CAE Model Research Articles

CAD and CAE Integration Using Multi-Abstraction Mon-Manifold Modelling Method

AbstractIn spite of the widespread use of CAD systems for design and CAE systems for analysis, the two processes are not well integrated because CAD and CAE models inherently use different types of geometric models and there currently exists no generic, unified model that allows both design and analysis information to be specified and shared. In this paper a new approach called the CAD/CAE-integrated approach is proposed that creates and manipulates a single master model containing different types of all of the geometric models required for CAD and CAE. Both a solid model (for CAD) and a non-manifold model (for CAE) are immediately extracted from the master model through a selection process. If a design change is required, the master model is modified by the feature modelling capabilities of our system. As a result, the design and analysis models are modified simultaneously and maintained consistently. This system also supports feature-based multi-resolution and multi-abstraction modelling capabilities pr...

Development of CAE System for Structural Design of LSI Packages

A practical structural design system for LSI packages has been developed based on object oriented and graphical user interface technologies. An object-oriented technology is applied for creating product model-based analytical model (PBAM) which is independent of analytical method or tool. It is easy to create any CAE model from the PBAM. Graphical user interface is another effective technology for easy operation. Design engineers only have to select a model of interest and revise the dimensions or materials of the package, if necessary. As soon as they finish revising the input data, a CAE model such as finite element meshes are generated and the analysis starts automatically. The life of the solder joints, for example, is automatically evaluated and the results are displayed on a CRT. This system is very effective for designing new, highly reliable LSI packages in a short time.

Simple Finite Element Model with Beam Elements for Panel Part of Spot-Welded Frame-Panel Structure.

The high quality of the cab design and the vibration reduction of the cab are needed for the vehicle type construction machinery. As these countermeasures, the structure analysis and vibration analysis are carried out by large-scale CAE modeled with the shell elements in detailed design stage. But, when the design change is required in the evaluation using the CAE in detailed design, we have to make large-scale CAE model again. In the result, the prolongation of the development time and the increase of the calculation cost are caused. From such background, it is necessary to be simulated the strength and the vibration of the cab at the good accuracy in the conceptual design stage in order to carry out the cost reduction of the development and shortening development time. Then, the object of our study has been established the simple finite element model based on the beam elements for carrying out CAE in conceptual design stage in the design field easily. We have studied the evaluation method of torsional rigidity for the spot-welded frame which had been difficult to be calculated, and have been modeled the frame part of the cab with beam element. In this paper, we present the simple FE model with the rhombic beam elements for the panel part. We can establish the simplified FE model of the cab for static analysis and eigenvalue analysis.

STATISTICAL MODEL FOR VEHICLE BODY-IN-PRIME STATIC STIFFNESS TARGET SETTING

The vehicle body-in-prime static stiffness can significantly affect vehicle NVH, ride and handling, and durability performance. Stiffness target setting is a crucial step in a vehicle design and development process. Traditionally, benchmarking data and CAE models are used to help identify and set the target, yet they have proven to be time consuming and very subjective. On the other hand, statistical models obtained through data mining or meta-modeling have been tested and applied to various problems, including design optimization. In the present paper, we attempt to utilize this technology for providing more objective vehicle static stiffness targets. Stiffness data characteristics of various vehicle classes are benchmarked. Different statistical modeling techniques are examined using the data to set stiffness targets. The validity and limitations of these techniques are also discussed.

VIRTUAL EXPERIMENTAL DESIGN OPTIMIZATION ON CABLE-DRIVE GLASS GUIDANCE SYSTEM

This paper focuses on utilizing CAE models, DOE, and RSM to conduct a virtual experimental analysis and design on glass guidance system. The methodologies and critical design parameters are presented.

