Research on Three-point Bending Mechanical Performance of Square Tube Structure Filled with Foam Aluminum

In this paper, the quasi-static three-point bending experiments are carried out to study the deformation behavior of square tube and square tube filled with foam aluminum. The difference of bending deformation mode, loading characteristics and energy absorption efficiency between tube and foam aluminum filled tube is compared. And the influence of adhesive between the foam aluminum core and the tube wall on the bending deformation of square tube filled with foam aluminum is analyzed. Based on the bending super beam element model of tube structure, the relationship between the moment and rotation of square tube filled with foam aluminum under transverse static loading is analyzed. And the formula for calculating the moment and rotation angle of square tube filled with foam aluminum at three-point bending is obtained. In order to compare the simulation results, theoretical calculation results and experimental results of quasi-static bending, the three-point bending deformation of square tube and filled with foam aluminum under quasi-static and impact loading is simulated by finite element method. The results show that the filling of foam aluminum can improve the bearing capacity and energy absorption performance of the square tube structure. Under the bending load, the deformation degree of the bearing section is greatly reduced, which increases the bearing capacity of the structure and increases the stability of its bending resistance.

X-ray Radiography Inspection of Pores of Thin Aluminum Foam during Press Forming Immediately after Foaming

Forming aluminum foam to the desired shape while retaining its pore structures is essential for manufacturing aluminum foam products. Recently, a press forming process for aluminum foam that is performed after precursor foaming but before solidification has been proposed. In this study, to track individual pores throughout press forming immediately after foaming, X-ray radiography inspection was applied. A thin precursor was used, and foaming was constrained to the X-ray transmission direction. It was shown that, although some pores coalesced with other pores, the pores did not collapse during press forming. In addition, the porosity of aluminum foam evaluated from X-ray transmission images was constant during press forming. Some pores retained their shape during press forming but their position was changed by the material flow generated by press forming. These results show that by press forming before the solidification of aluminum foam, aluminum foam can be shaped without the collapse of pores.

APPLICATION OF COPPERED POLYSTYRENE SPHERES IN CASTING PRODUCTS

A technological scheme for obtaining an experimental foam aluminum material with a fixed arrangement of closed pores inside the casting is presented. As a blowing agent, polystyrene foam granules were used on the surface of which a copper galvanic coating was applied in several ways.

Analysis of the Loading on an Articulated Flat Wagon of Circular Pipes Loaded with Tank Containers

This research is concerned with the use of double walls filled with foam aluminum for an open wagon to decrease loading during operational modes. The research presents the strength calculation for the frame of a wagon with a consideration of the engineering solutions proposed. It was found that the maximum equivalent stresses appeared in the bottom section of the center sill behind the back support; they amounted to about 290 МPа and did not exceed the allowable values. The maximum displacements were in the middle parts of the main longitudinal beams of a section, and they amounted to 8.8 mm. The research also presents the strength calculation for a weld joint in the maximum loaded zones of the frame of a wagon and reports the results of the modal analysis of the frame of the improved wagon. It was found that the oscillation frequencies did not exceed the allowable values. The results of the research may be useful for those who are concerned about designing innovative rolling stock units and improving the operational efficiency of railway transport.

PROSPECTS FOR THE USE OF HOT ISOSTATIC PRESSING IN CAST ALUMINUM ALLOYS (review)

Provides an overview of methods for producing porous aluminum, its properties, advantages and disadvantages, and considers the use of aluminum foamed materials in the aerospace and mechanical engineering industries. It has been established that the mechanical properties of foam aluminum depend on the size and location of the pores, as well as on the method of its production; carrying out the process of modeling the deformation of samples with different pore diameters and the type of porous structure will make it possible to control the mechanical properties of a porous aluminum alloy.

Topological optimization of the roofing structure of a passenger vehicle to increase energy intensity in a side impact

This article considered the main issues of finding options for strengthening the roofing of the ve-hicle body based on topological optimization in order to meet the requirements of passive safety with a minimum mass. The method for achieving this goal was mathematical modeling using the Topology Optimization modules of the ANSYS software package and the explicit dynamics of LS-Dyna. In order to test the effectiveness of the reinforcements, the pillar side impact according to UNECE 135 “Uniform provisions concerning the approval of vehicles with regard to their perfor-mance in side impact on a pillar” was selected as the loading mode. The efficiency criterion was the energy intensity of the body, defined as the ratio of the energy of the system to the residual (plastic) deformation at the level of the center of the door. Based on the topological optimization, two vari-ants of the arrangement of the reinforcing elements, practically equivalent in efficiency, were ob-tained. For the most complete assessment of the influence of the parameters, several options for strengthening the roofing were considered: placement of steel reinforcing elements; placement of foam aluminum under the roof; combination of steel elements with filling their cavities with foam aluminum. Based on the simulation results, a comparative assessment of the effectiveness of the considered amplification options was carried out. The most effective were the options for reinforc-ing the roofing with channel-shaped beams and filling them with foam and the option for reinforc-ing the roofing with channel-shaped beams and diagonal bridges in them, causing it to increase compared to the original structure by 20.88 and 19.94%, respectively, but at the same time the mass of the first option is 42 kg less than the mass of the second.