Finite element procedures for the numerical simulation of fatigue crack propagation under mixed mode loading

Alshoaibi, Abdulnaser M. Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.3

This paper addresses the numerical simulation of fatigue crack growth in arbitrary 2D geometries under constant amplitude loading by the using a new finite element software. The purpose of this software is on the determination of 2D crack paths and surfaces as well as on the evaluation of components Lifetimes as a part of the damage tolerant assessment. Throughout the simulation of fatigue crack propagation an automatic adaptive mesh is carried out in the vicinity of the crack front nodes and in the elements which represent the higher stresses distribution. The fatigue crack direction and the corresponding stress-intensity factors are estimated at each small crack increment by employing the displacement extrapolation technique under facilitation of singular crack tip elements. The propagation is modeled by successive linear extensions, which are determined by the stress intensity factors under linear elastic fracture mechanics (LEFM) assumption. The stress intensity factors range history must be recorded along the small crack increments. Upon completion of the stress intensity factors range history recording, fatigue crack propagation life of the examined specimen is predicted. A consistent transfer algorithm and a crack relaxation method are proposed and implemented for this purpose. Verification of the predicted fatigue life is validated with relevant experimental data and numerical results obtained by other researchers. The comparisons show that the program is capable of demonstrating the fatigue life prediction results as well as the fatigue crack path satisfactorily.

Finite element procedures for the numerical simulation of fatigue crack propagation under mixed mode loading

Abdulnaser M. Alshoaibi 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.3

This paper addresses the numerical simulation of fatigue crack growth in arbitrary 2D geometries under constant amplitude loading by the using a new finite element software. The purpose of this software is on the determination of 2D crack paths and surfaces as well as on the evaluation of components Lifetimes as a part of the damage tolerant assessment. Throughout the simulation of fatigue crack propagation an automatic adaptive mesh is carried out in the vicinity of the crack front nodes and in the elements which represent the higher stresses distribution. The fatigue crack direction and the corresponding stress-intensity factors are estimated at each small crack increment by employing the displacement extrapolation technique under facilitation of singular crack tip elements. The propagation is modeled by successive linear extensions, which are determined by the stress intensity factors under linear elastic fracture mechanics (LEFM) assumption. The stress intensity factors range history must be recorded along the small crack increments. Upon completion of the stress intensity factors range history recording, fatigue crack propagation life of the examined specimen is predicted. A consistent transfer algorithm and a crack relaxation method are proposed and implemented for this purpose. Verification of the predicted fatigue life is validated with relevant experimental data and numerical results obtained by other researchers. The comparisons show that the program is capable of demonstrating the fatigue life prediction results as well as the fatigue crack path satisfactorily.

Screening marine algae metabolites as high-afnity inhibitors of SARS-CoV-2 main protease (3CLpro): an in silico analysis to identify novel drug candidates to combat COVID-19 pandemic

Muteeb Ghazala,Alshoaibi Adil,Aatif Mohammad,Rehman Md. Tabish,Qayyum M. Zuhaib 한국응용생명화학회 2020 Applied Biological Chemistry (Appl Biol Chem) Vol.63 No.6

The recent dissemination of SARS-CoV-2 from Wuhan city to all over the world has created a pandemic. COVID-19 has cost many human lives and created an enormous economic burden. Although many drugs/vaccines are in different stages of clinical trials, still none is clinically available. We have screened a marine seaweed database (1110 compounds) against 3CLpro of SARS-CoV-2 using computational approaches. High throughput virtual screening was performed on compounds, and 86 of them with docking score< −5.000 kcal mol−1 were subjected to standardprecision docking. Based on binding energies (<−6.000 kcal mol−1 ), 9 compounds were further shortlisted and subjected to extra-precision docking. Free energy calculation by Prime-MM/GBSA suggested RC002, GA004, and GA006 as the most potent inhibitors of 3CLpro. An analysis of ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) properties of RC002, GA004, and GA006 indicated that only RC002 (callophysin A, from red alga Callophycus oppositifolius) passed Lipinski’s, Veber’s, PAINS and Brenk’s flters and displayed drug-like and lead-like properties. Analysis of 3CLpro-callophysin A complex revealed the involvement of salt bridge, hydrogen bonds, and hydrophobic interactions. callophysin A interacted with the catalytic residues (His41 and Cys145) of 3CLpro; hence it may act as a mechanism-based competitive inhibitor. Docking energy and docking afnity of callophysin A towards 3CLpro was −8.776 kcal mol−1 and 2.73×106 M−1 , respectively. Molecular dynamics simulation confrmed the stability of the 3CLpro-callophysin A complex. The fndings of this study may serve as the basis for further validation by in vitro and in vivo studies.

