The buckling torque may be much less than the yield torque in very thin rectangular tubes under torsion. In this paper, simple closed-form formulae are presented for buckling analysis of long hollow rectangular tubes under torsion. By the presented formulae, one can obtain the critical torque or the critical angle of twist of the tube in terms of its geometrical parameters and material constant...

The Rotary-Draw Bending (RDB) process is a distinguished process employed for the precision cold bending of a hollow tube with small radius bends using Numerical Control (NC) machines. This research presents an analytical model based on the power law hardening model for the RDB processing of rectangular thin tubes. Based on the constraints of the tube in the dies and its thinness, the plane str...

the welding in cold formed areas is not only an open question for statically loaded sections (brittle fracture) but also for dynamically loaded structures (fatigue resistance). a lot of structures are subjected to dynamic loadings and unfortunately very little information about the influence of welding in the cold formed areas on fatigue resistance is available. in order to establish the fatigu...

This paper describes the computations of micro-strains at inner corner of cold formed rectangular hollow sections (CFRHS) made up of structural steels using finite element analysis. In order to obtain the micro-strains, distortion test is simulated by modeling two-dimensional structural steel tubes in ANSYS software. Two dimensional linear static analyses are performed by defining elastic prope...

Hollow sections have been widely used for steel structures. Applications of High Strength Steel (HSS) on cold-formed hollow sections lead to thinner and lighter structures. This paper presents numerical investigations on the lateral-torsional buckling resistance of the cold-formed high strength steel rectangular hollow beam. Results from finite element analysis using Abaqus software are compare...

In order to realize a single-layer corporate-fed slot array, a hollow rectangular coaxial line is adopted as a feeding line. A 2×2-element subarray on a hollow rectangular coaxial line for the corporate-fed array is designed for the 60-GHz band. For the wideband operation, a cavity-backed wide slot is adopted as a radiating element. The 5.7% bandwidth for the reflection less than −20 dB is obta...

Studies of multipactor resonances in coaxial and hollow waveguide via standard particle trajectory and secondary emission numerical simulation techniques are presented. Agreement between simulations and experimentally observed multipactor barriers gives confidence in results of simulation studies of a wedgeshaped hollow waveguide geometry that shows promise of being far less susceptible to mult...

Hollow silica tubes with mesoporous wall structure were synthesized through the sol-gel reactions of tetraethoxysilane and n-octadecyltrimethoxysilane (TEOS/C18-TMS) on the surface of ammonium dl-tartrate crystals. Novel hollow carbon tubes with mesoporous walls and rectangular-shaped channels were fabricated using the silica tubes as templates.