A high mileage vehicle body joint degradation estimation method

High Mileage NVH (Noise, Vibration and Harshness) performance is one of the major concerns in vehicle design for long term customer satisfaction. One of the main causes of the high mileage NVH degradation is the loss of joint stiffness of body structure due to fatigue, corrosion, loosening, wear and aging. Traditional joint test methods for determining joint stiffness before and after the mileage accumulation require joints to be cut from a vehicle body and are very time consuming and expensive. This paper presents a computational/experimental diagnostic method which can be used to identify the degradation in the stiffness of the joints of a vehicle body structure using frequency response functions measured on a body before and after mileage accumulation. The key idea in this method is to develop and use an equation relating the change in the dynamic response of the zero and high mileage vehicles to the change in the vehicle structure joint stiffness. The method is validated using a body-in-white (B-I-W) CAE model of a production vehicle.

An adaptive dynamic model for the virtual engine

The passenger car engine development process requires CAE models that deliver results for the concept phase at a very early stage and which can be further detailed on the same program platform as the development process progresses. An engine dynamics model that meets these requirements is described here.

Integrated Simulations of Gas Injection Molding Process and Part Structural Performance under a Unified CAE Model

Integrated Simulations of Gas Injection Molding Process and Part Structural Performance under a Unified CAE Model

Integrated Simulations of Gas Injection Molding Process and Part Structural Performance under a Unified CAE Model

Integrated simulations of gas injection molding process and part structural performance under a unified CAE model were carried out. An analysis algorithm based on DKT/VRT elements superimposed with beam elements representing gas channels of various section geometries was first developed to evaluate the structural reinforcement of gas channel in the design stage. During melt/gas filling process, a mixed control-volume/finite-element/finite-difference method combined with dual-filling-parameter technique was implemented to trace the advancement of melt and gas fronts. For the prediction of secondary gas penetration, flow model of isotropic-shrinkage origin was introduced. Mold cooling analysis was executed utilizing cycle-averaged boundary element method considering the cooling system. Both cooling channel and the hollowed core gas channel were modeled using line-source approach. Thermal residual stresses calculated from part temperature distribution were then combined with the structural analysis to predict part warpage. The monitor support was used as the case study. The analysis accuracy from this unified model of 2-1/2D characteristics were examined experimentally. The only difference between process simulation and structure/warpage analyses is that different values of equivalent diameters assigned to a circular pipe representing gas channel should be used, respectively.

Simulation of a mold‐cooling process for gas‐assisted injection molded parts designed with a top rib on the gas channel

AbstractThe same CAE model used for the filling and packing stage in the gas‐assisted injection molding (GAIM) process simulation was also applied to simulate the cooling phase. This was made possible by using the line source method for modeling cooling channels. The cycle‐averaged and cyclic transient mold cavity surface temperature distribution within a steady cycle was calculated using the three‐dimensional modified boundary element technique similar to that used in conventional injection molding. The analysis results for GAIM plates of a semicircular gas channel design attached with a top rib are illustrated and discussed. It was found that the difference in cycle‐averaged mold wall temperatures may be as high as 10°C, and within a steady cycle, part temperatures may also vary by about 15°C. The conversion of the gas channel into equivalent circular pipe and further simplification into two‐node elements using the line source method not only affects the mold wall temperature calculation very slightly but also reduces the computer time by 93%. This indicates that it is feasible to achieve an integrated process simulation for GAIM under one CAE model, resulting in great computational efficiency for industrial application.

Integrated simulations of structural performance, molding process, and warpage for gas-assisted injection-molded parts. III. Simulation of cyclic, transient variations in mold wall temperatures

Whether it is feasible to perform an integrated simulation for structural analysis, process simulation, as well as warpage calculation based on a unified CAE model for gas-assisted injection molding (GAIM) is a great concern. In the present study, numerical algorithms based on the same CAE model used for process simulation regarding filling and packing stages were developed to simulate the cooling phase of GAIM considering the influence of the cooling system. The cycle-averaged mold cavity surface temperature distribution within a steady cycle is first calculated based on a steady-state approach to count for overall heat balance using three-dimensional modified boundary element technique. The part temperature distribution and profiles, as well as the associated transient heat flux on plastic-mold interface, are then computed by a finite difference method in a decoupled manner. Finally, the difference between cycle-averaged heat flux and transient heat flux is analyzed to obtain the cyclic, transient mold cavity surface temperatures. The analysis results for GAIM plates with semicircular gas channel design are illustrated and discussed. It was found that the difference in cycle-averaged mold wall temperatures may be as high as 10°C and within a steady cycle, part temperatures may also vary ∼ 15°C. The conversion of gas channel into equivalent circular pipe and further simplified to two-node elements using a line source approach not only affects the mold wall temperature calculation very slightly, but also reduces the computer time by 95%. This investigation indicates that it is feasible to achieve an integrated process simulation for GAIM under one CAE model, resulting in great computational efficiency for industrial application.

