Straightening Process Simulation Of Rebar Straightener With Rotary Huband Parameters Study

With the rapid development of national economy and the continuous extension of construction industry, the demand of rebar is becoming more and more in people’s daily life, at the same time, the quality requirements of rebar are higher and higher.Due to the diameter of rebar is small, limited to the process of production,rebars are usually supplied to the most of users in the form of plate roll after they are produced. In order to eliminate the bending and get flat rebars,they must be straightened before using.Straightener with rotary hub has its unique advantages,such as high straightening precision,stable straightening quality,and so on, especially suitable for the straightening of plate roll rebars.Its straightening performance is mainly depends on the the screwdown situation of straightening modes inside the hub. Current straightener with rotary hub is far less than the actual production needs, parameters such as the pitch of straightening modes are unreasonably designed,the screwdown adjustment of straightening modes also mainly relies on the opertaing experience of workers,without levels to be followed, leding a lot of inconvenience to the actual straightening,also reducing the production efficiency.This thesis takes the straightener with rotary hub as the research object, based on elastic-plastic bending theory of the metal bars with circular cross section, analyzes in elastic-plastic bending stress, curvature and bending moment of rebars;mechanical model of straightening system is set up, the design and calculation of straightening parameters such as the total number of straightening modes,pitch, amount of screwdown are completed.The three-dimensional finite element model of rebar straightening system with rotary hub is established,the straightening process of rebar is simulated dynamicly by the using of ANSYS/LS-DYNA software,the change of stress and strain in the straightening process of rotary hub straightener with straightening modes are got, the relevant theories of rotary hub straightening are verified.By virtue of the surface residual stress of the straightened rebar and the straightness accuracy,the straightening quality of rebar is evaluated.By the orthogonal test and straightening simulation, the influence laws of pitch, pres- sure parameters for the quality of the rebar straightening are got, as well as the influencing order degree and the best combination of straightening parameters;based on the optimal parameters combination, the rebar straightening quality is improved by adjusting the parameters appropriately;the influence laws of pinch roll traction on the quality of the rebar straightening are also confirmed.These provide the theory reference for the design and development of rotary hub straightener,as well as the actual straightening, having certain practical value and a certain guiding significance.