Slam Induced Loads on a 3D Bow With Various Pitch Angles

2016 ◽  
Author(s):  
Yiwen Wang ◽  
Weiguo Wu ◽  
C. Guedes Soares
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Impact Velocity ◽  
Pitch Angle ◽  
Water Entry ◽  
Experimental Measurements ◽  
Numerical Predictions ◽  
Element Method

A 3D water entry of a typical bow model of sea-river link ship is studied using both experimental measurements and numerical predictions. A large number of systematic experiments have been performed with different pitch angles. The slamming process is simulated through finite element method with LS-DYNA. The distribution and magnitude of slam induced loads is determined from experiments and is calculated. The effect of the pitch angle and impact velocity is discussed based on the comparison between the predicted results and the experiments values.

Slam induced loads on a 3D bow with various pitch angles

2019 ◽  
pp. 1-18 ◽  
Author(s):  
Yiwen Wang ◽  
Weiguo Wu ◽  
Shan Wang ◽  
Carlos Guedes Soares
Keyword(s):  
Impact Velocity ◽  
Pitch Angle ◽  
Water Entry ◽  
Model Tests ◽  
Experimental Measurements ◽  
Pressure Distributions ◽  
Slamming Load

Abstract A 3D water entry of a typical bow model of River-to-Sea ship is studied experimentally. A large number of systematic experiments have been performed for the bow model with different pitch angles. Considering various pitch angles and impact velocities in the model tests, the slamming pressure distributions on the bottom of the bow are presented and discussed. The measured slamming pressures on the bow are identified in terms of the maximum slamming coefficient. The effects of the pitch angle and impact velocity on slamming pressure are discussed as well, based on the experimental measurements. It is shown that the slamming load on the bottom of the model increases as the pitch angle decreases in most cases. With a higher impact velocity, the coefficient of the maximum slamming pressure is smaller for most of the tested cases.

Analysis and Optimization of Metal to Composite Joints for Marine Structures

2014 ◽  
Vol 556-562 ◽  
pp. 91-95
Author(s):  
Xiao Wen Li ◽  
Ping Li ◽  
Zhuang Lin ◽  
Dong Mei Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mechanical Performance ◽  
Optimization Method ◽  
Additional Stress ◽  
Marine Structures ◽  
Hybrid Joint ◽  
Composite Joint ◽  
Numerical Predictions ◽  
Element Method

Composite to metal joints as important components of marine structures are gradually found in the marine industry. The purpose of this study is to investigate mechanical performance and optimization method of the composite sandwich to steel joints. The main emphasis was placed on the mechanical properties of a hybrid joint between a sandwich glass fibre reinforced plastic superstructure and a steel main hull. Based on the experiments of a base joint, a new finite element method was used to analyze a series of joints. The optimized joint was presented due to reducing weight and enhancing the mechanical performance. The numerical predictions of the base hybrid joint showed a very good correlation with the experiment results, which validated the reliability of the new finite element method. The strength of the optimized joint was also evaluated by finite element method. The result is similar to the base joint. And there is no additional stress concentration in weak parts. The optimized joint has 30% lower weight than the base joint, and the stress is only about 5% ~ 56% of the base one. The results of the present work imply that the change of geometric parameter is an effective method to improve the performance of the metal to composite joint.

Numerical Solution of Multidimensional Compressible Flow by High Order Nodal Discontinuous Galerkin Method

2013 ◽  
Vol 392 ◽  
pp. 100-104 ◽  
Author(s):  
Fareed Ahmed ◽  
Faheem Ahmed ◽  
Yong Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Solution ◽  
Finite Volume Method ◽  
Discontinuous Galerkin ◽  
Finite Volume ◽  
High Order ◽  
Numerical Predictions ◽  
Volume Method ◽  
Element Method

In this paper we present a robust, high order method for numerical solution of multidimensional compressible inviscid flow equations. Our scheme is based on Nodal Discontinuous Galerkin Finite Element Method (NDG-FEM). This method utilizes the favorable features of Finite Volume Method (FVM) and Finite Element Method (FEM). In this method, space discretization is carried out by finite element discontinuous approximations. The resulting semi discrete differential equations were solved using explicit Runge-Kutta (ERK) method. In order to compute fluxes at element interfaces, we have used Roe Approximate scheme. In this article, we demonstrate the use of exponential filter to remove Gibbs oscillations near the shock waves. Numerical predictions for two dimensional compressible fluid flows are presented here. The solution was obtained with overall order of accuracy of 3. The numerical results obtained are compared with experimental and finite volume method results.

Numerical Solution of the Incompressible Boundary-Layer Equations Using the Finite Element Method

1992 ◽  
Vol 114 (4) ◽  
pp. 504-511 ◽  
Author(s):  
J. A. Schetz ◽  
E. Hytopoulos ◽  
M. Gunzburger
Keyword(s):  
Boundary Layer ◽  
Finite Element Method ◽  
Finite Element ◽  
Memory Storage ◽  
The Finite Element Method ◽  
Boundary Layer Equations ◽  
Numerical Predictions ◽  
Incompressible Boundary Layer ◽  
Incompressible Boundary ◽  
Element Method

A new approach to the solution of the two-dimensional, incompressible, boundary-layer equations based on the Finite Element Method in both directions is investigated. Earlier Finite Element Method treatments of parabolic boundary-layer problems used finite differences in the streamwise direction, thus sacrificing some of the possible advantages of the Finite Element Method. The accuracy and computational efficiency of different interpolation functions for the velocity field are evaluated. A new element especially designed for boundary layer flows is introduced. The effect that the treatment of the continuity equation has on the stability and accuracy of the numerical results is also discussed. The parabolic nature of the equations is exploited in order to reduce the memory requirements. The solution is obtained for one line at a time, thus only two levels are required to be stored at any time. Efficient solvers for tridiagonal and pentadiagonal forms are used for solving the resulting matrix problem. Numerical predictions are compared to analytical and experimental results for laminar and turbulent flows, with and without pressure gradients. The comparisons show very good agreement. Although most of the cases were tested on a mainframe, the low requirements in CPU time and memory storage allows the implementation of the method on a conventional PC.

