Computer-aided Engineering Analysis Research Articles

Cover die service life improvement by biomimetic laser-remelting process and CAE simulation

Die service life improvement is an important problem in high-pressure die-casting industry. As many factors affecting the service life, die service life improvement is a systematic project. In this paper, a cover die-casting die was investigated in order to increase its life time. Different die materials, computer-aided engineering (CAE) analysis, biomimetic laser-remelting process, and die structure optimization are adopted in order to enhance its performance. The die service lives are traced for dies of different die materials (H13 and SKD61). The die service lives are compared for dies with/without structure optimization with the help of CAE simulation. The application shows that CAE simulation is a useful tool for die structure optimization. Experiment result on SKD61 die steel after laser-remelting process shows that biomimetic laser-remelting process provides desirable microstructural and microhardness changes in biomimetic units, which induces the intensified particles for improving the service life.

Automotive Bolts Tightening Analysis using Contact Stress Simulation: Developing An Optimal CAE Design Approach Model

In recent years, enhancing computer-aided engineering (CAE) analysis is the most pressing issue facing companies seeking to implement development design that results in high quality and shortened delivery times. This paper presents an Optimal CAE Design Approach Model that can be used to reform the business processes associated with development design. The model consists of the following steps: (1) defining the problem, (2) conducting prototype testing, (3) visualizing the problem, (4) employing the CAE technological element analysis model, (5) conducting a two-dimensional CAE analysis, (6) conducting a three-dimensional CAE analysis, (7) carrying out a predictive evaluation, (8) optimizing the design, and (9) verifying the results. As a specific application for this process, the authors focused on the ongoing problem of bolt loosening at automakers, using the model to explain the loosening mechanism by analyzing the contact stress at the bearing surfaces in bolted parts and gain new knowledge.

Integration system of the telescopic boom on case-based reasoning

For the purpose of improving the efficiency and quality of design process, case-based reasoning (CBR) technology was applied to the design of the telescopic boom. Firstly, the current design method for the telescopic boom was analysed and the principle of CBR was described. Secondly, according to the characteristics of the telescopic boom, three key technologies of CBR were studied and the corresponding methods were provided, which are the case representation of the boom based on the characteristics of the boom, the case retrieval algorithm of nearest-neighbour matching function according to key characteristics of the boom, and case adaptation strategy combining the manual revision with the programme check. Also, for the purpose of meeting the design demand, computer aided engineering (CAE) method was applied to check the performance of the adapted case. The model of CAE analysis was established based on three-dimensional parametric modelling technology and command flow technology. The analysis automation was attained. Lastly, the integration system of the telescopic boom on CBR was developed by VC++, Pro/toolkit, Access2003 and APDL.

Computer aided engineering analysis and design optimization of rotary tillage tool components

A bstract: The computer aided engineering analysis and design optimization of rotary tillage tool on the basis of finite element method and simulation method is done by using CAD-software for the structural analysis. The different tillage tool parts of rotary tillage tools are geometrically constructed as a solid model. The actual field performance rating parameters along with boundary conditions are set in the software for 35 hp and 45 hp tractor. The estimated forces acting on soil-tool interface are fed into software as a loading condition. The resultant effects of loading condition on tillage blade and whole rotavator assembly were obtained from stress distribution and deformations plots. The proposed working results in identifying sufficient tolerance in changing the dimensions of rotavator frame sections and side gear box for removing the excess weight in a solid section and also to raise the weight of blade for a reliable strength. The present working model with tillage blade is analysed to new design constraints with change of its geometry for the maximum weed removal efficiency by presenting its practical results from the field performance. Keywords: rotary tillage tool, simulation, FEM, design analysis, stress, deformation, rotavator DOI: 10.3965/j.issn.1934-6344.2011.03.001-006 Citation: Gopal U Shinde, Shyam R Kajale. Computer aided engineering analysis and design optimization of rotary tillage tool components. Int J Agric & Biol Eng, 2011; 4(3): 1

Investigating the injury risk in frontal impacts of Formula Student cars: a computer-aided engineering analysis

This paper presents a parametric study of the injury risk in collisions of race cars designed for the European Formula Student competition. The study is motivated by the fact that only a limited assessment of driver safety is required for this competition. The approach was to model a Formula Student car in a mathematical dynamic model environment. A parametric study was then carried out to investigate the sensitivity of injury to various system variables. These were the crash pulse, the occupant stature, and the occupant posture. These system variables, under close examination, can be changed to alter the occupant kinematics or, in other words, they change the injury risk. The results of the analysis showed that the risk of injury in a frontal impact was dependent on the system variables. The risk of an abbreviated injury scale (AIS)2+ injury was 22.3 per cent in the baseline constant- g test, increasing to 35.2 per cent in the worst case. For AIS3+ the values were 5.1 per cent and 11 per cent, respectively. The study also showed that the occupant restraint conditions in a Formula Student car had a significant influence on the distribution of the injury risk between the body regions. The variation in the injury risk highlighted by this study, both in absolute terms and in the distribution between the body regions, showed that there are limitations to the use of vehicle kinematics in their current guise as a predictive tool for the injury risk. The results of this study represent a significant step in the understanding of the injury risk in a Formula Student frontal impact.

