Advanced Materials Research Vols. 971-973

Abstract: In order to solve the problem in calculating the analytic equation of intersecting line which forms by two curved pipes, this paper presents a solution which based on UG. By employing UG we can extract the coordinates of discrete points of the intersecting line, then fit the discrete points with cubic B-spline curve, thus obtain the analytic equation. Finally, this paper verifies the feasibility of this method through simulation in Matlab, therefore, lays the theoretical basis for the development of flame cutting machine.

Abstract: With the widespread use of the Surface Mount Technology (SMT) in electronics assembly, the efficiency of SMT production line is the most important to increase the number of products quickly, enhance the market share and competitive strength. And the key point of efficiency improvement for SMT production line is the reasonable component distribution in chip mounter. In this paper, for a widely used SMT production line, its mathematical model of component distribution for two chip mounters was established. By identifying the model constrains and processing of the mathematical model, then the mathematical model was solved through Particle Swarm Optimization (PSO) based on natural selection with MATLAB. By contrast with the MATLAB function-bintprog solving, the results by PSO based on natural selection needs less iteration and short time, and the optimal component distribution program was efficiently obtained.

Abstract: The thermal state of the cylinder head has a huge influence on its fatigue and damage situation; therefore it is essential to accurately simulate the thermal state of the cylinder head during engine operation. In this paper, a method research of the cylinder head thermal state simulation test has been done. A thermal state simulation test bench has been launched, using induction heating and water-cooling to regulate the temperature. A series of cylinder head surface temperature field simulation tests has been accomplished. Compared to the actual engine test results, the temperature simulation results have an average error of less than 5% and a maximum error of 8.5% in these temperature test points. It turns out that the test bench can simulate the actual cylinder head temperature distribution accurately and will has significant effects on the research of the cylinder head thermal stress distribution and thermal fatigue situation.

Abstract: By analyzing the problems of leakage measurement methods of coupling clamps for aircraft tubing, a new technical solution is proposed based on the gas-liquid volume equivalent replacement principle. The test prototype and dedicated measuring device are developed. The results show that the new measurement method is scientific, safe, reliable and with high accuracy. The measurement method has already been used in the production of various coupling clamps in aircraft tubing.

Abstract: This paper takes a passenger car back door as an example with the use of glass fiber reinforced PET to replace steel. The sampling space is sampled by the optimal Latin hypercube experimental method and according to the experimental data, it establishes the polynomial response surface (RSM) model. Select NSGA −∏ genetic algorithm to optimize the back door assembly thickness of multi-objection with the purpose of lightweight.

Abstract: The relationship among the thermal parameters of supercharging system of internal combustion engine is very complicated. They affect and constrain each other. It is comparatively difficult to find out their changing rules and interactions, let alone the special supercharging system of natural gas engine. This paper is aimed to calculate and find out the internal connections among all parameters by rationally selecting parameters collected from experiences and establishing mathematical model for the supercharging thermal parameters of natural gas engine based on diesel engine’s supercharging estimation method, so as to provide theoretical basis for matching the supercharging system.

Abstract: The external characteristic curve of engine is the basis of choosing engine, matching and optimizing dynamic performance correctly. At present, most models of the external characteristic curve of engine are carried out by using polynomial regression equation for fitting the external characteristic curve of engine. In this paper, an establishing model method of the external characteristic curve of engine based on F distribution testing is proposed. F test with variance analysis is implemented for obtaining the difference of square sum of return difference between the former equation and the latter equation. If the test doesn’t go through, it can rise one level automatically, until the difference about square sum of return difference of the before-after fitting equation is no significant can it stop. This method provides a theoretical criterion for establishing model of the external characteristic curve of engine. When it is applied to the engineering case, the model will have a higher fitting precision.

Abstract: Aiming at the limitation by the high cost of test and length cycle process of the CNC grinding machine reliability evaluation, this article adopted small sample technology which needs less data while getting higher evaluation accuracy, by using the theory of Bayes theorem and failure rate as of the random variables, the experiment data of tracking CNC grinding machine for a year is analyzed. Results indicate that results acquired by this mean are consistent with the actual; meanwhile, it shortens test cycle and reduces cost, which is a very effective way to analysis CNC grinding machine. Therefore, it’s very essential that the small sample technology research is applied in the CNC grinding machine evaluation.

Abstract: Rubber bladder hydroforming is one of the most important technology in the aircraft manufacturing industry.The springback seriously restricted the one-step forming.This paper is a research on the springback angle of straight edge bending and curved edge bending by using FEM software PAM-STAMP2G .Comparing the angles between the straight edge bending and the curved edge bending to get the springback regularity along the circumference.The springback angle of the curved edge bending changes along the circumference closing to a parabola and the springback angle of the edge is approaching to that of straight edge bending.

Abstract: For the problem of rolling bearing mechanical fault detection, this paper proposed a fault detection method based on wavelet packet energy spectrum and partial least squares (PLS). Firstly, the collected vibration signal was decomposed by wavelet packet into independent frequency bands. The different frequencies energy spectrum could be collected from the independent frequency bands. That means the energy spectrum feature vectors whose changes reflect the running state could be constructed. Then analyze the energy spectrum feature vector by PLS, and establish the fault detection model. The fault could be detected by the T² and SPE statistics. Finally, the experimental results showed that the method is feasible and effective.