Simulation of gas-assisted injection mold-cooling process using line source model approach for gas channel

Whether it is feasible to perform an integrated simulation for process simulation based on a unified CAE model for gas-assisted injection molding (GAIM) is a great concern. In the present study, numerical algorithms based on the same CAE model used for process simulation regarding filling and packing stages were developed to simulate the cooling phase of GAIM using a cycle-averaged three-dimensional modified boundary element technique similar to that used for conventional injection molding. However, to use the current CAE model for analysis, gas channel was modeled by two-node elements using line source approach. It was found that this new modeling not only affects the mold wall temperature calculation very slightly but also reduces the computer time by 95% as compared with a full gas channel modeling required a lot of triangular elements on gas channel surface. This investigation indicates that it is feasible to achieve an integrated process simulation for GAIM under one CAE model resulting in great computational efficiency for industrial application.

Digital speckle interferometry: some developments and applications for vibration measurement in the automotive industry

This paper presents an overview of some recent progress in digital speckle interferometry and its application for vibration measurement in the automotive industry. It describes three methods to generate raw vibration fringe patterns with better quality; provides speckle averaging, phase shifting, and phase reconstruction iteration procedures to produce a high-quality and noise-free fringe pattern; illustrates one single setup for measuring both vibration deformation and geometric shape of an object; and demonstrates how powerful this tool is for whole vehicle modal survey, interactive design optimization, CAE model correlation, and nondestructive testing. Finally, areas for further development are suggested.

Integrated simulations of structural performance, molding process, and warpage for gas‐assisted injection‐molded parts. I. Analysis of part structural performance

Whether it is feasible to perform an integrated simulation for structural analysis, process simulation, as well as warpage calculation based on a unified CAE model for gas-assisted injection molding (GAIM) is a great concern. In the present study, numerical algorithms based on the same finite element mesh used for process simulation were developed to simulate the bending performance of gas-assisted injection-molded parts. Polystyrene and nylon plates designed with five different channel geometries were gas-assisted injection-molded. Part flexible strength was measured via bending tests. It was found that part stiffness basically increases linearly with the inertia moment of the plate. Gas channel design results in part structural reinforcement by introducing an additional moment of inertia determined by the shape and the dimension of the channel section as well as the hollowed-core geometry. An analysis algorithm based on VRT/DKT elements superimposed over beam elements representing gas channels of various section geometries was developed to evaluate part bending behavior. An equivalent diameter was assigned to the beam element so that both the original gas channel and the circular beam have the same moment of inertia. The simulated results were also verified with ANSYS 3-D and 2 ½-D analysis. The simulations show reasonable accuracy as compared with measured results and predictions from ANSYS. This investigation indicates that it may be feasible to achieve an integrated simulation for GAIM under one CAE model, resulting in great computational efficiency for industrial application. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 417–428, 1998

Integrated simulations of structural performance, molding process, and warpage for gas-assisted injection-molded parts. I. Analysis of part structural performance

