Kapı fitilinin lineer ve lineer olmayan modellemesi ve araç titreşimine etkisinin incelenmesi

The interior noise level has been an important design criterion lately in automotiveindustry. Most of the interior noise is generated by the vibrating parts of the vehicle body,mainly the doors. The vibration characteristics of the door panels are affected by theweatherstrip seals. The weatherstrip seals exhibit nonlinear behavior with changingfrequency, compression amplitude, temperature and previous load history. Therefore theweatherstrip seals should be modeled accurately in order to predict the dynamicperformance of the automobiles under various load conditions. For this purpose, we firstdeveloped hyperelastic models of the weatherstrip seal using different strain energyfunctions. In order to estimate the coefficients of the strain energy functions, we used theexperimental tension, compression and shear data provided by the manufacturer of theseal. The coefficients were calculated using curve fitting in ANSYS. After thecoefficients were calculated, the compression test was simulated in ANSYS usingdifferent hyperelastic material models to obtain Compression Load Deflection (CLD)behavior of the weatherstrip seal. Then, compression experiment was conducted using arobotic indenter equipped with force and position sensors. The measured CLD data wasthen compared with the finite element model (FEM) results and the most suitablehyperelastic model for weatherstrip seal was selected. After the selection of thehyperelastic material model, we obtained the viscoelastic properties of the weatherstripseal. Viscoelastic properties were obtained using an ?Inverse Finite Element Solution?technique which required the hyperelastic material properties as an initial guess. Stressrelaxation tests were performed using the robotic indenter to determine the viscoelasticproperties. The required constants were calculated using an optimization algorithm inANSYS utilizing the experimental relaxation data as the reference point.Independent from the previous studies, we built a Single Degree of System (SDOF) todetermine equivalent stiffness and damping coefficients for the weatherstrip seal. The set-up includes a mass and weatherstrip seal underneath to simulate a spring and a dash-potsystem. Experimental modal analysis of the system was performed and equivalentstiffness and damping for the weatherstrip seal were determined.Finally, we conducted experimental and numerical modal analysis of the vehicle doorwith and without the weatherstrip seal. Experimental modal analysis was performed withtwo different configurations to determine the effect of the seal and the boundaryconditions on the vibration characteristics of the vehicle. Numerical modal analysis wasperformed by constructing the finite element model of the system and simulating thesame conditions in the computer environment. Equivalent stiffness values calculatedfrom the SDOF system experiment were used in the FEM. The experimental and modelpredicted results were compared and the effect of the seal on the vehicle dynamics wasdetermined.