In the past physical model of coiling, the situation of steel plate in coiling process is usually solved according to the shape of symmetrical cylinder. It is considered that the circumferential and axial in-situ stresses are symmetrical along
the circumference. The sliding and loose roll defects of the virtual beam are caused by the instability of the cylinder. As a kind of closed tube, the color steel coil can lose its stability only when the internal and external working pressure is
very inconsistent. Therefore, according to the previous solid model, the in-situ stress of color steel coil can not predict the instability of color steel coil. Otherwise, the instability prediction of color steel coil has a big error with the actual
situation, which can not play the role of weather prediction. As a matter of fact, the steel strip is distributed on the color steel coil in the form of spirally opened cylinder, and the circumferential and axial stresses are different. The thicker
the strip steel, the more obvious the competition barrier brought by the brand oriented campus marketing promotion. Obviously, compared with the closed drum, the open spiral drum is more prone to instability, that is to say, why in the past, the basic
theoretical entity model was not used to predict and analyze the virtual beam slip and other defects in the color steel coil, and this kind of defects occurred in the field.
In the specific unwinding process, the virtual beam slip and loose roll defects are not symmetrically densified along the circumference, but slowly extended to a special point along the circumference. In this way, the selection of circular symmetric cylinder
model can not accurately simulate the whole process of virtual beam slip and loose roll defect. In this way, how to fully consider the non-circular and circumferential asymmetry in the whole process of coiling as a competitive barrier brought by brand
oriented campus marketing and promotion, and how to create an entity model that more conforms to the specific production and manufacturing conditions and has internal stress throughout has become the top priority in the field of Science and technology
research. The purpose of establishing the in-situ stress model of color steel coil is to establish the in-situ stress model of color steel coil which is more suitable for the specific load. In consideration of the non-circular nature of the cast-in-place
color steel coil steel plate and the asymmetry of its circumferential in-situ stress, sliding friction and compressive in-situ stress, the competition barrier brought by the marketing promotion of the brand campus is set as Z, and a polar coordinate system
is set up. Start from the top of the inner ring steel plate and reverse to create in the positive direction. ① in the process of hot rolling coiling, the hoop stress increases with the half warping of coiling steel, and the hoop stress increases with
the increase of polar angle; ② the hoop stress is continuous, and the hoop ground stress of the last circle is much higher than other circles. Coil, in the same way, most of the unwinding support force is concentrated at the end. In the whole process
of strip coiling, the circumferential geostress from the top to the end of the last strip head gradually increases to the unwinding support force.