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Hadi Hafezi

Seeking for full-time job

Seeking full-time job. I have two backgrounds (i) Stress analysis / CAE Engineer- analysis relating fatigue, stress and durability in automotive and plants industries (ii) Manufacturing and Product Engineer (Jig & Fixtures, Test & Inspection).

experience

Graduate Assistant  
University of Arizona, August 2013 to May 2017, Tucson, Arizona United States
(Research and Development)
In my Ph.D. dissertation, a novel fast modeling technique called peri-ultrasound that can model both linear and nonlinear ultrasonic behavior of materials is developed and implemented. Nonlinear ultrasonic response can detect even very small material nonlinearity. Quantification of the material nonlinearity at the early stages of damage is important to avoid catastrophic failure and reduce repair costs. The developed model uses the nonlocal continuum-based peridynamic theory which was found to be a good simulation tool for handling crack propagation modeling, in particular when multiple cracks grow simultaneously. The developed peri-ultrasound modeling tool has been used to model the ultrasonic response at the interface of two materials in presence of an interface crack. Also, the stress wave propagation in a half-space (or half-plane for a 2-dimensional problem) with boundary loading is investigated using peri-ultrasound modeling. In another simulation, well-established two-dimensional Lamb's problem is investigated where the results are verified against available analytical solution. Also, the interaction between the surface wave and a surface breaking crack is studied.

education

University of Arizona, Tucson  
Doctor of Philosophy, Engineering Mechanics, Aug, 2013 to May, 2017


National University of Ireland, Galway  
Doctor of Philosophy, Mechanical Engineering, Aug, 2012 to Jul, 2013


Certifications

  • ASME Standards & Certification Assessment Based Course
    ASME 
    January 2017
  • Parallel Programming and Optimization for Intel Architecture
    Colfax International 
    April 2016

publications

Peri-ultrasound for modeling linear and nonlinear ultrasonic response     
Published by (Ultrasonics)
Authors: Mohammad Hadi Hafezi, Reza Alebrahim, Tribikram Kundu.  Published May 05, 2017

The objective of this paper is to introduce a novel fast modeling tool called peri-ultrasound for linear/nonlinear ultrasonic wave propagation modeling. This modeling approach is based on peridynamic theory. It does not require monitoring of the crack clapping phenomenon or artificially changing the stiffness of the element when two surfaces of the crack come in contact. Peri-ultrasound tool enables us to detect the material nonlinearity in very early stages of crack growth. Nonlinear ultrasonic behavior could be nicely modeled by the proposed peri-ultrasound tool. It is investigated how the material nonlinearity is affected by the presence of thin and thick cracks. From the normalized spectral plots the degree of material nonlinearity can be measured by extracting a feature called sideband peak count (SPC). Structures containing a thin crack show noticeable increase in their nonlinear behavior.

An assessment of a strain‐life approach for fatigue crack growth     
Published by (International Journal of Structural Integrity)
Authors: Mohammad Hadi Hafezi, N. Nik Abdullah, José F.O. Correia, Abílio M.P. De Jesus,.  Published September 04, 2012

Fatigue crack growth models based on elastic‐plastic stress‐strain histories at the crack tip region and strain‐life damage models have been proposed. The UniGrow model fits this particular class of fatigue crack propagation models. The residual stresses developed at the crack tip play a central role in these models, since they are applied to assess the actual crack driving force. This paper aims to assess the performance of the UniGrow model based on available experimental constant amplitude crack propagation data, derived for several metallic materials from representative Portuguese bridges. It also aims to discuss key issues in fatigue crack growth prediction, using the UniGrow model, in particular the residual stress computation and the suitability of fatigue damage rules.