Aiming

In the process of research and development of tube bending forming technology, the way of improving the forming quality and establishing the optimization of forming process parameters has become an important problem that should be solved quickly. This text simulated the process of bend forming with the way of finite element, combined with the effects of geometric and physical parameters on the forming quality of bending pipe, taking the important parameters which are measurements of the pipe wall thickness variation as test indexes, made the virtual orthogonal experiment and gained the laws of the bending angle, relative bending radius, relative wall thickness, thrust, pipe friction coefficient between mode have effects on the forming quality of wall thinning rate and wall thickening. Through the comprehensive analysis and additional test, obtained the optimal parameters values, improved the accuracy of simulation and the optimization results of orthogonal test, improved the quality of tube bending forming.

Abstract

In this paper, we present a model for the noise in narrow-band power line communication. We first derive a statistic model for the distribution of noise in a narrowband power line. The noise consists of three parts such as impulse noise, background noise, and narrow-band interference. For each part, we analyze its characteristics with the Markov Chain Monte Carlo (MCMC) method. The model is evaluated with extensive field measurement data and compared with a classical noise model. The evaluation results show that the proposed model can approximate the noise in narrow-band power line more accurately.