جستجوی مقالات مرتبط با کلیدواژه "شیبه سازی عددی" در نشریات گروه "مواد و متالورژی"

The most important objective in the drop weight tear test (DWTT) is obtaining the fracture energy. DWTT use in the military, steel and pipeline industries. By installing the proper equipment, the dynamic impact load can be measured in terms of the hammer displacement of the DWTT machine and it can calculate many parameters such as initiation energy, propagation and total fracture energy. For this purpose, numerical analysis by ABAQUS software was used to determine the proper location of the strain gauge on the hammer. Then, the strain gauge circuit (load-cell) was installed and calibrated using analytical and experimental methods. In order to use the circuit, the voltage must be converted to the load values. The analytical and experimental methods were used to obtain the desired coefficient. The two coefficient had an acceptable difference. In addition, in order to increase the accuracy and repeatability, other equipment such as guide and micro-swich were used in the DWTT machine. Experiments with the DWTT machine showed the repeatability of the results.

In this paper, the inclined impact of a droplet on a solid surface in a spray coating process is studied using both numerical and analytical models. The numerical simulation is based on a previously developed model that includes the solution of Navier-Stokes equations along with an equation for the liquid free surface. The contact angle is modeled using two advancing and receding angles at the liquid front on the solid surface. The close agreement between the results of the numerical model with those of the experiments shows that the model can accurately predict the droplet impact behavior. Using the balance of droplet energy before and after the impact, a simple analytical model is presented for the maximum spread of a droplet during an inclined impact. This model is an extension of a previously developed model for the normal impact of a droplet on a solid surface. A comparison between the results of the analytical model with those of the simulations and experiments verifies the accuracy of the analytical model predictions for the maximum spread of a droplet in a spray coating process. Based on the analytical model, for high Reynolds numbers and small angles of impact, the effect of Weber number on the maximum spread is increased. For low Reynolds numbers and impact angles close to 90o, the maximum spread remains nearly constant