Research Of Strength And Fatigue Life For Notebook PC Hinge

Notebook PC hinge is an important part to connect laptop display and the system body,to evaluate hinge design is good or bad,there are two important technical indicators: the structure strength and fatigue life.Higher strength hinge structure can not only bear heavier display screen,and can also improve the ability of resist the external force under abnormal use.Considering above two technical indicators,two tests are designed in enterprise before production.First,thrust destroy is set to check hinge strength,it must make sure that deformation and fracture can't happen with the force of 5 times of the maximum torque;Second,swing life test is set to simulate users' opening/closing action to inspect hinge working cycles,it requires that after 60000 times opening/closing movements,hinge torque can't decay by more than 15%,and elastic deformation or fracture can't happen.The main research in this paper includes the following four aspects:1)To introduce Notebook PC hinge and it's structures briefly,including the common hinge structure,torque generation principle,etc.,additionally to introduce the related tests in hinge development process and clarify the tests standard.2)Through the NX Nastran advanced simulation function,the original design is analyzed by static analysis,and the maximum stress value and maximum stress position are obtained.According to the test standard of enterprises,do damage experiment for each hinge single part,the experimental results agree with the simulation results,that proves the application of finite element simulation analysis can instead the actual experimental well,and at the same time the problem of insufficient strength of initial design is put forward.3)On the basis of statics analysis,combined with the fatigue cumulative damage theory and fatigue life analysis was carried out on the initial design,the analysis results are consistent with swing test life and failure position,fatigue life analysis proves that the use of finite element for the rotation can be feasible.4)Three improvement directions are proposed based on the weak spots obtained from the previous analysis:(a)Comparison of different materials;(b)Comparison of different sizes;(c)Comparison of different structures,according to the analysis results to work out the best improvement scheme and makes improvement model,respectively,to do destroy test and hinge cycle test,test results meet the test standard and life has been prolonged from the original 30000 ~ 35000 times to 80000 times above(according to switch 15 times a day on average,the service life increase from about 6 years to over 14 years),satisfied the test standard of the enterprise,and solved the practical engineering problems.The significance of this study is to apply CAE technology to analyze the different schemes of hinge and to get the best solution,reduce the times of verification test and improve the design efficiency.