Commercial Computer-aided Engineering Research Articles

Investigation of an automotive subsystem submitted to vibration loads considering scatter of influence parameters

Modern vehicles contain numerous subsystems for comfort, safety, electrification and autonomous driving functions that are mounted to the body-in-white structure. These subsystems are submitted to stochastic vibrational loads induced mainly by the road unevenness. The vibration fatigue behaviour of the subsystems and their connection to the body-in-white structure depend on a great number of influence parameters and associated uncertain scatter bands that are usually unknown and difficult to consider in the design process. This study investigates the oscillation behaviour and fatigue life of a current car component excited by vi-brational loads focusing on scatter of relevant influence parameters (mass, stiffness) on a pronounced statistical sample basis. An experimental modal analysis is used to determine eigenmodes and damping characteristics for the three variants: nominal value, increased mass and reduced stiffness. As a further experimental investigation vibration fatigue tests are performed. A probabilistic approach using a simulation tool chain with the aid of commercial computer aided engineering (CAE) programs is proposed to consider scatter effects on the fatigue life of the component submitted to vibration loads and its connection to the body-in-white structure. The simulation fidelity when using uncertain broader scatter bounds is compared to simulation fidelity using both measured data and modal analysis output. Furthermore, correlations between the vibration behaviour and the fatigue of the component are derived. Finally, the hardware fatigue tests results are compared to the simulation results. A very good agreement for eigen-modes, frequency response functions and fatigue lifetime was observed between simulation model and experimental findings. A significant accuracy improvement of the fatigue life simulation using the introduced probabilistic simulation method considering measured scatter bounds for uncertain input parameters is presented.

Investigations on visualization and interaction of ship structure multidisciplinary finite element analysis data for virtual environment

Although the extraction and sharing of important data in the finite element model (FEM) and analysis data is particularly significant in the ship structure collaborative design process, the efficiency of sharing finite element analysis (FEA) data using a standardized neutral format is still relatively low, which is attributed to the format that has to accommodate various data types generated by different commercial computer aided engineering (CAE) software and multidisciplinary analysis applications. Aiming to solve the problem of efficient visualization and sharing of heterogeneous FEA data in ship structure collaborative design and review, we proposed a new FEA data visualization framework for virtual environments (VE) to realize multidisciplinary data sharing in the collaborative design process, where only essential finite element (FE) information is stored to reduce the weight of the model and analysis data. In addition, the visualizing results can be updated in response to the modification of the model geometry and simulation variables. Furthermore, we implemented a general system based on our data framework. To maximize the efficiency of managing multidisciplinary data (statics, dynamics, ultimate strength), the system adopts a client/server (C/S) architecture and hierarchical management of data structures. The virtual visualization of these complex FEA data effectively enhances the efficiency of scientific communication, model evaluation and validation, and interdisciplinary discussion of research findings. Eventually, examples from commercial CAE software are provided to demonstrate the effectiveness and versatility of the system.

Simulation and Experimental Verification of Dynamic Characteristics on Gas Foil Thrust Bearings Based on Multi-Physics Three-Dimensional Computer Aided Engineering Methods

This paper presents a method to simulate the dynamic operating characteristics of a gas foil thrust bearing based on linear elastic support and constant ambient temperature to mimic the transient structure–fluid interactions. In the physical model, the top and bump foils are simply represented by an infinite number of Hookean springs attached to a solid wall with a small amount of deformation, whereas the gas film in the bearing is under quasi-steady lubrication flow conditions with hydrodynamic pressure distributed on the little-deformed top foil. A three-dimensional multi-physics model in a cylindrical coordinate system is established via a commercial computer-aided engineering software package to predict the nominal dynamic characteristics of the gas foil thrust bearing. To verify the multi-physics model, an experimental bench was built in-house to measure the thrust force on the support of the bearing. With the pertinent bearing parameters being entered into the package, the simulations agree well with the experimental thrust forces. As a further step, a simulation model of a clamped-rotor gas foil thrust bearing design was thoroughly investigated under nominal operating conditions, resulting in predictions of underdamped oscillations in rotor motions. The phenomenon could be described using a linear mass–spring–damper model that is dependent on the gas film thickness. The stiffness and damping coefficients could serve as a base reference for rotor dynamics analysis. This concludes the potential development of a digital twin for gas foil thrust bearing systems.

