Simulation Technologies for Mechanical Systems
Aiming for Compatibility between Performance and Reliability
Trends in Mechanical Simulation Technology
YOSHIDA Yuichiro / OZAWA Kaoru
Computer-aided engineering (CAE) is an essential information technology, supporting engineers in tasks such as research, development, and design of products and contributing to the shortening of development periods. With CAE now being widely used in the business sphere, the quality assurance of CAE and efforts to strengthen appropriate CAE processes are also required. Britainís National Agency for Finite Element Methods and Standards (NAFEMS) is taking the initiative in the quality assurance of CAE, and the American Society of Mechanical Engineers (ASME) and the Japan Society of Mechanical Engineers (JSME) have also started work in this area.
With this as a background, Toshiba has been promoting the quality assurance of CAE processes based on ISO 9001, and is making strong efforts to utilize the appropriate CAE processes for product development.
Structural Design of Mobile Electronic Products Using Large-Scale Stress Simulation
KAWAKAMI Takashi / YOSHIMURA Shinobu / AKIBA Hiroshi
Structural integrity design is of great importance to ensure the reliability of hardware products, and a large-scale stress simulation technology has recently become available for this purpose.
We have performed drop impact analysis of a fully assembled model of a cellular phone using ADVCTM, which is a commercial parallel structural analysis code based on the ADVENTURE system, and verified very good performance. In addition to improving the accuracy of structural integrity design, this large-scale stress simulation is expected to save labor and shorten the process of stress analysis for the structural design of hardware products.
Visualization of Turbine Blade Pressure Loss Characteristics by 3D Unsteady Flow Analysis
YOKONO Yasuyuki / BISWAS Debasish / NIIZEKI Yoshiki
Toshiba has performed numerical studies of three-dimensional (3D) incompressible viscous flow within a turbine cascade based on a high-order large eddy simulation (LES) approach, to visualize 3D unsteady flow for investigation of the pressure loss process.
Analysis was carried out for a wide range of inlet flow angles in the design and off-design conditions. The numerical simulation was able to reproduce and obtain good coincidence with the experimentally measured results of the occurrence of a sharp increase in pressure loss in the center of a turbine blade as the inlet flow angle shifted from the design flow angle. It was found that a leg of the horseshoe vortex produced in the leading-edge region was stretched toward the blade suction surface, and that the formation of a secondary vortex core in the trailing-edge wake region was the main cause of the pressure loss. By the reproduction of flows in off-design conditions, this numerical method is applicable to simulations of a wide range of design conditions.
Captured Image Simulation Technology for 198.5 nm Photomask Defect Inspection Tools
SHIRATSUCHI Masataka / HONGUH Yoshinori / HIRANO Ryoichi
Semiconductor manufacturing process technologies have been making progress in terms of nanofabrication in recent years. In particular, argon fluoride (ArF) excimer laser exposure tools and alternating phase shifting masks (alt-PSMs) are expected to be utilized in actual production. A feature of the alt-PSM is its three-dimensional (3D) structure to control the wavefront phase as well as amplitude of transmitted light. It is therefore essential to develop a highly precise photomask inspection method to check such newly developed photomasks.
In the development of optical setups suitable for inspecting these new types of photomasks, Toshiba has developed a captured image simulator with a vector model diffraction solver, which is able to appropriately support such 3D photomask structures and high-numerical-aperture (high-NA) magnifying optical systems.
Simulation Technology for Optimizing Component Design and Manufacturing Processes
Maintenance of quality and shortening of processing times are required in various component manufacturing processes such as resin molding, press processing, removal processing, adhesion, crystal growth, and so on. To meet these requirements, Toshiba has introduced a simulation technology for optimizing component design and manufacturing processes.
In the manufacturing process, for example, the optimization of double-sided polishing conditions to enhance the flatness of silicon (Si) wafers, and of the heating temperature profile of adhesive for connecting Si chips to printed circuit boards (PCBs) in flip-chip surface mounting technology, were realized using the newly developed simulation technology. In the design of components, not only functions and performance but also manufacturability must be taken into consideration. As an example of the application of our simulation technology, the design of PCBs was optimized in order to minimize PCB deformation in the reflow process by making use of the difference in thermal expansion between copper and PCB resin.
Crack Progress Simulation Analysis in Residual Stress Fields
ENDO Tetsuya / OHASHI Toshiki / OKUDA Yukihiko
In recent years, the need for assessment of the structural integrity of core shrouds with cracks due to stress corrosion cracking (SCC) on welded joints of core shrouds in boiling water reactor (BWR) plants is increasing.
The direction of crack propagation due to welding residual stress is known to change in a multiaxial stress field. In response to the demand for prediction of the propagation of cracks due to SCC, Toshiba has developed a multipurpose two-dimensional crack propagation analysis method that allows rapid evaluation, and a three-dimensional crack propagation analysis method for detailed evaluation of cracks having a complex shape.
Coupled Thermal-Stress Simulation Technology for Electronics Package Structures
HIROHATA Kenji / AOKI Hideo / NINOMIYA Ryoji
New high-density assembly technologies such as thinner printed circuit boards (PCBs) and narrow-pitch soldering are being applied to the production of compact digital equipment with high functionality. High reliability and ease of assembly are also required for these products in addition to high functionality. As a result of this trend, technologies for the analysis and evaluation of product failure phenomena due to complex problems related to heat and stress have become increasingly important.
Toshiba has developed a coupled thermal-stress simulation technology to predict the mechanisms of failure phenomena and improve the design and production processes. This technology realizes high-quality design by considering both manufacturability and reliability at the first stage of development.
Numerical Simulation of Mixed Lubrication for Air-Conditioner Rotary Compressor Mechanisms
ITO Yasutaka / HATTORI Hitoshi / MIURA Kazuhiko
Reducing the friction loss of the compression mechanism is of key importance in improving the efficiency of air-conditioner compressors.
Toshiba has developed a technology for the numerical analysis of mixed lubrication. This technology is useful for reducing the friction loss and improving the efficiency of rotary compressors in air conditioners. In this analysis, the modified Reynolds equation and the elastic contact equation, taking the effect of surface roughness into consideration, are solved as a coupled problem. The breakdown of a lubrication oil film and occurrence of solid contact can be predicted by this analysis. In addition, a mechanical design that minimizes friction loss can be realized. We have applied this analysis to the vane sliding surface, which is one of the main sliding parts in rotary compressor mechanisms. The effects of the design parameters on the friction loss were clarified by simulation.
Simulation Technology for Virtual Control Firmware Testing
YOSHIDA Mitsunobu / KONDO Koichi / MOTOHASHI Shoichi
With the scale of firmware in electromechanical products continuing to increase year by year, the shortening of overall development times with quality assurance is one of the highest priorities of firmware development.
Toshiba is promoting "virtual firmware testing" using a mechanical simulator in the upstream development process. The key feature of this mechanical simulator for control firmware is both simplicity and reusability of the simulation model, rather than precision of the simulation model. To meet these requirements, in cooperation with InterDesign Technologies, Inc. we have developed a dynamics simulation modeling language, DCMLTM(Dynamics Constraint Modeling Language), and have been applying it to the VmechTM virtual mechatronics simulator.