Designing electrodynamic loudspeakers by using a new computer modeling scheme

Additive manufacturing has opened the door to the creation of lightweight lattice structures. However, present Computer-Aided Design (CAD) and Computer-Aided Engineering (CAE) software are unsuitable for these types of structures. The objective of this research is to examine the performances of current CAD and CAE software to design lattice structures and to demonstrate their limitations and propose requirements for future developments. A performance evaluation of a case study for lattice structure designs was conducted. The criteria used for the evaluation were CAD human-machine-interface, RAM consumption, data exchange between CAD, CAE and CAM tools and finite element analysis (FEA) duration and file sizes. The CAD tool was incapable of executing a repetition function for octet-truss lattice structures of 150 x 150 x 150 mm dimensions or larger and the software stopped working. For 70 × 70 × 70 mm octet-truss lattice structure, the FEA computation file size reached 36.6 GB. The CAD file size of a 200 x 200 x 200 mm octet-truss lattice structure reached nearly 290 MB. In conclusion, this study exposes the performance inadequacy of current CAD and CAE tools and CAD file formats to design lattice structures for additive manufacturing parts.

Searching and handling geometric data are basic requirements of any Computer Aided Engineering application (CAE). Spatial search and local search has greater importance in CAD and CAE applications for reducing the model preparation time. There are many efficient algorithms being made to search geometrical data. Current neighbour search strategy is limited and not efficient in different CAE platforms. R-tree is tree data structure used for spatial access methods. This paper presents a review of R-tree data structure with its implementation in one of the CAE tool for neighbour search and local search. It satisfies current neighbour search requirements in CAE tools. Results shows considerable amount of time saving compared to the conventional approach. This work concludes that R-tree implementation can be helpful in identifying neighbour part and reducing model preparation time in CAD and CAE tools.

Field programmable gate array (FPGA) devices, heavily used in spacecraft electronics, have grown substantially in size over the past few years, causing designers to work at a higher conceptual level, with computer aided engineering (CAE) tools synthesizing and optimizing the logic from a description. It is shown that the use of commercial-off-the-shelf (COTS) CAE tools can produce unreliable circuit designs when the device is used in a radiation environment and a flip-flop is upset. At a lower level, software can be used to improve the SEU performance of a flip-flop, exploiting the configurable nature of FPGA technology and on-chip delay, parasitic resistive, and capacitive circuit elements.

We present a newly developed computer aided engineering (CAE) tool for the design of capacitative micromachined sound and ultrasound transducers. The numerical scheme is based on the finite element (FE) method and takes all relevant nonlinearities (geometric nonlinearity of the mechanical structures, electrostatic force, moving body in an electrostatic field) and couplings between the different physical fields (electrostatic, mechanical and acoustical fields) into account. The applicability of the CAE tool is demonstrated by two practical examples: mechanical and acoustic crosstalk in capacitative micromachined ultrasound transducers (CMUTs) and total harmonic distortion of micromachined silicon microphones.

The Development of Computer Models for Ergonomic Accommodation

This article is going to contemplate the steps involved in the conception of an AC/DC integrated converter with the power factor correction (PFC) stage applied in an Organic Light-Emitting Diode (OLED) driver. An approach about converter design with emphasis in magnetic elements will be performed, such approach includes the support and design validation by computer-aided engineering (CAE). The obtained results show the viability of using CAE tools in power converters concept being useful for the power electronics designers that is looking to optimize their projects.

In the last decade, many industries introduced the Computer-Aided-Engineering (CAE) tools in order to decrease the number of prototype builds and to speed up the time of the development cycle. Although such analytical tools are relatively inexpensive to use and faster to implement as compared to the costly traditional testing design process; however, there are many variables that CAE tools cannot adequately consider, such as manufacturing processes, assembly, material anisotropy, and residual stresses. Therefore, still smart testing is required to validate the CAE results.

