Experimental analysis and finite element modelling of mechanical stoppers under impact loading

The aim of this thesis is to determine and understand the characteristic of impact loading and reaction of different materials colliding to each other. In engineering area, especially for moving mechanisms, such designs needs to be constrained by electrical and/or mechanical stoppers which is a complex phenomenon and, this phenomena can not to be understood easily. To design a valuable stopper, designer needs to know the impact parameters and the resistance of the stoppers to the energy acquired during the impact occurrence. To do so, a known geometry used for antenna motion and simple rotational motion mechanism is examined and modelled in ANSYS/Mechanical. In parallel, this motion is modelled by analytical solution previously studied and can be found on the literature. Many studies are examined and many different solutions found in the literature to compare the results obtained from the finite element model. At the end of this study, for the known geometry, real time impact tests are carried on to see what happens exactly. During the tests, SIEMENS data acquisition software and LMS data acquisition hardware are used. For different materials such as Aluminum 6061-T6, Stainless Steel AISI 304 and Titanium Alloy Ti4-6Al-V are used as stopper and Aluminum 6061-T6 moving mechanism end. In addition, for the motion, impact is carried out at different rotational velocities of 5, 10, 15, 20, 25 and 30 rpm. Each result is recorded individually. To take the impact data, a tee rosette strain gauge is used to obtain the strain data of the stopper in time domain. Data results are examined and it is seen that the results for different impact velocities are consistent. As the velocity increases, elastic deformation at the surface of the stopper increases, while, impact duration does not change abruptly. The impact occurrence fits to the finite element model developed in ANSYS with a certain acceptable amount of error. Thus, this gives us to use the analytical models to obtain the impact force between the two materials. Keywords: Impact, Impact Mechanics, Collision, Collision Modelling, FEM, FEA, Collision Duration, Collision Indentation, Collision Mechanics