A Novel Implementation of Energy-Based Homogenization Method

This paper develops a novel implementation of energy-based homogenization method, which has rigorous mathematical foundation of the homogenization method, and also efficiently and accurately predict the mechanical performance of composite materials. The feature extraction, domain discretization and periodic boundary condition application are carried out automatically in this method. Besides, this model remains a fairly small scale and it could be directly embedded into structure optimization algorithms. The numerical calculation could be easily implemented with a commercial computer aided engineering (CAE) software and the integration algorithm was realized by the third-party language. This article explains the scheme of the CAE/CAD integration in homogenization method and the theoretical model of the energy-based homogenization for cellular solid element and shell element. Furthermore, two examples for cellular solid and stiffened plate, and its implementation in cellular material design are presented to illustrate the verification of the proposed method.

Estimation of the Core Losses of Induction Machines Based on the Corrected Epstein Test Method

A revised method based on the standard Epstein test is proposed to improve the accuracy of the estimation of the core losses of induction machines (IMs). Since the magnetic field strength patterns at the four corners of the standard test samples are non-uniform, high-order excess losses at the corners would deteriorate the accuracy of the model for core losses. To address this issue, test samples were designed which have an appropriate geometry for the measurement of core losses under the test conditions. The excess losses could be eliminated by introducing an air-gap magnetic reluctance at the four corners so that the core-loss data from the tests consist of only hysteresis and eddy current parts. In experimental validations, three 5-HP IMs were bench-tested for the verification of the core-loss estimation. The use of commercial computer-aided engineering software packages allowed for the estimated core losses to be recorded and compared. The results indicate that high-order excess losses could account for 7% of the total core losses.

Аналітичне дослідження контактної поведінки ділянки трубопроводу з в’язкопружною ремонтною накладкою

In this paper an analytical study on a stress-strain state of a steel pipeline section with a repair fi-berglass viscoelastic layer is described. The layer is considered long enough that allows to solve the problem in a flat axisymmetric statement. The analytical model including accounting of an isotropic viscoelasticity involves the need to construct and solve the boundary value problem for a system of integro-differential equations. In order to do it an approach based on a method of differentiation of integral equations is proposed. It is shown that for the initial time moment a solution of viscoelastic problem coincides with an elastic solution. Calculation results are presented as displacement and stress distributions versus radius and time curves. The viscoelastic model lets detect and discover such impor-tant properties of viscoelasticity as an increase of displacement over time and a stress relaxation in the composite layer. It is observed that at the same time the stress relaxation in the layer causes an increase of dangerous circumferential stresses in the steel pipeline. According to these results a conclusion about an impact of viscoelasticity on an overall assessment of strength of the construction is made. Also it is shown that for the specific set of physical and geometrical parameters of the construction stress relaxa-tion in layer occurs in the moment of time with a value 200 hours and the maximum circumferential stress value increases by seven percent. The time result coincide with relaxation time obtained using numerical model based on a finite-element method of a commercial computer-aided engineering com-plex. The stress increase result also responds to the numerical assessment and this value can be much higher in case of stress concentration due to presence of defects in pipeline walls. Proposed analytical model allows to save computational resources and to extend its application to more complex cases of the stress-strain state.

INTEGRATION OF CAD AND CAE IN SME’S FOR PRODUCT DEVELOPMENT

Small manufacturing enterprises face a number of challenges when integrating computer aided design (CAD) tools and computer-aided engineering (CAE) tools into their design processes. One of the most significant challenges is interoperability across the wide range of commercial CAD and CAE tools. Although many of these tools support industry data standards and claim to be interoperable, the connection between them is not seamless. This paper summarizes studies of tool integration activities at one small manufacturer. The paper shows the enhancement of the product development process resulting from replacement of a two dimensional CAD system with a three-dimensional CAD system and creation of an inhouse capability to perform finite element analysis (FEA), replacing analysis that had previously been outsourced. As a result of these experiences, the manufacturer learned that improved productivity and superior designs could be obtained by integrating analysis into the design process at the earlier stages of conceptual and preliminary design.