Development of a design verification methodology including strength and fatigue life prediction for agricultural tractors

During the operations of an agricultural tractor, front axle and front axle support encounter the worst load conditions of the whole tractor. If the design of these components is not verified by systematic engineering approach, the operators of the tractor may face with sudden failures. This paper aims to develop a verification method, which involves testing an agricultural tractor on a special test track and agricultural field and together with the computer aided engineering analysis, in order to prevent such failures in the lifetime of the agricultural tractor. For this purpose, a strain gage data acquisition system has been designed to measure the strain values on the component in order to determine maximum principle stresses for the calculation of overload safety on the agricultural field and stress data for the prediction of fatigue life on a radial washboard test track. The cycle number of these stress data for the fatigue analysis has been established by rainflow cycle counting method. Total fatigue damage for the front axle support has been calculated considering damage accumulation hypothesis defined by Miner.

열가소성 복합소재를 이용하여 사출성형 한 PEMFC용 bipolar plate의 전기전도도 및 기계적 특성 연구

본 논문은 매트릭스 수지로 LCP(Liquid crystal polymer)를 사용하였으며, 기계적 특성 및 화학적 특성을 증대시키기 위해 주 첨가제로 synthetic graphite, expanded graphite와 보조 첨가제로는 carbon black을 사용하여, 함량 별로 복합소재를 제조하였다. 사출성형 전 CAE 프로그램으로 해석을 하였으며, 유동성과 섬유 배향을 예측 했다. 복합 소재는 전동식 사출기를 이용하여 ASTM 복합 시편으로 사출성형 하였으며, 시편을 four point probe 장치를 사용하여 전기전도도를 측정/비교 하였으며, 기계적 강도는 굴곡강도, 굴곡탄성률, 충격강도를 측정하였다. 첨가제가 증가할 수록 전기전도도는 증가하나 첨가제의 brittle한 특성으로 인해 기계적 강도는 감소하는 것을 확인 할 수 있었다. This research aims to develop polymer composites which can be used for PEMFC bipolar plate by injection molding process. Considering the moldability and stiffness, we used LCP(Liquid crystal polymer) as base resin. In order to improve electrical conductivity and mechanical properties, we chose carbon black, and both synthetic graphite and expanded graphite. The composites with different recipe are prepared for injection molding of PEMFC bipolar plate and CAE(Computer Aided Engineering) analysis was performed to predict melt flow and fiber orientation We did successfully fabricate the ASTM specimens by injection molding, and measure the electrical conductivity of the samples by using four point probe device. We measured mechanical properties such as flexural strength, flexural modulus and Izod impact strength. Conclusively, the electrical conductivity increased with increasing additive concentration, but both flexural strength and Izod impact strength decreased due to the brittle nature of carbon-based additives.

A CAE/CAI Integrated Method for Sheet Metal Forming

With the development of computer technology, Computer Aided Engineering (CAE) and Computer Aided Inspection (CAI) are more widely used in stamping products for design and manufacture, but there is a lack of link between each other. On the one hand, results of CAE analysis are not effectively used and evaluated; the other hand, single CAI is not able to analyze reasons for wrinkle, crack, or springback in stamping products. To compensate these shortcomings, a CAE/CAI integrated method is established to ensure information sharing between of them, which is helpful for guiding the design of sheet metal forming. By this method, the feasibility of sheet metal forming is analyzed and forecasted, and the results of deformation are effectively assessed by 3D comparison, 2D comparison and GD&T inspection. And ultimately the superiority of CAE/CAI Integrated method is proved by case study.

