Effect of Geometrical Factors on Torsion in Cold Roll Forming of the Lower Side Beam of a Car

Cold roll forming is a continuous metal forming process used to produce a large variety of profiles. A significant product of cold roll forming is asymmetric profiles, whose application is expanding in the construction of cars, houses, bridges, etc. Torsion is one of the common defects in the cold roll forming process of asymmetric section steel and sometimes seriously affects cold roll forming products. With the development of the economy and technology, many asymmetric cold roll-formed parts are being gradually applied to automobiles. Three-dimensional finite element analysis models of 12 stands with 700L sheet material were carried out using the professional COPRA RF and MSC MARC software, taking the lower beam of an automobile as the research object. Five geometric factors of the lower side beam were researched, and the influence rules of different geometric elements on the forming torsion were analyzed. We found that with the increase of web width, flange width, and vertical edge height and the decrease of the corner radius and strip thickness, the torsion defects of cold roll forming were improved to different degrees. The results also showed that the width of the flange has the most significant effect on torsion.

Numerical investigation of the dynamic responses of steel-concrete girder bridges subjected to moving vehicular loads

The steel-concrete composite girder bridge is a new type of bridge. The steel girder and concrete slab are connected together by connectors and bear the common force so that the tensile performance of steel and the compressive performance of concrete can be fully utilized. The advantages are obvious. However, research on the dynamic analysis of steel-concrete composite beam bridges is still relatively rare, and the dynamic effects on these bridges from vehicles are becoming increasingly significant. In this paper, a more complex steel-concrete composite simply supported beam bridge model and the entire vehicle model are established, and five steel-concrete connection levels of the bridge model are considered. Using the finite element model, the effects of five factors, namely, bridge natural frequency, vehicle natural frequency, vehicle speed, vehicle lateral position and bridge deck roughness, on the dynamic load allowance ( DLA) of the composite girder bridge are studied. The influence of vehicle speed and bridge surface roughness on the DLA has a strong regularity. The change in the DLA of the lateral position of the vehicle is highly symmetrical, and the DLA value at the side beam is larger than that of the center beam. Changes in bridge vibration frequency and vehicle vibration frequency can bring about significant changes in the DLA, and the closer the two frequencies are, the more significant the DLA increases, and the more likely it is to produce resonance.

Study on welded joints’ stress state grade of aluminum alloy EMU body

PurposeBased on the DVS1608-2011 and IIW-2008 and BS EN15085-3 standards, the stress state grade of welded joints of aluminum alloy EMU (Electric Multiple Units) body was studied.Design/methodology/approachFirst, the calculation methods of the stress state grade of aluminum alloy welded joints analyzed by DVS1608-2011 and IIW-2008 standards were studied, and the two methods were programmed by the APDL language of ANSYS. Then, the finite element model of aluminum alloy EMU body was established; the static strength calculation result of the body was compared with the test result, and the error is basically within 10%. Finally, under the acceleration fatigue load provided by BS EN12663 standard, the fatigue analysis was carried out on the welded joint of the vehicle body, and the stress state of the welded joint of the vehicle body was studied according to IIW-2008 and DVS1608 standards, respectively.FindingsThe results show that the assessment method based on IIW-2008 standard is more rigorous, and the maximum stress factor of the longitudinal weld between the side beam and the side wall is 0.811; the position occurs in the area where the longitudinal weld of the side beam and the side wall is close to the lower door angle.Originality/valueThe stress state is medium, and the rest of the weld stress states are low.

Beam-Reconfigurable Multi-Antenna System with Beam-Combining Technology for UAV-to-Everything Communications

This paper proposes a beam-reconfigurable antenna for unmanned aerial vehicles (UAVs) with wide beam coverage by applying beam-combining technology to multiple antennas with different beam patterns. The proposed multi-antenna system consists of a circular patch antenna and a low-profile printed meandered monopole antenna. For beam combining, a coplanar waveguide with ground (CPW-G) structure feeding network is proposed, and it consists of two input ports, a 90° hybrid coupler, a microstrip 90° phase delay line, and a single-pole double-throw (SPDT) switch. It performs the role of power distribution and phase adjustment, and synthesizes the broad-side beam of the monopole antenna and the end-fire beam of the patch antenna to form the directive broadside beams in four different directions. The proposed antenna system operates at 5–5.5 GHz which covers both UAV ground control frequencies (5.03–5.09 GHz) and UAV mission frequencies (5.091–5.150 GHz). The peak gain, total efficiency, and half-power beamwidth (HPBW) of the antenna system are approximately 5.8 dBi, 76%, 145° in the elevation plane, and 360° in the azimuth plane respectively. Its electrical size and weight are λ 0 × λ 0 × 0.21 λ 0 at 5.09 GHz and 19.2 g, respectively.

Pemilihan Pemasok Dengan Mempertimbangkan Produksi Bersih/Green Manufacturing Pada Industri Otomotif

This study aims to select the best suppliers based on Fuzzy-AHP and ELECTRE methods in multinational automotive companies in Indonesia. Fuzzy AHP method is used to determine the weight of criteria and sub-criteria in reducing uncertainty and unclear information. Meanwhile, the ELECTRE method is used to rank alternative suppliers. Both methods are used to reduce subjective decisions and improve the accuracy of selected suppliers. After applying Fuzzy AHP and ELECTRE methods, the supplier chosen for the steel fuel tank is S1, for side beam impact is S2, wheel disc is S2, Seat is S1, door trim is S2, lamp is S3, headlining is S3, insulator is S1 and hose is S3.Keywords: JIT, supplier performance, Fuzzy-AHP, ELECTRE

Application of virtual and augmented reality techniques for visualizing the results of FEM numerical analyses

An innovative approach for presenting the results of numerical FEM analysis is presented. Proposed visualization method uses virtual and augmented reality techniques for this purpose. The practical application of the new tool is presented on the example of strength analysis of the side beam of the curtainsider semi-trailer.