Transient Waves in Anisotropic Laminated Plates, Part 2: Application

1991 ◽  
Vol 113 (2) ◽  
pp. 235-239 ◽  
Author(s):  
G. R. Liu ◽  
J. Tani ◽  
T. Ohyoshi ◽  
K. Watanabe
Keyword(s):  
Numerical Method ◽  
Impact Load ◽  
Three Dimensional ◽  
Point Load ◽  
Laminated Plates ◽  
Impact Loads ◽  
Dimensional Problem ◽  
Transient Waves ◽  
Isotropic Plates ◽  
Hybrid Numerical Method

The application of the hybrid numerical method proposed in the previous paper by the present authors to the computation of transient waves in composite material plates excited by step-impact loads is presented in this paper. Both the two-dimensional problem (line step-impact load) and the three-dimensional problem (point step-impact load) are considered. First, the displacement responses of isotropic plates are computed by using the hybrid numerical method and the results are compared with those obtained by the method of the head of the pulse approximation and the method of generalized rays. Next, the displacement responses of a hybrid composite laminated plate excited by a line step-impact load and a point load are calculated, and some interesting results are obtained.

Transient Waves in Anisotropic Laminated Plates, Part 1: Theory

1991 ◽  
Vol 113 (2) ◽  
pp. 230-234 ◽  
Author(s):  
G. R. Liu ◽  
J. Tani ◽  
T. Ohyoshi ◽  
K. Watanabe
Keyword(s):  
Numerical Method ◽  
Fourier Transforms ◽  
Dynamic Equilibrium ◽  
Virtual Work ◽  
Laminated Plates ◽  
The Finite Element Method ◽  
Equilibrium Equations ◽  
Transient Waves ◽  
Plate Elements ◽  
Hybrid Numerical Method

A hybrid numerical method in which the finite element method and the method of Fourier transforms are combined is proposed for computing the transient waves in anisotropic laminated plates excited by impact loads. The anisotropic laminated plate is divided into N plate elements, and the principle of virtual work is used to develop approximate dynamic equilibrium equations for three- and two-dimensional problems. The displacement response is determined by employing the Fourier transformation and the modal analysis. This hybrid numerical method is straightforward and easy to use.

scholarly journals Efficient 3D Volume Reconstruction from a Point Cloud Using a Phase-Field Method

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Darae Jeong ◽  
Yibao Li ◽  
Heon Ju Lee ◽  
Sang Min Lee ◽  
Junxiang Yang ◽  
...  
Keyword(s):  
Image Segmentation ◽  
Numerical Method ◽  
Phase Field ◽  
Point Cloud ◽  
Three Dimensional ◽  
Field Method ◽  
Phase Field Method ◽  
Volume Reconstruction ◽  
Hybrid Numerical Method ◽  
3D Volume

We propose an explicit hybrid numerical method for the efficient 3D volume reconstruction from unorganized point clouds using a phase-field method. The proposed three-dimensional volume reconstruction algorithm is based on the 3D binary image segmentation method. First, we define a narrow band domain embedding the unorganized point cloud and an edge indicating function. Second, we define a good initial phase-field function which speeds up the computation significantly. Third, we use a recently developed explicit hybrid numerical method for solving the three-dimensional image segmentation model to obtain efficient volume reconstruction from point cloud data. In order to demonstrate the practical applicability of the proposed method, we perform various numerical experiments.

Numerical Method for Multi-Dimensional Freezing Problems in Arbitrary Domains

1978 ◽  
Vol 100 (2) ◽  
pp. 294-299 ◽  
Author(s):  
T. Saitoh
Keyword(s):  
Numerical Method ◽  
Cooling Rate ◽  
Three Dimensional ◽  
Dimensional Problem ◽  
Freezing Front ◽  
One Dimensional ◽  
Arbitrary Geometries ◽  
Independent Variable ◽  
Change Of Variable ◽  
The One

This paper presents a simple numerical method for solving two and three-dimensional freezing problems with arbitrary geometries. The change of variable method introduced by Landau for the one-dimensional problem is extended to the multi-dimensional using an independent variable which takes constant values at the boundary and the freezing front. Example calculations were performed for the Stefan type freezing problem in regular squares, triangles, and ellipses. Then some of the results were compared with the experimental ones that were obtained for the constant cooling rate.

scholarly journals Numerical Investigation of Rising Vapour Bubble in Convective Boiling Using an Advanced 3D Hybrid Numerical Method

2021 ◽  
Author(s):  
Syed Ahsan Sharif ◽  
Mark Kai Ming Ho ◽  
Victoria Timchenko ◽  
Guan Heng Yeoh
Keyword(s):  
Numerical Method ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Phase Flow ◽  
Vapour Bubble ◽  
Convective Boiling ◽  
Hybrid Numerical Method ◽  
New Type ◽  
Multi Phase Flow ◽  
Multi Phase

This chapter introduces an advanced and new type of Three-Dimensional (3D) numerical method called the InterSection Marker (ISM) method. The ISM method - a hybrid Lagrangian–Eulerian 3D front-tracking algorithm specifically crafted for multi-phase flow simulation. The method was used to simulate rising vapour bubble behaviour in Convective boiling conditions. Two applications: bubble growth and bubble condensation due to the convective action, were investigated. Numerically obtained bubble properties, such as size, shape and velocity, are compared well against the past works, and the ISM method proved to be an efficient numerical tool for the interface tracking of multi-phase flow CFD simulations involving heat and mass transfer.

scholarly journals A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

2021 ◽  
Vol 11 (9) ◽  
pp. 4136
Author(s):  
Rosario Pecora
Keyword(s):  
Numerical Method ◽  
Initial Conditions ◽  
Impact Load ◽  
Numerical Models ◽  
Landing Gear ◽  
Design Stage ◽  
Impact Dynamics ◽  
State Variables ◽  
Adopted Model ◽  
The Impact

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

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