Key Technologies of CAE Data Process Procedure Based on Knowledge Engineering

It is time consuming and low efficiency to process result data for car simulation,due to the fact that a lot of manual and repeated work needed in the post processing procedure.To solve the problem,taking post process of computer aided engineering(CAE) as research object,a study is conducted for CAE post process platform which is explored to embrace knowledge based engineering(KBE).The knowledge building system and user define feature are made as the goal direction,the standard of enterprise and experience of CAE analysis are united together,and various development toolkits under the HyperWorks platform are used comprehensively.A platform is designed and accomplished through secondary development in HyperWorks environment.Some key technologies are presented in this platform,such as user defined template,and automatic data collector.The practice in the real industry models shows that the platform provides an efficient,professional,and reliable toolkit for CAE engineers.

Optimum SUV bumper system design considering pedestrian performance

Until recently, passenger cars have primarily interested in pedestrian protection performance. Nowadays, however, it is important for a sport-utility vehicle (SUV) to meet the bumper system standards for pedestrian safety. For a SUV bumper system, there are some difficulties in attaining a high level of pedestrian performance for the lower legform. An SUV has a high bumper position from the ground level, and the bumper approach angle must also be secured, which has an effect on car insurance fees. Due to these reasons, it is difficult to meet the pedestrian performance of the lower legform for an SUV. In this paper, a comparative study was performed on various SUV bumper systems, and a concept model for a SUV bumper system was developed, which is expected to meet the pedestrian performance by using the Pugh method. The design control factors were defined to affect the bumper pedestrian performance through the experiences of tests and analyses. For the noise factor to affect the pedestrian performance, the deviation of the impactor position was selected at the moment of impact. The design control factors were optimized by using the Taguchi optimization technique. For the Taguchi method, an L18 orthogonal array table of design control factors was used in the optimization process. Particularly, for the optimization of the bumper corner region, an optimization analysis was performed three times to meet pedestrian performance. Based on the results of the Taguchi optimization method, the sensitivity of the bumper design parameters was studied, and a new SUV bumper system is proposed that satisfies the pedestrian performance of the lower legform. The optimized bumper system should obtain a full Euro-NCAP score of 6 points for the bumper test. The pedestrian performance of the optimized bumper system is validated by using a CAE (Computer Aided Engineering) analysis, which has been proven to be in accurate. A comparison between the test and analysis results is shown for the validation of accuracy. By using the optimized bumper system, the tests and development costs of a bumper can be reduced.

A scene graph based visualization method for representing continuous simulation data

This paper proposes a scene graph based visualization method that can verify time-varying continuous analysis simulation in a virtual reality (VR) environment by using the computer-aided engineering (CAE) data of structural analysis in product development. In previous research, the use of CAE analysis data has been problematic because of the lack of any interactive simulation controls for visualizing continuous simulation data. Moreover, the research on post-processing methods for real-time evaluation of CAE analysis data has not been sufficient. We therefore propose a scene graph based visualization method for representing continuous simulation data. The method can continuously visualize static analysis data independently of any timeline; it can also continuously visualize dynamic analysis data that varies in relation to the timeline. The visualization system for continuous simulation data, which includes CAE2VR Middleware that interfaces with various formats of CAE analysis data as well as functions for visualizing continuous simulation data and operational functions, enables users to verify simulation results with more realistic scenes.

The Optimization for Design of the Parameters of Spiral Baffle

A methodology for optimization of the development of the spiral baffle based on the scientific molding approach is presented. The function of the spiral baffle, a mold cooling system components is used to convey the coolant to the tip and back in the form of a helix. It makes a very homogeneous temperature distribution of the mold. Some design parameters of the spiral baffle, such as spiral angle, pitch …etc. are important for it to achieve a good performance. In this work, we propose a methodology to optimize the design parameters based on computer aided engineering analysis and the scientific molding approach. The scientific molding is a scientific way to detect in which area a defect lies and determine the optimal molding parameters with experimental data. It provides an alternative besides the traditional optimization methods to determine the injection molding parameters, such as injection velocity, holding pressure, …, etc. In order to illustrates how to implement this methodology to determine the design parameters of the spiral baffle. The experiment is proceeded and to validate the results of the proposed method.

On Obtaining Dynamic and Static Characteristics of Heavy Load Deflection Angle Milling Head by CAE and Experiment Techniques

The heavy load deflection angle milling head is an important functional component of 5-axis CNC machine tool, which is used for large and complex free-form surface processing. The characteristics of this kind of milling head are implementing multiple degrees of freedom motion with revolution and deflection angle simultaneously. Obtaining milling head dynamic and static characteristics is a pre-requisite problem to resolve for the development and research of heavy load deflection angle milling head independently. Dynamic characteristics are obtained through combination with CAE (Computer-aided Engineering) technique and experiment validation. For CAE analysis, the main parts of milling head are glued together considering milling head operating at a specific position. Experimental validation is carried through with initial fixing constraint style, which validates the correctness of CAE technique. Experimental and CAE analysis results are compared and analyzed. Therefore, exact dynamic characteristics of milling head and unsubstantial segments and its influence factors are gotten. Static characteristic is obtained considering milling head operating in different posture by CAE technique. The analytical method of three points at half of cutter are loaded is introduced. Calculated results indicate that the deformation of tool tip is the largest when milling head operating in 45° posture, which corresponds with the deformation situation of the milling head operating in workshop. The analytical results of dynamic and static characteristics of milling head provide theoretical and experimental support for structure optimization and improving of heavy load deflection angle milling head.

