Purpose: In the study, evaluation of the relation between physical and mechanical properties and NVH performance of viscoelastic expandible adhesive materials is aimed. Viscoelastic, high temperature expandible polymer materials are used as passive method to improve perceive quality and NVH performance of the vehicle by increasing NVH performance as damping vibration. In the first aspect, the customer listens and observes the noise by closing mobile parts of vehicle as doors. These viscoelastic damping materials are generally applied between metal components in doors, they are cured and expanded at high temperature in paint shops. After curing there are micropores inside the material like sponge and in application side, they have duties as adhesive bonding and viscoelastic damping. Method: The method of this study investigation of mechanical performance of NBR based thermal expandible viscoelastic adhesive effects on NVH performance (damping factor %) in four modes by measuring lap shear separation forces, hardness (shore A), tensile strength and elastic modulus and by calculating damping factor with respect to impact hammer excitation at 22 ± 2 ⁰ C, 50% RH. Findings: According to results, when mechanical properties as lap shear force and hardness shore A increase, elastic modulus, and tensile strength decrease; 1st, 2nd, and 4th modes are affected positively but 3rd mode is affected negatively. In addition, when lap shear force and elastic modulus are increasing, shore A and tensile strength are constant; damping factors % are increasing. Although when lap shear force is increasing; shore A, elastic modulus and tensile strength are close each other; damping factors % in four modes are more precise. Conclusion: Hardness Shore A, tensile strength, lap shear strength and elastic modulus influence damping factors for four modes. It had been estimated if lap shear force and cohesive forces increase, damping factors would decrease because of damping of vibration through porous material and their walls. It was observed that the estimation is not completely true for all cases. Damping factors and the mechanical properties for these viscoelastic, paste curable adhesive materials also depend on formulation of the polymer. In addition, test temperature and humidity effect damping factor (NVH performance). ORCID NO: 0000-0002-0731-6425
Anahtar Kelimeler: Door Closure Noise, Rubber, Shore A, Viscoelastic, Vibration
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