Dynamic Response Analyses of Plastic Greenhouse Structure considering Fluctuating Wind Load

Abstract

Wind load is one of the main factors of plastic greenhouse collapse. To solve the dynamic response problem of greenhouses under wind load and determine the dangerous section of a skeleton structure, the investigated lump method is presented for the dynamic response analysis of a plastic greenhouse, considering pulsating wind on the basis of Timoshenko beam theory. First, the investigated lump is designed according to the Timoshenko beam microbody concept. On the basis of Timoshenko beam theory, the governing equations of the skeleton structure of the greenhouse are derived, and the realization process of the algorithm is also provided. Second, the accuracy and effectiveness of the proposed numerical method are verified by an example in which the bending wave of a variable cross section beam with free ends propagates. Finally, the dynamic response of the steel skeletons of plastic greenhouses is analyzed under the effect of the simulation wind speed, and the spatial distribution of the maximum node displacement and the section maximum stress of the steel skeleton are obtained. Computational results show that the displacement peak is near the top of the plastic greenhouse. The most dangerous section of the top chord in the steel skeleton is near the leeward bottom, which has a maximum stress of 219.4 MPa, and the most dangerous section of the bottom chord is near the 1 m height on the leeward side of the plastic greenhouse, which has a maximum stress of 248.5 MPa. Bending stress is the main factor of the rapid increase of stress at the bottom of the skeleton. The maximum node displacement and cross-sectional stress caused by fluctuating wind loads are higher than those caused by average wind loads. The fluctuating wind load should be considered in the wind-induced response analyses of plastic greenhouses.

Study of Wind Field and Surface Wind Pressure of Solar Greenhouse Group under Valley Topography Conditions

“…The value of gravitational acceleration is closely related to latitude and altitude. The gravitational acceleration at an altitude of 0 m at a certain latitude can be obtained from Equation (3). Then, the resulting value can be corrected for altitude using Equation ( 4) to obtain the value of gravity, taking latitude and altitude into account [32].…”

“…The solar greenhouse framework is distinguished by its lightweight construction; expansive span; and elongated, slender poles, collectively constituting a flexible structural paradigm. Furthermore, the roofing materials employed in solar greenhouses are characterized by their lightweight nature and susceptibility to wind dynamics [2,3]. Incidents of high winds causing damage to solar greenhouse roofs and their supporting structures have intermittently occurred, leading to substantial economic losses and disruptions in normal production.…”

A new greenhouse: an attempt to reduce the cost of growing plants

“…In addition, a PVC mini greenhouse can be easily folded [12][13]. On the other hand, the impact of wind load on the mini greenhouse should not reduce its stability [14][15]. So, the stiffeners are added.…”

Dynamic response analysis of a whole steel frame solar greenhouse under wind loads

“…Using a large-sized wind tunnel, the wind pressure distribution and local damage of a large-span circular arch greenhouse built in coastal areas were studied 9 . It is suggested that the damage caused by the bending moment due to a strong wind load should be considered in the calculation of the wind pressure coefficient in structural design 10 . Briassoulis et al 11 established a three-dimensional structure model and a two-position frame model of a large multi-span circular arch greenhouse.…”

“…The dynamic response mechanism of greenhouse structures under dynamic loads needs further theoretical research. In our previous work, a block method was proposed for the dynamic response analysis of a solar greenhouse with a plane rigid frame model under wind load 13 . The wind-induced vibration responses of a 12 m span truss solar greenhouse were also investigated by the time domain method 14 .…”