEM) is used to compute the hydrodynamic force and torque exerted from the surrounding fluid. The Brownian force and torque are regarded as the random thermal disturbing effects which are modeled as a Gaussian process. Our approach seeks solutions using an iterative Newton–Raphson method for a fiber's linear and angular velocities such that the net forces and torques, including both hydrodynamic and Brownian effects, acting on the fiber are zero. In the Newton–Raphson method, the analytical Jacobian matrix is derived from our finite element model. Fiber motion is then computed with a Runge–Kutta method to update fiber position and orientation as a function of time. Instead of remeshing the fluid domain as a fiber migrates, the essential boundary condition is transformed on the boundary of the fluid domain, so the tedious process of updating the stiffness matrix of finite element model is avoided. Since the Brownian disturbance from the surrounding fluid molecules is a stochastic process, Monte Carlo simulation is used to evaluate a large quantity of motions of a single fiber associated with different random Brownian forces and torques. The final fiber motion is obtained by averaging numerous fiber motion paths. Examples of fiber motions with various Péclet numbers are presented in this paper. The proposed computational methodology may be used to gain insight on how to control fiber orientation in micro- and nanopolymer composite suspensions in order to obtain the best engineered products.


1993 ◽  
Vol 60 (3) ◽  
pp. 575-582 ◽  
Author(s):  
C. H. Jenkins ◽  
J. W. Leonard

Problems associated with viscoelastic membrane structures have been documented, e.g., dynamic wrinkling and its effects on fatigue analysis and on snap loading. In the proposed analysis method, the constitutive equation is approximated by a finite difference equation and embedded within a nonlinear finite element spatial discretization. Implicit temporal integration and a modified Newton-Raphson method are used within a time increment. The stress-strain hereditary relation is formally derived from thermodynamic considerations. Use of modified strain-energy and dissipation functions facilitates the description of wrinkling during the analysis. Applications are demonstrated on an inflated cylindrical cantilever and on a submerged cylindrical membrane excited by waves.


1998 ◽  
Vol 33 (5) ◽  
pp. 385-394 ◽  
Author(s):  
C T Kang ◽  
D G Moffat ◽  
J Mistry

The effects of chord axial compression on the ultimate strength of a double-tee (DT) tubular joint subjected to brace out-of-plane bending have been studied both experimentally and numerically. The results from four experimental tests with different levels of chord compression are presented, together with the results of a parametric study using non-linear finite element procedures. The results are compared with the American Petroleum Institute's design rules for DT joints subjected to combined brace and chord loading.


Author(s):  
Dongdong Zhang ◽  
Douglas E. Smith

This paper presents a computational approach for simulating the motion of nano-fibers during polymer nano-composites processing. A finite element-based Brownian dynamics simulation is proposed to solve the motion of nano-fibers suspended within a viscous fluid. In this paper, a Langevin approach is used to account for both hydrodynamic and Brownian effects. We develop a stand-alone Finite Element Method (FEM) for modeling the hydrodynamic effect exerted from the surrounding fluid. The Brownian effects are regarded as the random thermal disturbing forces/torques, which are modeled as a Gaussian process. Our approach seeks solutions using an iterative Newton-Raphson method for the fiber’s linear and angular velocities such that the net forces and torques, i.e. the combination of hydrodynamic and Brownian effects, acting on the fiber are zero. In the Newton-Raphson method, the analytical Jacobian matrix is derived from our finite element model. Fiber motion is then computed with a Runge-Kutta method to update the fiber positions and orientations as a function of time. Instead of re-meshing the fluid domain as fiber moves, we applied the transformed essential boundary conditions on the boundary of fluid domain, so the tedious process of updating stiffness matrix of finite element model is avoided. Since Brownian disturbance from the fluid molecules is a stochastic process, Monte-Carlo simulation is used to evaluate the motion of a great many fibers associated with different random Brownian forces and torques. The final fiber motion is obtained by averaging a numerous fiber motion paths. Examples of fiber motions with various Péclet numbers are presented in this paper. The proposed computational methodology will be used to gain insight on how to control fiber orientations in micro- and nano-polymer composite suspensions in order to obtain the best engineered products.


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