In extreme temperature environments, the thermal expansion and contraction effect of photovoltaic steel structures is a key factor affecting their structural stability.
In extreme temperature environments such as high temperature and high cold, photovoltaic steel structures will produce significant dimensional changes and internal stresses due to thermal expansion and contraction. If these changes are not effectively controlled, they will threaten the stability of the structure and even cause safety hazards such as deformation and cracking, affecting the normal operation and service life of photovoltaic power stations. Therefore, it is crucial to study the impact of thermal expansion and contraction effects on the stability of photovoltaic steel structures.
Materials have the characteristics of thermal expansion and contraction, and steel is no exception. When the temperature rises, the thermal motion of atoms inside the steel intensifies, the atomic spacing increases, and the volume of the steel expands; conversely, when the temperature decreases, the atomic spacing decreases, and the volume of the steel shrinks. This dimensional change is related to the temperature change and the linear expansion coefficient of the steel. Usually, the linear expansion coefficient of steel is about 1.2×10⁻⁵/℃. For large photovoltaic steel structures, even if the temperature change is small, the resulting expansion and contraction deformation cannot be ignored due to the large size of the structure.
Thermal expansion and contraction will affect all parts of photovoltaic steel structure. For photovoltaic bracket beams and columns, expansion or contraction will change the length of the components. If no expansion space is reserved during structural design, huge temperature stress will be generated inside the components. This stress may exceed the yield strength of steel, causing deformation such as bending and twisting of the components. For bolted connection parts, thermal expansion and contraction will change the preload of the bolts, causing loose connections and reducing the overall stability of the structure. In addition, cracks may occur at welds due to concentrated temperature stress, affecting the bearing capacity of the steel structure.
In high temperature environments, the thermal expansion effect of photovoltaic steel structures is more obvious. When exposed to high temperatures for a long time, the mechanical properties of steel will change, and its strength and elastic modulus will decrease. At this time, the temperature stress generated by thermal expansion is superimposed on the load stress of the structure itself, which may cause the local stress of the steel structure to exceed the ultimate strength of the material and cause structural damage. For example, in high temperature areas such as deserts, the surface temperature of steel at noon in summer can reach above 60°C. If the photovoltaic steel structure does not take effective temperature stress release measures, it is very easy to deform and damage.
In extreme low temperature environments, the shrinkage effect of photovoltaic steel structures also poses severe challenges. Low temperatures can reduce the toughness of steel, increase its brittleness, and produce cold brittleness. When the temperature stress caused by cold shrinkage of steel structures works together with other load stresses, the structure may suddenly fracture brittlely without obvious deformation. In cold high-latitude or high-altitude areas, the winter temperature can be as low as -30℃ or even lower, and the risk of cold shrinkage deformation and cold brittleness of photovoltaic steel structures increases significantly, seriously threatening the safety of the structure.
In order to reduce the impact of thermal expansion and contraction on the stability of photovoltaic steel structures, a variety of measures can be taken. In the structural design stage, expansion joints should be reasonably set to allow the steel structure to expand and contract freely when the temperature changes and release temperature stress; optimize the design of connection nodes and adopt flexible connection methods, such as using elastic gaskets and adjustable bolts, to alleviate the stress concentration caused by thermal expansion and contraction. In terms of material selection, steel with a small linear expansion coefficient or composite structural materials can be selected to reduce the impact of temperature changes on the structure. In addition, by real-time monitoring of the temperature and deformation of the steel structure, potential risks can be discovered in time and corresponding maintenance measures can be taken.
In extreme temperature environments, the thermal expansion and contraction effects of photovoltaic steel structures will have many impacts on their structural stability. From component deformation to material performance changes, from strength reduction at high temperatures to cold brittleness risks at low temperatures, all need to be fully considered during the design, construction and operation and maintenance stages. Through reasonable structural design, material selection and monitoring and maintenance measures, the thermal expansion and contraction effects can be effectively dealt with, the stability and safety of photovoltaic steel structures in extreme temperature environments can be guaranteed, and a solid foundation can be provided for the long-term and reliable operation of photovoltaic power stations.