Application of Computer-Aided Process Engineering and Exergy Analysis to Evaluate Different Routes of Biofuels Production from Lignocellulosic Biomass

The fast development of the bioethanol industry based on sugar cane in Colombia and Latin America has contributed to the debate on “food versus fuel” and environmental impact. In this paper, the integrated use of sugar cane bagasse was analyzed for the second generation of biofuels production, which does not affect the food supply. A case study was used to demonstrate the approach. The case study involves the conversion of 1200 tonnes/day of sugar cane bagasse to ethanol. Computer-aided process engineering tools together with exergetic and life cycle analyses using Aspen and SimaPro software were used for the screening of process configurations and the identification of opportunities for improvement. Additionally, the application of process integration principles to the selected topology identified strategies to conserve natural resources and reduce the environmental impact of the process.

전도성 복합재료를 이용한 PEMFC용 separator 사출성형 제조 및 전기전도성 평가

본 논문은 매트릭스 수지로 PPS(Poly(phenylene sulfide))와 PP(Polypropylene)를 사용하였으며, 물리적 및 화학적 특성을 증대시키기 위해 주 첨가제로는 팽창 흑연, 합성 흑연과 보조 첨가제로는 유리 섬유, 카본 섬유, 카본 블랙을 사용하여 총 3가지의 복합소재를 제조하였다. 제조한 복합소재를 이용하여 사출 성형 및 평가 전에 CAE(Computer Aided Engineering)해석 프로그램을 통하여 해석을 하였으며, 사출성형을 통하여 사출조건(사출 압력, 가열시간, 금형온도 등)을 최적화하였다. 일반 사출성형의 경우 온도의 제한과 성형성의 한계가 있어 유동성이 낮은 복합소재의 경우 사출성형이 어렵기 때문에 이를 보완하기 위해 E-MOLD와 사출압축 기능을 함께 사용하여 복합소재의 성형성을 향상 시켰다. 사출 성형 된 각각의 최종 시편을 four point probe 장치를 사용하여 전기전도도를 측정/비교 하였고, 3가지 복합소재 중 PP/SG/CB를 혼합하여 제조한 복합소재가 성형성 및 전기전도도가 우수한 것을 확인하였다. This research aims to develop polymer composites which can be used for PEMFC separators by injection molding process. Considering the moldability and stiffness, we used PPS(Poly(phenylene sulfide)) and PP(Polypropylene) as base resin. In order to improve electrical conductivity and physical properties, we chose glass fiber, carbon fiber, carbon black, and both expanded graphite and synthetic graphite. The 3 type composites are prepared for injection molding of PEMFC separators. and CAE(Computer Aided Engineering) analysis was conducted to optimize injection processing parameters(injection pressure, heat time, mold temperature etc.). We did successfully fabricate the separators by injection molding, and measure the electrical conductivity of the samples by using four point probe device. Conclusively, PP/SG/CB composite showed better both electrical conductivity and moldability than the others.

Plasticity model for metals under cyclic large-strain loading

This paper deals with mathematical modeling of one of the effective technologies of plastic metal forming — multistep cold metal forging. Experimental results are given on the plastic behavior of metals under cyclic loading at large strains accumulated for one cycle. Based on the experimental data obtained, a plasticity model is developed and shown to be effective in testing and improving the technology of forging a nut blank by using a computer-aided engineering analysis system.

