Hiroo Sakamoto

Structural Design for Racks of Photovoltaic Array

Photovoltaic power generation (PV) for commercial use is installed in the building roof of communal facilities and industrial facilities, and remarkable growth in the future is foreseen. PV panels and mounting racks are affected by loads of wind, snow and earthquake etc, so it is important to the strength design that considers reliability. In this study, we were particularly focused on PV panel mounting racks (PV rack) for flat roof. We obtained wind loads to PV racks for flat roof from wind tunnel tests with scale model, and also quantified the strength reduction of the fastening part by screws from bending tests of steel, and proposed the strength design guideline of wind load. In addition, we studied structural design optimization for PV racks for flat roof, as a result, a new structure of rack for flat roof was obtained for achieving high reliability and low cost.

Strategic Scheme for Identifying Specification of Structural Design Optimization

Structural design optimization has become an effective paradigm for designing and developing various kinds of products. However, it is not so popular in the electric appliances in spite of their small sizes and relatively simple configurations. This paper first reviews the reason why the paradigm is difficult to be utilized in designing and developing electric appliances based on the individual but practical experiences in utilizing computational design approaches such as CAE-based design and optimization based design methods. It reveals that the identification of design specifications is fairly important as their prerequisites in the field of electric appliances. Then this paper proposes a strategic scheme for systematically identifying specifications for structural design optimization by transforming the frameworks of design-for-X (dfX) methodologies to the direction. The scheme is composed of Specification Priority Matrix (SPM), for identifying the antipathetic importance of performance, cost, time and reliability, Failure Mode and Condition Specification (FMCS), for extracting, categorizing and identifying failure modes and their critical ones, Design Approach Tree (DAT), for selecting an appropriate design approach based on the result of SPM and FMCS, etc. Finally, its effectiveness and validity are discussed by studying the past design and development cases.