There was a need to analyze the behavior of the rubber diaphragm inside a pneumatic valve. The hyperelastic material constants [1] of the diaphragm material were determined by the testing of the material. Numerical model of the diaphragm was created and analyzed in the FEM (fine element method) system [2]. Based on the obtained results the optimized shape of the diaphragm was designed and its behavior was simulated. The new more suitable shape of the diaphragm is the result of this work
