Computer simulation of the rotary cutting edges with helical teeth on the complex surfaces
this paper researched the forming theory of the cutting tools with helical teeth and complex surfaces. Deduced the nonlinear equations of the movement of NC system to generate such tools, presented the way to find the solution of the equations, calculated the cross section graphics of the teeth profile and computer simulation of NC machining.
A feature-based parametric modeling system for CAD/CAPP/CAM integrated system
For shortening the product development time, this paper proposes a feature based parametric product modeling system, called ZD-MCADII, which is suitable for the integrated engineering design in CIM system environment. The architecture of ZD-MCADII and the characteristics of its modules are described in detail. The ZD-MCADII product data is managed by an object-oriented database management system OSCAR, and the product model is built according to the standard STEP. As the product design is established on a unified product model, all product data are globally associated in ZD-MCADII. ZD-MCADII provides various design features to facilitate the product design, and supports the integrity of CAD, CAPP and CAM.
Experimental study on bond behavior between high-strength grout and deformed steel bars
Abstract Engineers use high-strength grout to connect precast concrete members for its low shrinkage and good fluidity. This paper designed 87 central pull-out specimens using the control variable method to investigate the influence of factors on the rebar-grout bond property such as compressive strength, steel grade, bar diameter, transverse stirrups, and bond length. The test result showed that improving grout compressive strength (85.8 MPa–122.7 MPa) cannot improve the bond strength, which was different from the previous conclusions of concrete pull-out tests. Simplified formulas were presented for calculating the characteristic values of bond strength, residual strength, peak slip, and relative slip of load-holding platform based on parameter analysis. Then, a constitutive model was proposed to predict the full-range bond stress-slip curve of high-strength grout and steel bar specimens from bearing to failure. Finally, FEA models were established to evaluate the applicability and accuracy of the constitutive model.