جستجوی مقالات مرتبط با کلیدواژه « جذب انرژی » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

High energy absorption capacity of rubber foam, during the large compression deformations of cell structure, is an important variable that is considered by engineers as a design criterion. In this respect, the energy absorption behavior of acrylonitrile butadiene rubber (NBR) foam with different densities was studied by efficiency and acutest parameters.

The closed cell NBR foams with densities of 0.51, 0.63, 0.72 and 0.79 g/cm3 were prepared by changing the amount of compound in the equal volume of the mold. The cell morphology and compressive properties of the foams were analyzed by scanning electron microscopy (SEM) and compression tests, respectively.

The cell morphology analysis has indicated that by decreasing the foam density, the average cell diameter becomes larger, the number of cells per unit volume decreases and the cell size distribution becomes heterogeneous. In the compression test, by decreasing density from 0.79 to 0.51 g/cm3, the plateau stress decreases from 750 to 246 kPa and the corresponding stress with the maximum efficiency decreases from 1.13 to 0.27 MPa. In the low stress range, 0.3 MPa, by decreasing density from 0.79 to 0.51 g/cm3, the energy absorption of foam changes from 0.39 to 0.009 MJ/m3. As a result, in the low stress range, lower density foams show more energy absorption. While in the high stress range, higher density foams absorb more energy. For example, in the 1.3 MPa stress, the energy absorption of foams with the density 0.51 g/cm3 and 0.79 g/cm3 is about 0.88 MJ/m3 and 0.1 MJ/m3, respectively. Therefore, the energy absorption capacity of the foam depends on the density and stress range, which determines the maximum allowable stress of the foam based on its density.

For many engineering applications، the ability to absorb energy is of highest priority in selection of materials and designing structures، especially structures that go under the impact forces during their application. Body of the vehicles should display high performance to protect passengers against impacts and collisions. This matter، has found double importance with increasing speed and number of vehicles. Auxiliary equipments، such as protective safety helmet، also need to have high energy absorption capacity. Honey combs، sponges، and corals are examples found in nature. Cellular textile composites due to several advantages such as low weight، high strength and energy absorption are frequently used. In this paper، energy absorption capability of PVC-foam reinforced by 3D weft-knitted fabrics has been examined. The energy absorption of 3D weft-knitted fabric composites was investigated based on their tensile and compression properties. From the test results it was found that the foam filled composite egg-box panels showed good energy absorption capacity with smooth stress–strain curves which resembles the ideal energy absorber.