Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
As a common structural form, space structure is widely used in all kinds of construction projects. It has various demands on steel, which are analysed in the following dimensions: strength, toughness, weldability, corrosion resistance, specification and quality of steel.
(1) Yield strength and tensile strength
Space structures need to withstand a variety of loads, such as self-weight, wind loads, snow loads. The yield strength and tensile strength of steel are key indicators. Sufficient yield strength ensures that the structure does not deform excessively during normal use, while tensile strength ensures that the structure does not fracture under extreme loads. For example, in the space structure of large stadiums, the selection of steel with high yield strength and tensile strength can ensure the safety of the structure when it is subjected to large wind loads and crowd loads.
(2) Uniformity of strength
The uniformity of strength of steel is also very important. Uneven strength may lead to local stress concentration, so that the structure in the use of the process of early destruction.
(1) Impact Toughness
At different ambient temperatures, space structures may be subject to impact loads. Steel should have good impact toughness to prevent brittle fracture under severe conditions such as low temperature. Especially in buildings in cold regions, the impact toughness of steel is required to be higher.
(2) Fatigue toughness
Space structures are subject to repeated loading effects, such as repeated stresses caused by wind vibration, during long-term use. This requires the steel to have good fatigue toughness, able to resist the generation and expansion of fatigue cracks. For example, in coastal areas, often affected by typhoons, space structures, the fatigue toughness of steel is critical to the long-term safety of the structure.
(1) Weldability
The rod connections of space structures are usually welded, so the weldability of steel is an important index. Steel with good weldability is not easy to produce cracks, porosity and other defects during welding, and can ensure that the strength and toughness of welded joints are comparable to that of the base material. For example, in the field installation of space structure, the welding quality directly affects the safety and stability of the whole structure.
(2) Welding process adaptability
Different space structures may use different welding processes, such as manual arc welding, gas shielded welding and so on. The steel should be able to adapt to these different welding processes to ensure the stability of welding quality.
(1) Natural Environment Corrosion
Exposed to the natural environment, the space structure will be affected by the atmosphere, rain, humidity and other factors, and is prone to corrosion. Steel should have a certain degree of corrosion resistance to extend the service life of the structure. For example, space structures at the seashore require higher corrosion resistance of steel due to salt in the air.
(2) Adaptability of anti-corrosion measures
In order to improve the corrosion resistance of steel, some anti-corrosion measures are usually taken, such as applying anti-corrosion paint and hot-dip galvanising. Steel should be able to adapt to these anti-corrosion measures to ensure the durability of the anti-corrosion effect.
(1) Specification Requirements
The rods and nodes of space structure have strict requirements on the specification of steel. The cross-section shape and dimensional accuracy of steel should meet the design requirements to ensure the assembly accuracy and stress performance of the structure. For example, the dimensional deviation of the diameter and wall thickness of the rods should be controlled within the permissible range.
(2) Quality stability
The quality stability of steel is the basis for ensuring the quality of space structure. The manufacturer should have a perfect quality control system to ensure that the quality of each batch of steel meets the standard requirements. At the same time, in the process of transport and storage of steel, appropriate measures should also be taken to prevent the steel from being damaged and contaminated.
