Husain Almuslim - Academia.edu (original) (raw)

Papers by Husain Almuslim

Mechanical damage in transportation pipelines is a threat to its structural integrity. There are ... more Mechanical damage in transportation pipelines is a threat to its structural integrity. There are many parameters that affect the severity of the mechanical damage which are related to the pipe geometry and material properties, the defect geometry and boundary conditions, the loading cycle, and the pipe state of stress. To understand those effects, the utilization of numerical finite element analysis (FEA) has been used extensively to supplement the expensive; and thus, limited full-scale tests. The actual pipe material exhibits a number of special features including nonlinear elasticity, anisotropy, and cyclic softening which need advanced material modeling techniques. However, the success of the numerical material model to actually simulate the pipe material behavior could not be studied in detail previously due to the insufficient experimental data especially in cyclic pressure loading. The objective of this paper is to investigate the effect of material modeling using FEA on the integrity assessment of dented pipe under static and cyclic loading by simulating pipe denting followed by subsequent pressure cycles. Several material models are tested and calibrated against the measurements of full-scale tests to find the effects of material modeling assumptions (e.g. isotropy, yield point, hardening rule). The results show that a combined material model simulating all special features of nonlinear elasticity, anisotropy, and cyclic softening gives a very close representation of experimental data in terms of strain values and fatigue cycles to failure. Therefore, detailed material properties are needed to conduct accurate integrity assessments of dented pipes especially under cyclic conditions.

Volume 1: Upstream Pipelines; Project Management; Design and Construction; Environment; Facilities Integrity Management; Operations and Maintenance; Pipeline Automation and Measurement, 2012

ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 2010

Mechanical damage in transportation pipelines is a threat to its structural integrity. Failure in... more Mechanical damage in transportation pipelines is a threat to its structural integrity. Failure in oil and gas pipelines is catastrophic as it leads to personal fatalities, injuries, property damage, loss of production and environmental pollution. Therefore, this issue is of extreme importance to Pipeline Operators, Government and Regulatory Agencies, and local Communities. As mechanical damage can occur during the course of pipeline life due to many reasons, appropriate tools and procedures for assessment of severity are necessary. There are many parameters that affect the severity of the mechanical damage related to the pipe geometry and material properties, the defect geometry and boundary conditions, and the pipe state of strain and stress. Moreover, multiple damaged areas may exist and interact like in the case of a hit by a multiple-tooth excavator. The main objective of this paper is to determine the distance and orientation where interaction of multiple dents is significant. The strain and stress fields are evaluated for static pressure loading and the stress range and fatigue life are evaluated for cyclic pressure loading. Accordingly, guidelines are developed for the integrity assessment of multiple dents in oil and gas pipelines. The input parameters of the problem including the pipe material, pipe geometry, dent dimensions, and distance and orientation between two dents have a great variability. Therefore, probabilistic design approach is applied to determine the sensitivity and correlation between the output and input parameters. The base case deterministic FEA model has been validated with full-instrumented full-scale tests conducted by Pipeline Research Council International as part of their active program to fully characterize mechanical damage.

Proceedings of the Biennial International Pipeline Conference, IPC, 2012

ABSTRACT The interaction of dent with the weld has always been considered a threat to the pipelin... more ABSTRACT The interaction of dent with the weld has always been considered a threat to the pipeline. Therefore, Codes and procedure impose more stringent rules than normally applied to plain dents. For example, ASME B31.8 considers dents deeper than 2% and interacting with welds to be injurious and requires an engineering assessment if they are to be left without repair. The objective of this paper is to present a new method of assessment that utilizes finite element analysis couples with probabilistic design analysis. In this paper, the impact of interaction of dent with longitudinal welds and girth welds will be under static and cyclic pressure conditions will be evaluated. The combined effects are included in a single FEA model and the welds will be simulated by imposing initial residual stresses along the weld line. The first part of the paper uses deterministic analysis to present strain and stress contours at the end of indentation stage as well as the stress range and fatigue cycles at the end of pressure cycle stage for a longitudinal weld case as well as girth weld case. The second part uses probabilistic design analysis with variable geometry, material and pressure in addition to the weld location and residual stress value to determine the sensitivity of the strain, stress, and stress range to the input. Two probabilistic design analyses are conducted: one for the interaction of dent with longitudinal welds, the other for the interaction of dent with girth welds.

