The effect of cyclic twist angle on mechanical properties for AISI 1038 medium carbon steel

A group of 11 specimens AISI 1038 Medium carbon steel alloy fabricated according to ASTM standard D790-02 torsion test were twisted cyclically one in positive another to negative angle in range of angles (0o-50o), step 5 degrees for each specimen. The data from torsion test device help to get actual torques and shear stresses, later the specimens tested the tensile test to figure out the effects of cyclic angle of twist on mechanical properties for AISI 1038 Medium carbon steel. The results showed a good agreement between the theoretical and actual data (torque, shear stress) for specimens with positive angle of twist by the percentage: 98%, 91%, 96%, 93%, 91%, 89%, 88%, 85%, 82%, 81%, 80%. In other side the results for experimental tests showed a dangerous decrements in mechanical properties for cyclic or negative twist angles, the yield stress for reference specimen without twist angle is 490 Mpa, yield stress increased for angels (5o,10o,15o) by 1%, 3%, 6%, then decreased for angels (20o,25o,30o,35o,40o,45o) by 3%, 5%, 13%, 18%, 24% and 35% Respectively and the final specimen with 50o angle of twist had been broken torsional before tensile test as a result specimens groups consequent of the extrusion – intrusion defects concomitant from twisting load

Experimental and simulation study of mild steel response to lateral quasi-static compression

Collision of structure of a vehicle is not limited to the axial direction but it can occur laterally. The purpose of this paper is to present a study of the energy absorption behavior of different length of the circular mild steel tube under lateral crushing. A ring/tube (length of 10 mm, 35 mm, and 60 mm), 60 mm diameter and 1.5 mm thickness is compressed quasi-statically. Maximum loading setup to Instron machine was 50 kN. The speed of compression is 5mm/min. Finite Element Analysis (FEA) it used to validate the experimental work to ensure of getting accurate results. Numerical results of energy absorption and collapse load showed respectively 96.52% and 94.36% agreement with experimental results. The theoretical results showed 14.37% deviation with experimental and 15.5% with numerical results. The specimen with 60 mm length leads to better energy absorption than the other specimens. The results obtained numerically and experimentally in addition to theoretically showed the energy absorbed and collapse load varies with the length of the tube