Development of a lightweight frame for a 40-foot flatbed trailer by using CAE-based structural optimization

In this study, a novel ultra-lightweight frame for a flatbed trailer is developed; it has a completely different layout from conventional ladder-type frames and is developed by applying structural optimization using commercial computer aided engineering (CAE)-based software. The proposed process of design optimization consists of two main steps: an initial design step to obtain the optimum layout (or topology) of the structure and a size/shape optimization step to determine its detailed geometric dimensions. In the topology optimization step, an initial design of the frame is generated to obtain the maximized global system performance measures, such as static stiffness or natural frequencies, for which GENESIS, a commercial optimization software package, is used in this investigation. For size and shape optimization, thicknesses of the member plates and the boundary shapes are optimized by using the Taguchi method, in order to minimize further the mass of the frame without violating design constraints on local performance measures such as the allowable stress limit. In addition, manufacturability is also considered during the detail design step of size and shape optimization. As a result, the optimized lightweight frame has improved bending and torsional rigidities while its mass is reduced by 24.5 per cent as compared to that of the original model.

Computational wear simulation of patellofemoral articular cartilage during in vitro testing

Though changes in normal joint motions and loads (e.g., following anterior cruciate ligament injury) contribute to the development of knee osteoarthritis, the precise mechanism by which these changes induce osteoarthritis remains unknown. As a first step toward identifying this mechanism, this study evaluates computational wear simulations of a patellofemoral joint specimen wear tested on a knee simulator machine. A multibody dynamic model of the specimen mounted in the simulator machine was constructed in commercial computer-aided engineering software. A custom elastic foundation contact model was used to calculate contact pressures and wear on the femoral and patellar articular surfaces using geometry created from laser scan and MR data. Two different wear simulation approaches were investigated—one that wore the surface geometries gradually over a sequence of 10 one-cycle dynamic simulations (termed the “progressive” approach), and one that wore the surface geometries abruptly using results from a single one-cycle dynamic simulation (termed the “non-progressive” approach). The progressive approach with laser scan geometry reproduced the experimentally measured wear depths and areas for both the femur and patella. The less costly non-progressive approach predicted deeper wear depths, especially on the patella, but had little influence on predicted wear areas. Use of MR data for creating the articular and subchondral bone geometry altered wear depth and area predictions by at most 13%. These results suggest that MR-derived geometry may be sufficient for simulating articular cartilage wear in vivo and that a progressive simulation approach may be needed for the patella and tibia since both remain in continuous contact with the femur.

Analysis of the roll properties of a tubular-type torsion beam suspension

Tubular-type torsion beam rear-suspension systems are widely used in small passenger cars owing to their compactness, light weight, and cost efficiency. It is already known that the roll behaviour of a torsion beam suspension system can be approximated to that of a semitrailing arm suspension system. By this kinematic assumption, analytical equations to obtain the roll centre height, roll steer, and roll camber have already been developed in terms of geometry points. Therefore, this paper proposes an analytical method to calculate the torsional stiffness of a tubular beam from its cross-section area based on the assumption that a tubular beam is a series connection of finite lengths with a constant cross-section. In addition, a potential energy method is proposed to calculate the roll stiffness of a tubular torsion beam suspension system based on considering the bushing stiffness and torsional stiffness of the tubular beam without the use of any commercial computer-aided engineering (CAE) software. The torsional stiffness and roll stiffness predicted using the proposed method showed errors of about 4 per cent and 3.3 per cent respectively, when compared with results from commercial CAE software.