Actual fatigue reliability of structural material: Vibration efficiency

Hussain, Muzamal,Khadimallah, Mohamed A.,Ayed, Hamdi,Alshoaibi, Adil,Loukil, Hassen,Alsoruji, Ghazi,Tounsi, Abdelouahed Techno-Press 2022 Advances in concrete construction Vol.13 No.4

This paper is concerned with the vibration analysis of middle layer cylindrical shell made of functionally graded material. The outer layers and inner layer are composed of functionally graded and isotropic material respectively. The Rayleigh Ritz method is applied to solve the presented shell dynamics equations. Two configurations are constructed with layers distributions. Fundamental natural frequencies of the three layered cylindrical shell is plotted against the circumferential wave number with different power law exponents. The frequency decreases with the increase of power law exponent. The fundamental natural frequencies first decreases and fall down to its minimum value, after frequencies increases with circumferential wave number. This is due to change in the magnitude of extensional and bending energies of the cylindrical shells. The computer software MATLAB has been employed for the computation of presented frequencies and tested the results obtained in order to assess the accuracy and validity of the cylindrical shell model for predicting the vibration frequencies of cylindrical shell.

Settlement of velocity dissemination with fluid parameters for the configuration of stretching cylinder

Mudassar Jalil,Waheed Iqbal,Muzamal Hussain,Mohamed A. Khadimallah,Adil Alshoaibi,Jamel Baili,Khaled Mohamed Khedher,Elimam Abdallah Ali,Abdelouahed Tounsi 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.3

This investigation in fluid mechanics surrounds around the variety of flow problems for different fluids along the stretching cylinder. Numerical procedure is carried out for the obtained resultant equations by Keller-Box technique. Numerical study of laminar, steady, viscous and incompressible two dimensional boundary layer flow of effects of suction and blowing on boundary layer slip flow of Casson fluid along permeable exponentially stretching cylinder has been carried out in the present draft. physical parameters i.e., Nusselt number and skin friction coefficient, suction parameter and the local Reynold number are investigated on velocity profile and elaborated through proper graphs and table.

Structural monitoring of layered FGM distribution ring support: Analysis with and without internal pressure

Ghamkhar, Madiha,Harbaoui, Imene,Hussain, Muzamal,Ayed, Hamdi,Khadimallah, Mohamed A.,Alshoaibi, Adil Techno-Press 2022 Advances in nano research Vol.12 No.3

In this work, the vibrational frequency of two layered FGM cylindrical shell with and without the effects of internal pressure under ring support are discussed in detailed. The functionally graded materials of a cylindrical shell are designed for specific purpose and studied under various boundary conditions. The Love shell dynamical equations theory is utilized to find the relationship between the curvature displacement and strain displacement. Natural frequency vibrations are analyzed by using volume polynomial for bi-layered FGM shell under ring support both for with and without internal pressures.