Musculoskeletal computational analysis of the influence of car-seat design/adjustments on long-distance driving fatigue

The main causes for long-distance driving fatigue experienced by vehicle drivers are investigated computationally using musculoskeletal modeling and simulation methods. A rigid-body model of a prototypical adjustable car seat is constructed as a part of the present work and combined with a public-domain musculoskeletal model of a seated human. Seated-human/car-seat interactions associated with typical seating postures of the vehicle driver are analyzed using the inverse-dynamics approach while the “ minimum-fatigue” criterion is utilized to deal with the muscle redundancy problem (i.e., with the problem that human-body contains more muscles than what would be typically needed to drive various body joints). The results obtained show that various seat adjustments (e.g., back-rest inclination, seat-pan horizontal track position, etc.), driver's back supports (e.g., presence/absence of lumbar support) and the nature of seat upholstery (e.g., fabric vs. vinyl) can have complex influence on the muscle activation, joint forces, soft-tissue contact normal and shear stresses, all of which not only affect the comfort perception of the driver but also their feel of fatigue. Subsequently, the results of the present work along with relevant public-domain literature findings (e.g., subjective driving-fatigue assessments provided by human test subjects and human-body/seat contact-force measurements) are used to construct a preliminary long-distance driving-fatigue function. Relevance to industry it is argued that the computer-aided engineering analysis introduced in the present work should help speed-up the design of new high-comfort car seats. These seats are currently being mainly designed using empiricism, legacy knowledge and extensive, time-consuming and costly prototyping and experimental/field testing.

무광부식 패턴을 갖는 자동차 내장부품인 HD Switch Panel의 제조 및 전사성 평가

본 논문에서는 미세 무광부식 패턴을 갖는 HD Switch Panel 자동차 부품을 개발하는 것으로, 제품 디자인을 통해 금형을 설계, 제작하였다. 최적화된 금형 제작을 위하여 CAE(Computer Aided Engineering)해석을 통하여 사출성형 공정에서 나타날 수 있는 문제점과 부품의 수축 변형을 정량적으로 예측하였다. 그리고, 금형표면의 가열온도와 실제 금형온도를 비교함으로써 공정변수 조절을 통해 사출성형조건의 최적화도 달성할 수 있었다. 한편, 순간금형표면가열방식을 이용한 성형기술인 E-MOLD를 적용하여 자동차 내장부품용 HD Switch Panel 사출성형품을 제작하였고, 전자현미경과 원자현미경을 이용한 표면 평가 및 광택도 측정을 통하여 무광부식 패턴의 전사율 향상으로 인한 무광 특성이 향상됨(2.5이상<TEX>$\to$</TEX>1.5~1.7)을 확인하였다. In this paper, we designed and manufactured HD Switch Panel parts with micro-etched pattern. By using CAE analysis, we could predict weld-line positions and the amount of shrinkage during injection molding process. We measured the temperature distribution of the mold surface so that we could optimize the processing conditions such as mold temperature. In order to increase the transcription of micro-etched pattern, we applied the E-Mold technology and evaluated the effect of mold temperature on the surface quality. We concluded that the etched pattern was improved(more than 2.5<TEX>$\to$</TEX>1.5~1.7) through the measurement of surface gloss and the observation of both SEM and SPM images.

Development of a lightweight CAE middleware for CAE data exchange

Computer-aided engineering (CAE) analysis is considered essential for product development because it decreases the simulation time, reduces the prototyping costs, and enhances the reusability of product parts. The reuse of quality-assured CAE data has been continually increasing in order to shorten the product development cycle and to improve the product quality. However, less attention has been paid to systematic research on the interoperability of CAE data because of the diversity of CAE data and because the structure of CAE data is more complex than that of CAD data. In this paper, we suggest a CAE data exchange method for the effective sharing of geometric and analysis data. The method relies on heterogeneous CAE systems, a virtual reality system, and our developed lightweight CAE middleware for CAE data exchange. We also designed a generic CAE kernel, which is a critical part of the CAE middleware. The kernel offers a way of storing analysis data from various CAE systems, and, with the aid of a script command, enabling the data to be translated for a different system. The reuse of CAE data is enhanced by the fact that the CAE middleware can be linked with a virtual reality system or a product data management system.

Quick Profile Die Balancing of Automotive Rubber Seal Extrusion by CAE Technology

The extrusion process of a type of automotive rubber seal was considered by using Computer Aided Engineering (CAE) technology. Based on the die balancing requirement, CAE technology was utilized to speed up the die development and balancing process. The rubber material was EPDM and unacceptable extrusion deformation was found by using a parallel die. More balancing dies were then designed following the procedures proposed by the die balancing method and the effect of them was evaluated with respect to CAE analytical results. It was found that the addition of an opening section in the die would provide a more uniform velocity distribution at the die exit than the parallel die. The length of opening section was also found to affect the die balancing and so an optimum length of the opening section was determined by CAE analysis. Further optimization of the die was carried out by adjusting the local length of the opening section. Finally, a real die was cut based on the optimization results and used for production. Ideal profile products were obtained and very small and acceptable deviation from the die was observed, which validated the advantage and accuracy of CAE technology combined with die balancing requirement.