A Whole Ship Finite Element Analysis With the Input of Nonlinear Wave Loads in the Irregular and Multi-Directional Waves

Author(s):  
Yoshitaka Ogawa ◽  
Masayoshi Oka

Authors developed a whole ship finite element analysis system from a nonlinear wave loads to a structural strength at real sea state. A methodology for the rational analysis of structural strength is examined. Firstly, wave pressure, which is the input for the present whole ship finite element analysis and has much effect on the accuracy of a whole ship analysis, is validated through the comparison with experiments. It is confirmed that the present computation can estimates wave pressure in various wave condition accurately. Secondly, the whole ship finite element analysis system by the combination with the computation of nonlinear wave pressure is verified. It is verified that the present method can evaluate a structural response in irregular waves with taking account of the nonlinear effect of ship motions and slamming induced impact loads explicitly. Finally, through the structural analysis in various ship forward speed and wave condition by means of the present computation, the importance to assess a structural strength taking account of the effect of operational condition is clarified.

2014 ◽  
Vol 945-949 ◽  
pp. 1143-1149
Author(s):  
Hai Xia Sun ◽  
Hua Kai Wei ◽  
Xiao Fang Zhao ◽  
Jia Rui Qi

The finite element model of the concrete mixing truck’s frame is builded by using shell as basic element, and the process of building the finite element model of the balance suspension is introduced in detail. Based on this, frame’s stress on five types of typical operating conditions are calculated by using the finite element analysis software, NASTRAN, and results can show the dangerous position and the maximum stress position on the frame. The analysis result on structural strength can provide the basis for further improving the frame structure.


2015 ◽  
Vol 723 ◽  
pp. 96-99
Author(s):  
Xiao Wei Wang ◽  
Mao Xiang Lang

The vice frame bears and transfers the forces and loads between the bogie and the vehicle body.The strength of the vice frame relates directly to the stability and smoothness of the vehicle. In this study, finite element analysis is utilized first to analyse the structural strength and fatigue life of the vice frame, and the recognize the weak parts of its structure in order to enhance its structural strength in the following design work.The finite element analysis is performed on a simulation software Ansys. Then an experiment is designed to test the fatigue strength of the vice frame. The experimental result indicates that the fatigue strength of the object corresponds to the standards and the finite element analysis has high feasibility in solving this kind of problem.


2013 ◽  
Vol 288 ◽  
pp. 228-232
Author(s):  
Ye Fei ◽  
Yan Jun Liu ◽  
Yuan Yuan Li

In this paper, by defining and associating the boom structure parameter characteristic of truck crane, we build a parameterized automatic analysis system of truck crane boom, based on the VB platform with the ANSYS APDL language. In the system, the basic parameters of the crane structural finite element analysis can be obtained by human-computer exchange, achieving the finite element automatic modeling and analysis of boom structure under the driving of the parameters. Engineering examples show that the system is reliable and accurate results.


Author(s):  
Gokul Raj P. ◽  
Balasubramanian Esakki ◽  
Surendar Ganesan

Unmanned Aerial Vehicles are extensively exploited for diverse applications importantly surveillance, defence and military, photography. Development of unmanned amphibious vehicle with integrating features of hovercraft principles and multirotor to navigate along and above the water surface, land surface and flying in the air is challenging demand. This article presents conceptual design of amphibious vehicle for the payload capacity of 7 kg with an endurance of 20 minutes and provision for mounting water sampler to collect water samples in remote water bodies. Structural strength characteristics of each part of the amphibious vehicle and integrity of same are analysed by Finite Element Analysis. FEA results indicated that the designed amphibious vehicle structure is well within the stress limit and minimal displacement is obtained. Based on structural analysis materials for various parts of the amphibious vehicle are determined and integrated structure is analysed.


Author(s):  
Kaworu Yodo ◽  
Hiroshi Kawai ◽  
Hiroshi Okada ◽  
Masao Ogino ◽  
Ryuji Shioya

Fracture mechanics analysis using the finite element method has been one of the key methodologies to evaluate structural integrity for aging infrastructures such as aircraft, ship, power plants, etc. However, three-dimensional crack analyses for structures with highly complex three-dimensional shapes have not widely been used, because of many technical difficulties such as the lack of enough computational power. The authors have been developing a fracture mechanics analysis system that can deal with arbitrary shaped cracks in three-dimensional structures. The system consists of mesh generation software, a finite element analysis program and a fracture mechanics module. In our system, a Virtual Crack Closure-Integral Method (VCCM) for the quadratic tetrahedral finite elements is adopted to evaluate the stress intensity factors. This system can perform the three-dimensional fracture analyses. Fatigue and SCC crack propagation analyses with more than one cracks of arbitrary complicated shapes and orientations. The rate and direction of crack propagation are predicted by using appropriate formulae based on the stress intensity factors. When the fracture mechanics analysis system is applied to the complex shaped aging structures with the cracks which are modeled explicitly, the size of finite element analysis tends to be very large. Therefore, a large scale parallel structural analysis code is required. We also have been developing an open-source CAE system, ADVENTURE. It is based on the hierarchical domain decomposition method (HDDM) with the balancing domain decomposition (BDD) pre-conditioner. A general-purpose parallel structural analysis solver, ADVENTURE_Solid is one of the solver modules of the ADVENTURE system. In this paper, we combined VCCM for the tetrahedral finite element with ADVENTURE system and large-scale fracture analyses are fully automated. They are performed using the massively parallel super computer ES2 (Earth Simulator 2) which is owned and run by JAMSTEC (Japan Agency for Marine-Earth Science and Technology).


Author(s):  
Tom Trias ◽  
Myo Kyaw ◽  
Darren Thompson ◽  
Laurence Leff ◽  
Z. Malik

Abstract We have written two pieces of software that are necessary for mechanical engineering design and analysis. These are a CAD-CAM system using Constructive Solid Geometry and a finite element analysis system. Both are unique in that they are written in the symbolic math system MAPLE. All entities in each of these programs are entered symbolically. For example, in the CSG system, we talk about a square whose dimensions are a, b and side1. In the finite element analysis, we talk about a symbolic representation for a regular grid. This scheme has advantages over conventional finite element analysis and Constructive Solid Geometry approaches.


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