In the past decade, the mechanical engineering industry has searched for a design methodology that could systematically unify the support of computer-aided engineering (CAE) tools for the design process. More recently, some propositions have been put forward for the CAE-driven design process (CDDP), but the efficiency of these design processes is questionable. We have proposed improvements and new arrangements that result in the integrative CDDP (ICDDP), which makes CDDP more reliable, efficient and predictive. The ICDDP redefines the role of CAE tools and positions the optimization technology as a fundamental driving force behind the whole design process. Consequently, the ICDDP orders design phases as: (1) conceptual design, (2) design crystallization and (3) design sophistication, which steer the design process sequentially. The accurately established linkages between the sequential design steps enhance the smooth recurrence of the ICDDP for new product executions. In addition, this work demonstrates the application of the conceptual design phase to design a new L7e (eQuad) vehicle structure. This phase of the ICDDP illustrates the specific steering methodology for the topology optimization of a new eQuad structure as well as the geometric solution derivation step that reveals the transformation of bionic shapes into rough manufacturable geometry. Additionally, the numerical verification of the simple geometric model is presented for the load cases given. Our results exemplify the fact that the ICDDP allows engineers to design new innovative and lightweight structures.

Rubber isolators are mounted between a cooling module and a carrier to isolate the car body from vibration due to the rotation of the cooling fan. The isolators should be durable against fatigue loads originating from fan rotation and road disturbance. Thus, the design of rubber isolators is required to maximize both vibration isolation and fatigue life. In this study, the shapes of the rubber isolators are optimally designed using a process integration and design optimization (PIDO) tool that integrates the various computer-aided engineering (CAE) tools necessary for vibration and fatigue analyses, automates the analysis procedure and optimizes the design solution. In this study, we use CAE models correlated to the experimental results. A regression-based sequential approximate optimizer incorporating Process Integration, Automation and Optimization (PIAnO), a commercial PIDO tool, is employed to handle numerically noisy responses with respect to the variation in design variables. Using the analysis and design procedure established in this study, we successfully obtained the optimal shapes of the rubber isolators in two different cooling modules; these shapes clearly have better vibration isolation capability and fatigue lives than those of the baseline designs used in industry.

A method for optimal material selection aided with decision making theory

A recently developed calculation scheme for the numerical computation of the load‐controlled acoustic noise of power transformers is presented. This modeling scheme allows the precise and efficient computation of the coupled electromagnetic, mechanical and acoustic fields. The equations are solved using the finite element method (FEM) as well as the boundary element method (BEM), resulting in a separation of the acoustic‐magnetomechanical calculation of the winding vibrations resp. the acoustic‐mechanical computation of the tank vibrations (using FEM) and the calculation of the acoustic free‐field radiation (using BEM). The validity of the computer simulations has been verified by means of appropriate measurements. Simulated and measured values for winding and tank surface vibrations as well as the sound power level of the loaded transformer are found to be in good agreement.

Large-capacity power electronics in the range of MW or more has large physical dimensions, heavy weight and high power dissipation although the efficiency is high enough. These features sometimes put difficulties into the development only by the hardware prototypes. Then, CAE (Computer Aided Engineering) technology is now going to be applied to overcome some of difficult and complicated designs of parasitic inductance, thermal performance, mechanical strength and so on. The paper summarized trend of CAE technology application by introducing actual examples. The simulation results of CAE tools are evaluated by experiments with actual prototypes. In summary, the CAE technology of these days is found contributing effectively to the development process of large-capacity power electronics equipment.

In this study, computer aided technology was utilized to improve the traditional grid shoulder mortise-and-tenon joint (GSMTJ). Firstly, the traditional GSMTJ was redesigned through using separated loose tenon by the computer aided design (CAD) software called AutoCAD. And then the mechanical strengths of the traditional GSMTJs and the improved GSMTJs were compared and analyzed using the experimentally validated finite element method (FEM) based on the computer aided engineering (CAE) software called ABAQUS. Finally, the GSMTJs were further investigated from perspective of manufacturing efficiency using the computer aided manufacturing (CAM) software called JDSoft SurfMill. Based on the above simulation analysis, the improved GSMTJ was validated to be equivalent strength, high manufacturing efficiency increasing by 11.5%, low processing load ratio decreasing by 30%, as well as less wood material cost reducing by 3.6% compared with the traditional GSMTJ. The proposed improved GSMTJ was validated to be more suitable to modern wood processing machines. In addition, the methodology of combining the CAD, CAE, and CAM to wood products design was proofed efficient, economic, and feasible, and can be also used in design of other products.

Critical analysis of tools for computer-aided software engineering

FEM calculation of an acoustic field in a sonochemical reactor