플라스틱 DVD-Tray의 박막 사출성형을 위한 최적화 설계 Simulation에 관한 연구

사출성형은 다양한 형태의 제품을 대량 생산할 수 있는 플라스틱 성형 공법중의 하나이다. 플라스틱 제품을 만들기 위해서는 고상의 재료를 액상으로 녹인 후 다시 고상으로 굳히는 과정을 거치는 데, 이 과정 중에 많은 문제점들이 발생을 하게 된다. 과거에는 이러한 문제를 해결하기 위해서 성형 후 금형 설계 변경 등의 시행착오적 방법을 사용하였으나, 성형과정에 대한 사출성형 CAE(Computer Aided Engineering)를 적용함으로써, 사전에 문제점을 파악하는 기술이 도입되었다. 플라스틱 제품의 큰 문제점 중 하나가 치수안정성이다. 특히 박막사출성형품은 게이트의 위치, 냉각채널과 온도에 따라서 변형량이 크게 달라진다. 본 연구에서는 현재 Stackmold방식으로 4개의 Cavity에 4개의 Hot-Runner가 설치된 금형을 통해 생산중인 DVD Tray 박막사출제품의 생산 원가 절감을 위해서 Cavity하나에 한 개의 Hot-Runner를 설계하기 위해서 CAE 해석을 통해 게이트의 위치, 냉각채널과 온도에 따라 비교하여 해석해 최적의 제품 설계를 하였다. CAE 해석에는 상업화된 CAE 프로그램인 Moldflow를 사용하였고, 수지는 PC+ABS를 사용하였다. 【Injection molding is one of plastic forming technology which can easily mass-produce plastic parts with various and even complex shape. The technology has lots of difficulties in making a good part due to phase change of material, high applied pressure, and fast melt flow speed in the cavity. To overcome the problems, they had to make trial and error method until the CAE(Computer Aided Engineering) could be a tool for concurrent engineering. In this paper, we investigate the optimal design for a plastic DVD tray part by systematic approach of the commercial CAE program. In design, we should consider two objectives which are both dimensional stability and cost-down. The dimension of the part is crucial because the tray should carry a DVD correctly, but the part is too thin to injection-mold easily. In order to improve the moldability, the mold is designed in the form of stack mold which is a kind of 4 hot runner system. In first, we changed the stack-mold system with one hot-runner to cost down, and decided the optimal position of the gate. After that, we investigate the effect of both the layout of cooling channels and the cooling temperature on the shrinkage of the DVD tray. A optimal simulation approach, the gate design is 2Gate#3 and the layout is Case2 cooling line as the optimal temperature of $70^{\circ}C$ . The Moldflow and PC+ABS are used for the CAE program and material respectively.】

Material properties for process simulation

This paper reviews the recent developments in material property modelling and its applications in processing simulation. Many material properties needed by process simulation can now be readily provided, such as the solidification properties and high temperature stress–strain curves. The solidification properties are affected by changes in composition within the specification range of an alloy; such changes in properties then affect casting simulation results. The mechanical properties are calculated by considering two competing deformation mechanisms (dominated by either dislocation glide or dislocation climb), with automatic selection of the dominant mechanism. Sample calculations are given for a variety of engineering alloys, including steels, aluminum, titanium, and nickel-based superalloys. The material properties data calculated can now be passed directly into commercial computer-aided engineering packages for casting and deformation simulation.

3D printing technique applied to rapid casting

PurposeThe purpose of this paper is to verify the feasibility and evaluate the dimensional accuracy of two rapid casting (RC) solutions based on 3D printing technology: investment casting starting from 3D‐printed starch patterns and the ZCast process for the production of cavities for light‐alloys castings.Design/methodology/approachStarting from the identification and design of a benchmark, technological prototypes were produced with the two RC processes. Measurements on a coordinate measuring machine allowed calculating the dimensional tolerances of the proposed technological chains. The predictive performances of computer aided engineering (CAE) software were verified when applied to the ZCast process modelling.FindingsThe research proved that both the investigated RC solutions are effective in obtaining cast technological prototypes in short times and with low costs, with dimensional tolerances that are completely consistent with metal casting processes.Practical implicationsThe research assessed the feasibility and dimensional performances of two RC solutions, providing data that are extremely useful for the industrial application of the considered technologies.Originality/valueThe paper deals with experimental work on innovative techniques on which data are still lacking in literature. In particular, an original contribution to the determination of dimensional tolerances and the investigation on the predictive performances of commercial CAE software is provided.