Journal of Pressure Vessel Technology, 2013

Failure in piping due to acoustic-induced fatigue can be considered catastrophic as it could happ... more Failure in piping due to acoustic-induced fatigue can be considered catastrophic as it could happen only after a few minutes of operation. Acoustic-induced fatigue occurs mainly in gas piping systems with high velocity where high energy is dissipated through pressure reducing stations and pipe branch connections. It usually results in pipe through wall longitudinal cracks, pipe detachment from saddle supports, and complete shear off of branch connections. There are existing design criteria to avoid acoustic-induced fatigue based on comparison of generated power level to an acceptable power level. This criterion is normally used for the design of pressure relief and flare piping where high gas velocity exceeding 50% of the speed of sound (i.e., 0.5 Mach) is expected. However, acoustic-induced fatigue has been experienced in systems due to intermittent operations. Two case studies are presented in this paper. The first one is during a steam-out operation to clean a newly constructed s...

Journal of Pressure Vessel Technology, 2011

Mechanical damage in transportation pipelines is a threat to their structural integrity. Failure ... more Mechanical damage in transportation pipelines is a threat to their structural integrity. Failure in oil and gas pipelines is catastrophic as it leads to personal fatalities, injuries, property damage, loss of production, and environmental pollution. Therefore, this issue is of extreme importance to pipeline operators, government and regulatory agencies, and local communities. As mechanical damage can occur during the course of pipeline life due to many reasons, appropriate tools and procedures for assessment of severity is necessary. There are many parameters that affect the severity of the mechanical damage related to the pipe geometry and material properties, the defect geometry and boundary conditions, and the pipe state of strain and stress. The main objective of this paper is to investigate the effect of geometry, material, and pressure variability on strain and stress fields in dented pipelines under static and cyclic pressure loading using probabilistic analysis. Most of the ...

Journal of Energy Resources Technology, 2003

In a refinery distillation plant, there are many components of interest to be analyzed thermodyna... more In a refinery distillation plant, there are many components of interest to be analyzed thermodynamically, e.g., the crude oil heating furnace, the distillation column and a network of heat exchangers. Previous studies showed that the highest exergy losses occur when there is a heat transfer process especially in the crude oil heating furnace where high quality fuel is used to heat the crude oil, which is a low quality duty, beside the high temperature difference. Therefore, it is proposed in this work to perform distillation in two stages rather than one to reduce heat duty of the heating furnace and thus reducing irreversible losses. In this paper, energy and exergy analyses of a traditional one-stage crude oil distillation unit and a newly proposed two-stage crude oil distillation unit are conducted to study energy and exergy efficiencies of these units and determine the exergy losses. The results are compared for both one- and two-stage distillation units. In this regard, a comme...

International Journal of Energy Research, 2005

This work deals with a thermodynamic analysis of crude oil distillation systems to study energy a... more This work deals with a thermodynamic analysis of crude oil distillation systems to study energy and exergy efficiencies for system analysis, performance evaluation and optimization. In this regard, a new analysis methodology is proposed, and the SimSci/PRO II (2000) is employed as a simulation package for the required parametric studies, particularly to study the effects of the distillation column temperatures and pressures on the efficiencies. The simulations are carried for the operating conditions of the model. It is found that the total irreversibility losses are 608 MW for a flow rate of 507 kg s À1 [e.g. 56% by the Atmospheric Distillation Unit (ADU), 26% by the Vacuum Distillation Unit (VDU) and 18% by the heaters]. The highest irreversibility losses occur in the ADU as the main separation takes place there. Of the losses, 6.2% are due to chemical exergy losses associated with the separation process itself. The rest of the losses are due to the physical exergy losses mainly because of the temperature difference. The energy efficiencies are 0.497 for the ADU, 0.579 for the VDU and 0.519 for the overall system. The exergy efficiencies are 0.433 for the ADU, 0.501 for the VDU, 0.821 for Heater 1, 0.956 for Heater 2 and 0.233 for the overall system. The overall efficiency is not equal to the product of the components efficiencies.

International Journal of Energy Research, 2001

In this paper we deal with the effects of varying reference temperature on the exergy efficiencie... more In this paper we deal with the effects of varying reference temperature on the exergy efficiencies of one-and two-stage crude oil distillation units. Such units essentially consist of the crude oil heating furnace, the distillation column and a network of heat exchangers. Since the exergy efficiency is a key parameter to see how well the system is performing, we undertake a study on the influence of the reference temperature on such efficiencies. In this regard, a commercial software package, SimSci/PRO II program is used for the calculations. The results show that increasing reference temperature decreases the exergy efficiency in both one-and two-stage crude oil distillation systems and also increases the difference between the exergy efficiencies of both systems. Therefore, the exergy losses increase in the crude oil distillation systems.