Structural detection of variation in Poisson's ratio: Monitoring system for zigzag double walled carbon nanotubes

Hussain, Muzamal,Asghar, Sehar,Ayed, Hamdi,Khadimallah, Mohamed A.,Alshoaibi, Adil,Tounsi, Abdelouahed Techno-Press 2022 Advances in nano research Vol.12 No.4

In this paper, natural frequency curves are presented for three specific end supports considering distinct values of nonlocal parameter. The vibrational behavior of zigzag double walled carbon nanotubes is investigated using wave propagation with nonlocal effect. Frequency spectra of zigzag (12, 0) double walled carbon nanotubes have been analyzed with proposed model. Effects of nonlocal parameters have been fully investigated on the natural frequency against against variation of Poisson's ratio. A slow increase in frequencies against variation of Poisson's ratio also indicates insensitivity of it for suggested nonlocal model. Moreover, decrease in frequencies with increase in nonlocal parameter authenticates the applicability of nonlocal Love shell model. Also the frequency curves for C-F are lower throughout the computation than that of C-C curves.

Design and behavior of two profiles for structural performance of composite structure: A fluid interaction

Faisal Al Thobiani,Muzamal Hussain,Mohamed Amine Khadimallah,Emad Ghandourah,Abdulsalam Alhawsawi,Adil Alshoaibi 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.2

Two-dimensional stagnation point slip flow of a Casson fluid impinging normally on a flat linearly shrinking surface is considered. The modeled PDEs are changed into nonlinear ODEs through appropriate nonlinear transformations.The flow is assumed to be steady and incompressible, with external magnetic field acting on it. Similarity transformation is utilized to investigate the behavior of many parameters for heat and velocity distributions using truncation approach.The influence of buoyancy parameter, slip parameter, shrinking parameter, Casson fluid parameter on the heat profile. The effect of the magnetic parameter on the streamwise velocity profile is also investigated.

Hierarchical structure parameters in three dimensional turbulence: She-Leveque model

Imtiaz Ahmad,Lamjed Hadj-Taieb,Muzamal Hussain,Mohamed A. Khadimallah,Muhammad Taj,Adil Alshoaibi 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.29 No.5

Hierarchical structure parameters, proposed in She-Leveque model, are investigated for velocity components obtained from different flow types over a large range of Reynolds numbers 255 < < 720. The values of intermittency parameter , with respect to a fixed velocity component, are observed nearly same for all four types of turbulence. The parameter , for streamwise velocity components is nearly the same but significantly different for vertical components in different flows. It is also observed that for both parameters, an obvious relation between the longitudinal and transverse components < (and < ) always holds. However, the difference between and is found very small in all types of turbulent flows, we studied here. It is evidenced that at low Reynolds numbers, the deviations from K41 scaling are mainly due to the most intense structures and slightly because of more heterogeneous hierarchy of fluctuation structures. However, at higher Reynolds numbers the deviations seem as a consequence of the most intense structures only. Over all, the study suggests that the hierarchy parameter may be consider as a universal constant.

A system of several fraction laws for the identification of rotating response of FG shell

Yahya, Ahmad,Hussain, Muzamal,Khadimallah, Mohamed A.,Khedher, Khaled Mohamed,Al-Basyouni, K.S.,Ghandourah, Emad,Banoqitah, Essam Mohammed,Alshoaibi, Adil Techno-Press 2022 Advances in concrete construction Vol.13 No.3

The problem is formulated by applying the Kirchhoff's conception for shell theory. The longitudinal modal displacement functions are assessed by characteristic beam ones meet clamped-clamped end conditions applied at the shell edges. The fundamental natural frequency of rotating functionally graded cylindrical shells of different parameter versus ratios of length-to-diameter and height-to-diameter for a wide range has been reported and investigated through the study with fractions laws. The frequency first increases and gain maximum value with the increase of circumferential wave mode. By increasing different value of height-to-radius ratio, the resulting backward and forward frequencies increase and frequencies decrease on increasing height-to-radius ratio. Moreover, on increasing the rotating speed, the backward frequencies increases and forward frequencies decreases. The trigonometric frequencies are lower than that of exponential and polynomial frequencies. Stability of a cylindrical shell depends highly on these aspects of material. More the shell material sustains a load due to physical situations, the more the shell is stable. Any predicted fatigue due to burden of vibrations is evaded by estimating their dynamical aspects.