Comparison of the warpage optimization in the plastic injection molding using ANOVA, neural network model and genetic algorithm

Plastic injection processes comprise plastication, injection, packing, cooling, ejection and process/part quality control applications. These steps are followed for the parts, which are designed to be produced by plastic injection method. Having initial knowledge about the process that will be undertaken is necessary because of present-day competitive conditions that forces us to produce faster and cheaper with a higher quality, such as minimum warpage, sink marks, etc. Computer-aided analysis and engineering softwares are used in order to meet this necessity. For plastic injection process, one of the commercial computer-aided engineering softwares is the MoldFlow Plastic Insight. In this study, best gate location, filling and flow, warpage applications have done for minimum warpage of plastic part with this tool. Process parameters such as mold temperature, melt temperature, packing pressure, packing time, cooling time, runner type and gate location are considered as model variables. The effects of process parameters for thin shell plastic part were exploited using both design of experiment (DOE), Taguchi orthogonal array and finite element software MoldFlow (FE). The most important process parameters influencing warpage are determined using finite element analysis results based on analysis of variance (ANOVA) method. Artificial neural network (ANN) is interfaced with an effective GA to find the minimum warpage value.

A computational model for the prediction of total knee replacement kinematics in the sagittal plane

A computational model has been developed using a current generation computer-aided engineering (CAE) package to predict total knee replacement (TKR) kinematic in the sagittal plane. The model includes friction and soft tissue restraint varying according to the flexion angle. The model was validated by comparing the outcomes of anterior–posterior (A–P) laxity tests of two contemporary knee replacements against data obtained from a knee simulating machine. It was also validated against predictions from a computer model reported in the literature. Results show good agreement in terms of A–P displacements. Further tests were performed to determined the influence of the soft tissue restraints varying with flexion angle. This work represents the first attempt to use a sophisticated commercial CAE package to predict TKR motions and the advantages of the modelling procedure chosen are discussed.

A computer program system for transient electromagnetic analysis on a tokamak device

A description is given of EDDYTOR, an eddy-current analysis and evaluation code system for tokamak reactors. The EDDYTOR system is able to calculate eddy currents, electromagnetic forces, stress and deformation, and plasma position and control properties. The program was designed to operate on an engineering work station utilizing a commercial CAE (computer-aided engineering) package. It has been shown to save on design time and to maintain overall design consistency, since a comprehensive design analysis can be performed within the same system. >

CAE software in manufacturing engineering education

This paper examines the role of commercial computer-aided engineering (CAE) software in manufacturing engineering education. The proliferation of computing in industry demands that a significant proportion of students' timetables be devoted to CAE aspects, in order that they may gain an appreciation of the capabilities and limitations of such systems. However, it is also important to present this computing element so that it does not overwhelm other, equally important parts of the manufacturing engineering syllabus. The aim must be to integrate CAE courses into the curriculum, make real academic demands of students and to ensure a good understanding of CAE.

Palladio: An exploratory environment for circuit design

Palladio is a circuit design environment for experimenting with methodologies and knowledge-based, expert-system design aids. Its framework is based on several premises about circuit design: (1) circuit design is a process of incremental refinement; (2) it is an exploratory process in which design specifications and design goals coevolve; and (3) most important, circuit designers need an integrated design environment that provides compatible design tools ranging from simulators to layout generators, that permits specification of digital systems in compatible languages ranging anywhere from architectural to layout, and includes the means for explicitly representing, constructing, and testing such design tools and languages. The Palladio environment is part of a growing trend toward creating integrated design environments and away from isolated design aids. Recently several commercial computer-aided engineering (CAE) workstations have emerged, providing multiple-level, circuit-specification entry systems and integrated analysis aids. Integrated circuit designers have a special need for such workstations because of the complexity of large integrated circuits and the high costs of prototyping them.