Life Predict and Simulation of the Copper Wire in Flexible Printed Circuit Board
Fatigue failure of the circuit board's research focuses on the influence to the circuit board of vibration of rigid circuit board type, distribution of Electronic Components on the board etc. And there is relatively little research to the flexible circuit board's fatigue life research. Local stress-strain method is used to predict the fatigue life. Simulate actual fatigue test load conditions to established finite element model of flexible printed circuit board. Perform fatigue analysis under the periodicity stress. Drawn fatigue life of copper wire in different loading conditions. There is guiding significance to the follow-up test.
Stress Distribution Analysis Between Single & Triple Hole PCB
Mostly a microcontroller is built onto a single Printed Circuit Board(PCB). This board serves as a platform for interconnection between electronic components and acts mechanically support.The Printed Circuit Board(PCB) experiences mechanical burden such as bending when subjected to man handling. In this paper, simulation of bending process on Printed Circuit Board(PCB) during depaneling was done. Ansys Version 11 software was used to study the stress response on the Printed Circuit Board(PCB) during bending process. Two 3D models Printed Circuit Board(PCB) were developed:one of the model with single through hole located near constrained area and other model with three single through hole located at top, center and near the constrained area. The stress response of the two models have been compared. From the simulation results, it showed that the value of stress response of the Printed Circuit Board(PCB) increases with increasing displacement height. The Printed Circuit Board(PCB) model with three single through hole demonstared higher stress compared to the Printed Circuit Board(PCB) model with single through hole. At displacement height of 5cm, the peak stress for both models were attained.
In search of optimum chest radiography techniques.
A nation-wide study of chest radiography in Sweden had previously revealed a large variation in the physical and technical factors involved, in particular the radiation dose. In this study the image quality could not be assessed unambiguously. The aim of the present study was to try to establish a correlation between visual grading of radiographs and physical and technical factors in order to find the optimum chest X-ray system. The physical and technical performance of 24 chest units was evaluated. Radiographs were taken of an anthropomorphic chest phantom supplied with test structures simulating various pathologies. Image quality was assessed by visual grading analysis of the radiographs. The physical and technical parameters of the units rated best were used to exemplify good radiographic practice. The results were in agreement with the recommendations issued by the Commission of the European Communities (CEC). It was also shown that low radiation dose is compatible with high-quality radiographic imaging of the chest.