Fatigue and Fracture Testing Laboratory

To advance the science of material durability through cutting-edge research in fatigue and fracture mechanics, while educating future engineers and fostering innovation in fields like aerospace, biomedical implants, and renewable energy.
To be a leader in fatigue and fracture research by developing innovative testing methods, leveraging advanced manufacturing technologies, and building impactful industry and academic collaborations.

Welcome to the Fatigue and Fracture Research Lab

Fatigue and fracture testing is the process of testing the structure’s ability to sustain cyclic load to determine durability and lifespan.
As a leading research hub in the State of Arkansas, we specialize in investigating the complex behavior of materials under varying stress conditions, contributing to the development of robust and durable structures for a myriad of applications.
Our team of experts combines cutting-edge experimentation with theoretical expertise to address challenges in industries ranging from aerospace and automotive to renewable energy, biomedical implants and beyond.

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• Metal Fatigue

• Fracture Mechanics

• Additive Manufacturing

• Multiaxial Fatigue

• Failure Analysis

• Materials Mechanical Behavior

• Fatigue of Polymers

• Biomedical Implant Design

• Mechanical Behavior of Bone

• Composite Materials

• Damage Mechanics

• Mechanical Design

• Experimental Mechanics

Lab Director: Mohammad Amjadi, Ph.D. Assistant Professor of Mechanical Engineering Arkansas Tech University 1811 North Boulder Ave. Corley 222 Russellville, AR 72801 Phone: 479-964-0583, Ext. 4204 Email: mamjadi@atu.edu Google Scholar LinkedIn
Brayden May: Brayden May is an undergraduate researcher, majoring in Mechanical Engineering. His research focuses on the fatigue behavior of 3D-printed thermoplastics, contributing to advancements in additive manufacturing techniques and material durability testing.

Former Students: Minh Tran (Currently Development Engineer at First Solar) Minh Tran is a Mechanical Engineering graduate student doing research on fatigue behavior of porous titanium and thermoplastic cellular structures. Minh's research aims to enhance the performance and durability of materials used in advanced engineering applications. In addition to his academic work, Minh gained valuable industry experience during a summer internship at AESC US headquarters in Smyrna, Tennessee. As an electric vehicle (EV) and energy storage systems (ESS) battery cell process engineer intern, Minh developed an automated packaging machine capable of processing 15 battery cells per minute, improving efficiency and safety.
Genya Ohama: A Bachelor's student majoring in Mechanical Engineering at Arkansas Tech University, conducted fatigue testing experiments on 17-4 Stainless Steel material produced by binder jetting.

MONOTONIC TESION TESTING
Basic mechanical properties of materials can be obtained using a simple monotonic tension test. Properties such as elastic modulus, yield strength, ultimate strength, fracture stress, ductility, and elongation at break.

FATIGUE TESTING
Fatigue Testing measures the ability of samples to withstand the application of repeated load cycles to determine their stress limit with the corresponding life.

FRACTURE TOUGHNESS TESTING
Fracture Toughness Testing provides information about a material’s resistance to crack extension under a steadily increasing load.

FATIGUIE CRACK GROWTH TESTING
Crack growth testing involves subjecting materials to cyclic loading conditions to analyze the propagation rate of cracks, providing critical data for assessing the fatigue resistance and durability of the material.

HARDNESS TEST
Perform indentation on the sample, creating permanent deformation, to evaluate the material’s strength, ductility, and wear resistance.

FRACTOGRAPHY
Evaluate the fracture surface of the sample to determine the cause and analyze the failure in the engineering structure.

FRACTURE TOUGHNESS TESTING
Also known as the stress-relaxation test. Supply a constant load at a constant temperature over a period of time to determine the strength and heat resistance of a sample’s material.

