Structural Dynamics Analysis of Three-Dimensional Bi-Axial Sun-Tracking System Structure Determined by Numerical Modal Analysis

Abstract

Sun-tracking system (STS) is a key factor for solar photovoltaic (PV) future and new answers for the solar market. It will expand large-scale PV projects (PV farms) worldwide, and it is possible to collect more energy from the sun. PV farms consist of thousands of STS that are subject to dynamic loads (wind, snow, etc.), vibrations, and gravitational loads. This paper presents the structural dynamic analysis of a 24 m2 bi-axial STS (azimuth-elevation) at different elevation angles based on its modal parameters (natural frequencies, modal shapes, and modal damping ratios) and dynamic performance indices (modal participation factors (MPF), forcing frequencies, and mechanical quality factors) by means of the finite element analysis (FEA). The simulation results show that the structural dynamic design of the STS meets the desired structural requirements and agrees well with structural dynamic standards (EN 1991-1-4 and ASHRAE). These results can be used for further analysis on optimal design and vibration safety verification for the bi-axial STS (PV applications).

Numerical modal analysis of a 850 KW wind turbine steel tower

“…where X, Y and Z are the principal directions of the structure, N is the number of the modes, m x , m y and m z is the mass in its direction and p is the vibration mode taken under consideration. Several FE Codes require that a minimum 90 percent of the total structure mass in the calculation of response for each principal direction of the participating mass can be considered enough to capture the dominant dynamic response of the structure [9,53]. In this study, it would require the calculation of 50 modes to obtain the 90% mass participation.…”

“…The first can be divided into two types, a dynamic response and a quasi-static. The dynamic response of a wind turbine may be characterized by its modal parameters (natural frequencies, damping characteristics and mode shapes) [8,9]. Modal analysis has the ability to determine these parameters allowing the tracking of small changes in these parameters over time.…”

“…Modal analysis has the ability to determine these parameters allowing the tracking of small changes in these parameters over time. These changes may originate from characteristics of the loads, changes in mass distribution or damage to the structure [9][10][11][12].…”

Numerical simulations on static and dynamic response of full-scale mast structures for H-Darrieus wind turbine

“…Subjected to nature's forces (winds, cold or extreme heat, sand, and earthquakes), gravitational loading varies with time as the turbine operates. To enable WT structures to operate in any external conditions and to ensure their expected service lifetime, each component of the WT has to be designed adequately, safely operated, and manufactured with suitable quality (Ferroudji et al, 2018;So¨ker, 2013). There are a number of guidelines that show the existing state of the art related to the design requirements of WTs and their key components such as the International Electrotechnical Commission standard IEC 61400-x Series.…”