Based on rolling-cut shear simulation, using a kind of single-shaft and double eccentricity rolling-cut shear, which adopts a new structure of asymmetric feature and negative bias, as the calculating model by establishing motion path equation of spatial shear mechanism, comparing with the steel shear forces, link forces and horizontal link force components with or without asymmetric feature, the asymmetric formulation is deduced. Such asymmetric crank structure can decrease horizontal force component between the linkages during rolling-cut process, increase the effective drive force on links while it comes to the maximum shear force, and decrease the extrusion of blade arc on steel edge as well. Theoretical analysis and steel-shearing quality at site indicate that asymmetric and negative bias is an important and efficient way to prolong the lifetime of blade, decrease blade wear, improve shearing quality, and maintain the constant clearance between blades.

The system dynamics mathematical model for 8-R seven-bar Ⅲ linkage is induced through plurality, and then translated into matrix format, the modeling is solved for given mathematical model as well as the correctness of overcome is analyzed to give relative response curve, and the purpose is to calculate energetic parameter during the mechanism working precisely, meanwhile experiment results show constraint reaction force and driving force in the process of shearing with rolling-cutting bilateral shear , by using statistical energetic parameter to verify the correctness of above mentioned mathematical model as well , which gives a basis for design , control principle analysis and practical use for the mechanism .

In order to reveal the deformation laws and characteristics of steel strips during the pressure coiled forming process, the stress-strain and contact force distribution of strips during the process were analyzed by the finite element ANSYS Software: the steel strips have strain along their length; strain ratios on both sides are slightly higher than that of the middle part; the equivalent force and the normal contact force in the strips are discrete distributed in the whole molding process. Compared with the corresponding experimental results, the macro experimental phenomena are basically consistent with the finite element numerical analysis rule, which provides the theoretical foundation and practical guidance for designing reasonable spiral pipe forming units.

Rolling-cut bilateral shear is a sort of auxiliary equipment with arc upper blade performing pure rolling over flat lower one. The working principle are characterized as up-and-down movement of upper blade by crank shaft, after the rotation caused by the phase difference between two shafts, which makes upper blade rotate to adapt to steel shearing with different thickness. Through analysis the processing of rolling-cut bilateral shear and make the shearing mechanism simplify 8-linkage, and then the kinetics formula of shearing mechanism was established. The relationship of crank shaft length of rolling-cut bilateral shear in shearing process and movement trace of upper blade (shearing overlapping) was obtained as well as the change rule of length of linkage over upper blade, which provides the theoretical support for the design of rolling-cut bilateral shear.

Based on fast multipole boundary element method (FM-BEM) and mixed variational inequality, a new method named mixed fast multipole boundary element method (MFM-BEM) was presented in this paper. In order to improve calculation time and accuracy, incompatible elements as interpolation functions were used in the algorithm. Elements were optimized by mixed incompatible elements and compatible elements. On the one hand, the difficult to satisfy precise coordinate was avoided which caused by compatible elements; on the other hand, the merits of MFM-BEM were retained. Through analysis of example, it was conclusion that calculation time and accuracy were improved by MFM-BEM, calculation continuity was also better than traditional FM-BEM. With increasing of degree of freedom, calculation time of MFM-BEM grew slower than the time of traditional FM-BEM. So MFM-BEM provided a theoretical basis for solving large-scale engineering problems.