Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : ABAQUS

Experimental and Numerical Investigation into Residual Stress During Turning Operation for Stainless Steel AISI 316

Safa M. Lafta; Maan A. Tawfiq

Engineering and Technology Journal, 2020, Volume 38, Issue 12, Pages 1862-1870
DOI: 10.30684/etj.v38i12A.1607

RS (residual stresses) represent the main role in the performance of structures and machined parts. The main objective of this paper is to investigate the effect of feed rate with constant cutting speed and depth of cut on residual stresses in orthogonal cutting, using Tungsten carbide cutting tools when machining AISI 316 in turning operation. AISI 316 stainless steel was selected in experiments since it is used in many important industries such as chemical, petrochemical industries, power generation, electrical engineering, food and beverage industry. Four feed rates were selected (0.228, 0.16, 0.08 and 0.065) mm/rev when cutting speed is constant 71 mm/min and depth of cutting 2 mm. The experimental results of residual stresses were (-15.75, 12.84, 64.9, 37.74) MPa and the numerical results of residual stresses were (-15, 12, 59, and 37) MPa. The best value of residual stresses is (-15.75 and -15) MPa when it is in a compressive way. The results showed that the percentage error between numerical by using (ABAQUS/ CAE ver. 2017) and experimental work measured by X-ray diffraction is range (2-15) %

Experimental and Numerical Analysis of Piled Raft Foundation Embedded within Partially Saturated Soil

M.R. Mahmood; S.F.A. Al-Wakel; A.A. Hani

Engineering and Technology Journal, 2017, Volume 35, Issue 2A, Pages 97-105
DOI: 10.30684/etj.35.2A.1

This paper presents an experimental and numerical study to investigate the load carrying capacity of piled raft foundation embedded within partially saturated sandy soil. The effect of matric suction on the bearing capacity of the foundation system was investigated. The experimental work consists of two models of foundation, circular raft foundation and circular piled raft foundation. The circular raft foundation has dimensions of 10cm in diameter, and 2.5cm thickness, while the piled raft foundation has the same dimensions of the circular raft model but with a single pile of 2.0cm in diameter and 40.0cm in length fixed at the center of the raft. Both models are loaded and tested under both fully saturated condition and unsaturated conditions, which are achieved by, predetermined lowering of water table. The lowering of water table below the soil surface was achieved in to two different depths to get different values of matric suction and the relationship between matric suction and depth of ground water table was measured in suction profile set by using three Tensiometers (IRROMETER). The soil water characteristic curve (SWCC) estimated by applying fitting methods through the software (SoilVision). A validation process then was carried out for the case of circular piled raft foundation with lowering the water table 45cm bellow soil surface in the aid of a sufficient finite element computer program ABAQUS 6.12. An eight-node axisymmetric quadrilateral element CAX8RP and CAX8R were used to simulate the soil continuum and piled raft respectively. The interaction method used to simulate the intersect surfaces of the system (pile-raft-soil) is a surface-to-surface discretization method under the concept of master and slave theory. The behavior of piled raft material is simulated by using a linear elastic model while the behavior of soil is simulated by an elasto-plastic model by the use of the Mohr-Coulomb failure criterion. The results of the experimental work demonstrate that the matric suction has a significant role on the bearing capacity of all tested models. It shows that the ultimate bearing capacity of circular raft foundation under a partially saturated condition is increases by about (7.0-8.0) times than the ultimate bearing capacity of fully saturated condition when lowering the water table 45 cm below the soil surface. While the ultimate bearing of circular piled raft foundation under partially saturated condition increases by about (8.0-9.0) times than the ultimate bearing capacity of fully saturated condition when lowering the water table 45 cm below the soil surface. The results of the ultimate bearing capacity of piled raft foundation that obtained from the experimental model and from the numerical modelling for the same soil condition and same matric suction indicate that a successful validation is achieved for the simulation process.

Study of Stress Intensity Factor in Corrugated Plate Using Extended Finite Element Method (XFEM)

Rafil Mahmood Laftah

Engineering and Technology Journal, 2016, Volume 34, Issue 15, Pages 2982-2992

The presence of crack with different lengths and locations in structure of corrugated plate is studied. XFEM is along with enrichment function based on partition of unity is used for the calculation of stresses due to the presence of crack. Stress intensity factors (KI) and relations for shape factors (C) are calculated for the four most common crack orientations and loading conditions. Results showed that crack in the flange with load perpendicular to corrugation direction yields higher values of KI and C in addition to wider spread of stress concentration contours than the web. When loading becomes parallel to corrugation direction, the stress intensity factor and C factor become remarkably less due to the corrugation stiffness. Third mode KIII is appeared in the fourth case in addition to the presence of the first mode KI due to 45o inclination of the web and applied load direction