1. Servopulser Servo Dynamic Systems

EHF-E SERVOPULSER, 50KN, ± 50 mm from Shimadzu

Features include:

Up to ±50 kN axial force capacity
GRIP SET, SPLIT FLANGE, 50KN
Crack growth and fracture toughness grip set and sensor
Wide range of grips, fixtures, and accessories

2. ROTATING BENDING
3. OPTICAL MICROSCOPE
4. HARDNESS TESTER
5. INFRARED CAMERA

Auburn University
University of Arkansas for Medical Sciences, Biomechanics lab

Conferences:

Amjadi, M, Brayden May, Genya Ohama, and Minh Hoang Tran; “Fatigue Behavior of Additively Manufactured PA6-GF TPMS Structures using FDM”, the ASTM International Conference on Advanced Manufacturing, Atlanta, GA, 2024.
Molaei, R, Amjadi, M; “Fatigue Behavior of Additively Manufactured Titanium TPMS Structures using Selective Laser Melting”, the ASTM International Conference on Advanced Manufacturing, Atlanta, GA, 2024.
Amjadi, M; Molaei, R, “A Comparison between Additive Manufacturing and Injection Molding Techniques”, the ASTM International Conference on Advanced Manufacturing, Washington, DC, 2023.
Amjadi, M.; Fatemi, A.,” A Critical Plane Fatigue Damage Model for Multiaxial Fatigue Life Prediction of Injection MoldedShort Fiber Reinforced Thermoplastic Composites”. 13th International Conference on Multiaxial Fatigue and Fracture (ICMFF13), New Orleans, LA, USA, 2022.
Amjadi M, Fatemi A., “Multiaxial Fatigue Behavior of Thermoplastics; Experimental Study and Modeling”. New trends in fatigue and fracture - NT2F19, Tucson, Arizona, USA, 2019.
Amjadi, M.; Fatemi, "Fatigue Behavior of High-Density Polyethylene: Effects of Temperature, Mean Stress, and Manufacturing Method," 12th International Fatigue Congress (FATIGUE 2018), Poitiers Futuroscope-France, May 2018.

Journal Publications:

Amjadi, M.; Fatemi, A.,” A critical plane approach for multiaxial fatigue life prediction of short fiber reinforced thermoplastic composites”. Composites Part A: Applied Science and Manufacturing, 2024. 180: p. 108050.
Amjadi, M.; Fatemi, A.,” A Fatigue Damage Model for Life Prediction of Injection Molded Short Fiber Reinforced Thermoplastic Composites”. Polymers. 2021, 13, 2250.
Amjadi, M.; Fatemi, A.,”Tensile Behavior of High-Density Polyethylene Including the Effects of Processing Technique, Thickness, Temperature, and Strain Rate”. Polymers 2020, 12, 1857.
Amjadi, M.; Fatemi, A.,” Creep and fatigue behaviors of High-Density Polyethylene (HDPE): Effects of temperature, mean stress, frequency, and processing technique”. International Journal of Fatigue. 2020; 141: 105871. doi: 10.1016/j.ijfatigue.2020.105871.
Amjadi, M.; Fatemi, A. Creep behavior and modeling of high-density polyethylene (HDPE). Polymer Testing 2021, 94, 107031, doi: 10.1016/j.polymertesting.2020.107031.
Amjadi, M.; Fatemi, A.,” Multiaxial Fatigue Behavior of Thermoplastics Including Mean Stress and Notch Effects: Experiments and Modeling”. International Journal of Fatigue. 2020; 136: 105571. doi: 10.1016/j.ijfatigue.2020.105571.
Amjadi, M.; Fatemi, A.,” Multiaxial Fatigue Behavior of High-Density Polyethylene (HDPE) Including Notch Effect: Experiments and Modeling”. ICMFF12 - 12th International Conference on Multiaxial Fatigue and Fracture; MATEC Web of Conferences. 2019; 300: 05001. doi: 10.1051/matecconf/201930005001.
Amjadi M, Nikkhoo M, Khalaf K, et al., “An in silico parametric model of vertebrae trabecular bone based on density and microstructural parameters to assess risk of fracture in osteoporosis”. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine. 2014;228(12):1281-1295. doi:10.1177/0954411914563363.

American Society of Naval Engineers

www.efatigue.com

Mohammad Amjadi, Ph.D.

Assistant Professor of Mechanical Engineering
Arkansas Tech University
1811 North Boulder Ave.
Corley 222
Russellville, AR 72801
Phone: 479-964-0583, Ext. 4204
Email: mamjadi@atu.edu