Steady-state multiphysics analysis of stator bar using finite element method

2020 ◽  
pp. 1-14
Author(s):  
José William Ribeiro Borges ◽  
Wellington da Silva Fonseca ◽  
Fernando de Souza Brasil ◽  
Ramon C.F. Araújo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Steady State ◽  
Thermal Effects ◽  
Experimental Measurements ◽  
The Finite Element Method ◽  
Insulation System ◽  
State Behavior ◽  
Steady State Behavior ◽  
Element Method

The electrical insulation is one of the main sources of failures in hydro-generators, therefore it is important to research the insulation system of stator bars. In this paper, it is developed a steady-state multiphysics analysis of a stator bar using the Finite Element Method to assess its steady-state behavior in the electrical, magnetic and thermal domains. Different aspects are analyzed in simulations, such as capacitance, mechanical stress and thermal effects. Numerical results are compared with experimental measurements for validation.

A Localized Finite-Element Method for the Nonlinear Steady Waves Due to a Two-Dimensional Hydrofoil

1994 ◽  
Vol 38 (01) ◽  
pp. 42-51
Author(s):  
Kwang June Bai ◽  
Jae Hoon Han
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Free Surface ◽  
Computational Method ◽  
Experimental Measurements ◽  
Surface Boundary ◽  
Two Dimensional ◽  
True Solution ◽  
Nonlinear Free Surface ◽  
Element Method

An application is described of the localized finite-element method to a steady nonlinear free-surface flow past a submerged two-dimensional hydrofoil at an arbitrary angle of attack. The earlier investigations with the linear free-surface boundary condition have shown some disagreement between the computed results and the experimental measurements for the cases of shallow submergence. The aim of this paper is to investigate the effect of the nonlinear free-surface condition for the cases where the linear results show disagreement with the experimental measurements. The computational method of solution is the localized finite-element method based on the classical Hamilton's principle. In the present study, a notable step is introduced in the matching procedure between the fully nonlinear and the linear subdomains. The numerical results of wave resistance, lift force, and circulation strength are presented. The computed pressure distributions on the hydrofoil and wave profiles are shown and compared with the experimental measurements and also with the linear computational results. The present computed results show better agreement with the experimental results. In some cases, however, a difficulty in the convergence of the iterative solution procedure was experienced. This difficulty in the convergence may be due to the limit of the range of the existence of the true solution in potential-flow formulation.

scholarly journals Study of Metallic Housing of the Adder Gearbox to Reduce the Noise and to Improve the Design Solution

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 912
Author(s):  
Nicoleta Gillich ◽  
Nicolae Sîrbu ◽  
Sorin Vlase ◽  
Marin Marin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Modal Analysis ◽  
Design Solution ◽  
Experimental Measurements ◽  
The Finite Element Method ◽  
Lower Weight ◽  
Metal Construction ◽  
Element Method

In the manufacture of commercial trucks, used in oil installations or the army, two identical engines are used on a single chassis, whose power is summed by a gearbox, a compact metal construction, which must meet multiple operating requirements. The paper studies the behavior of such an adding box, currently used in manufacturing, and an improved, welded solution that produces less noise and has a lower weight. The finite element method is used for modeling the gearbox in order to analyze stresses and strains and obtain a modal analysis of the system. The results obtained from the calculation are then verified by experimental measurements. The two versions are analyzed in parallel to highlight the advantages of the second version.

A finite element solution technique for the Boltzmann equation

1970 ◽  
Vol 42 (1) ◽  
pp. 177-191 ◽  
Author(s):  
T. Taz Bramlette ◽  
Robert H. Mallett
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boltzmann Equation ◽  
Finite Elements ◽  
Solution Technique ◽  
Algebraic Models ◽  
Numerical Predictions ◽  
The Boltzmann Equation ◽  
Viscous Shear ◽  
Element Method

A new method is presented for solution of the Boltzmann equation governing the dynamic behaviour of gases. The essence of the method is idealization of the problem domain into subdomains called finite elements. Then, the Galerkin assumed-mode technique is employed as the basis for discretization of the individual finite elements and also for the assembly of the resulting algebraic models for these finite elements to form an algebraic model for the complete problem. The procedure is cast in a systematic matrix notation that makes evident the broad application potential of the analysis method. An illustrative application is presented for the problem of one-dimensional, linearized Couette flow. Numerical predictions of macroscopic flow velocity and viscous shear stress based upon the subject finite element method are compared with alternative analytical and numerical results. Special attributes of the finite element method are discussed in the context of this example problem. Applications to practical problems governed by generalized forms of the Boltzmann equation are projected on the basis of concepts established herein.

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