Whether it is feasible to perform an integrated simulation for structural analysis, process simulation, as well as warpage calculation based on a unified CAE model for gas-assisted injection molding (GAIM) is a great concern. In the present study, numerical algorithms based on the same finite element mesh used for process simulation were developed to simulate the bending performance of gas-assisted injection-molded parts. Polystyrene and nylon plates designed with five different channel geometries were gas-assisted injection-molded. Part flexible strength was measured via bending tests. It was found that part stiffness basically increases linearly with the inertia moment of the plate. Gas channel design results in part structural reinforcement by introducing an additional moment of inertia determined by the shape and the dimension of the channel section as well as the hollowed-core geometry. An analysis algorithm based on VRT/DKT elements superimposed over beam elements representing gas channels of various section geometries was developed to evaluate part bending behavior. An equivalent diameter was assigned to the beam element so that both the original gas channel and the circular beam have the same moment of inertia. The simulated results were also verified with ANSYS 3-D and 2 ½-D analysis. The simulations show reasonable accuracy as compared with measured results and predictions from ANSYS. This investigation indicates that it may be feasible to achieve an integrated simulation for GAIM under one CAE model, resulting in great computational efficiency for industrial application. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 417–428, 1998

Finite-element modeling of the transient response of MEMS sensors

The finite-element method of analysis is unrestricted by size considerations and is well suited for the study of very small structures such as MEMS devices embedded in structures. This paper presents the numerical approach and results for a silicon-based micro-flow sensor for pulsed-flow sensing. The new approach presented here is the treatment of transient problems. A finite-element formulation is presented for modeling the dynamic response of piezoelectric ceramic sensors embedded in a micro-cantilever subjected to mechanical loading resulting from fluid flow. An unconditionally stable method (called the -method) is used for the direct integration of the equations of motion and implicit - explicit procedures are used for the transient analysis of the linear system of equations. For verification of the code, the device is tested for step, rectangular pulse and sinusoidal loading. For the case of the micro-fluid flow sensor, numerical results are in good agreement with the available experimental data based on a piezoresistive sensor. The numerical approach presented here may be used in CAE models for microsensors under more realistic, transient excitation.

Simulator training in anesthesia growing rapidly:CAE Model Born at Stanford

Only a few years ago, there were but two patient simulator centers in North America. Now the number is growing rapidly as simulator-based training in anesthesiology is evolving to more common part of resident and CME training. A number of centers focus on crisis management training because of the perception that it offers a high potential impact on practitioners' ability to offer optimal patient care. Many variations of the original ACRM training have emerged. Other target populations besides anesthesiologists for simulator-based training have been identified and curricula are in place or under development for these populations. As new centers adopt simulator-based training, they are likely to adopt existing curricula as well as to develop new ones for their own special needs and for expanding target populations. Mechanisms are now in place by which experienced centers can assist new ones in acquiring the expertise to begin their training activities.

Temperature Measurement in Heating Cylinder of an Injection Molding Machine

The effects of molding conditions, such as the set temperature of the band heaters and the screw rotation rate, on the temperature history and distribution in the heating cylinder have been studied by measuring the barrel temperature and the temperature at the screw surface. The temperature history at the screw surface during the molding process was measured by using a thermocouple telemetry system. The measured results were compared with the set temperatures of the heaters. Representative PP and PS resins were used in the experiments.The observed temperature distribution along the screw axis indicates a steep temperature rise at the feed zone, and it differs largely from the set values. The set temperature at the feed zone notably affects the temperature of the polymer melt in the compression and metering zones. The results obtained in this study will be useful for an optimum design of the heating cylinder and also for the construction of a CAE model.

Design and characterization of high performance 60 GHz pseudomorphic MODFET LNAs in CPW-technology based on accurate S-parameter and noise models

An accurate database for active and passive MMIC components valid up to millimeter-wave frequencies has been established. The CAE models for the transistors and the passive CPW-components; which include the coplanar T-junction, are derived from on-wafer S-parameter measurements up to 63 GHz. For noise modeling of the MODFETs up to millimeter-wave frequencies, an approach based on the temperature noise model reported by M.W. Pospiezalski (1989) has been used. The parameter T/sub d/, which is required for the temperature model, is extracted from on-wafer noise parameter measurements up to 18 GHz. Using this database, the authors have designed and fabricated low-noise V-band two-stage amplifiers, using pseudomorphic MODFETs on a GaAs substrate, which have a performance of 10.5-dB gain and 5.2-dB noise figure at 58.5 GHz. Very good agreement between simulated and measured MMIC gain and noise performance is achieved up to V-band.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>