Dr. David Unger

Professor Emeritus, Mechanical and Civil Engineering

Room 257, Koch Center for Engineering and Science
812-488-2899
du2@evansville.edu

Dr. Unger is the author of the textbook, Analytical Fracture Mechanics, which was originally published in hard cover by Academic Press (1995), and later reprinted in paperback form by Dover Publications in 2001 and again in 2011. He was awarded the Sadelle and Sydney Berger Award for scholarly activity by the University of Evansville in 2005, the Dean's Teaching Award in the School of Engineering and Computer Science in 2006, the Dean’s Research Award in 2022, and designated a UE Global Scholar in 2007. He was a professionally licensed engineer for twenty years, and has served on the UE faculty for 21 years. In retirement, Dr. Unger continues to do research and publish technical papers.

Education

• PhD Theoretical and Applied Mechanics, University of Illinois at Urbana-Champaign.
• MS Aeronautical and Astronautical Engineering, University of Illinois at Urbana-Champaign.
• BS Aerospace Engineering, St. Louis University.

Experience

• Visiting Associate Professor, Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University.
• Acting Program Director of Mechanical Engineering Technology, Franklin University
• Assistant Professor of Engineering Mechanics at The Ohio State University.
• Postdoctoral Researcher, Department of Chemical Engineering and Materials Science, University of Minnesota.

Specialty Areas

• Nonlinear and Environmentally Assisted Fracture Mechanics
• Solid Mechanics
• Materials

Recent Publications

• Unger, D.J. Material stability criteria for a plane stress asymptotic solution for steady mode I crack growth in an elastic/perfectly plastic solid. Z. Angew. Math. Phys. 74, 174 (2023).
• Unger, D.J. Plane stress asymptotic solution for steady crack growth in an elastic/perfectly plastic solid for mode I crack propagation. Z. Angew. Math. Phys. 74, 77 pp. 1-21 (2023).
• D.J. Unger, The Modified Generalized Tresca Yield Condition with Application to Mode I Perfectly Plastic Crack Problems, Zeitschrift für angewandte Mathematik und Physik (Journal of Applied Mathematics and Physics) Z. Angew. Math. Phys. 74:1 (2023), pp. 1-11.
• D.J. Unger, Generalized Tresca yield condition as a family of elliptic curves with application to mode I crack problems, Zeitschrift für angewandte Mathematik und Physik (Journal of Applied Mathematics and Physics) ZAMP 73:184, 1-17 (2022).
• D.J. Unger, Yield Criteria Representable by Elliptic Curves and Weierstrass Form, Procedia Structural Integrity, 35, 2-9, 2022.
• D.J. Unger, Antiplane point load solution for a linear slot with rounded ends, Journal of the Mechanical Behavior of Materials, 29, 124-132, 2020.
• D.J. Unger, Comparison of series and finite difference solutions to remote tensile loadings of a plate having a linear slot with rounded ends, Journal of Mechanics of Materials and Structures, 15, 361-378, 2020.
• D.J. Unger, “ Visualizing the crack driving force through fluid analogy”, Journal of the Mechanical Behavior of Materials, 28, 89-94 (2019).
• Unger, D.J., “Free Streamline Hydrodynamic Analogy for a Linear Elastic Antiplane Slot Problem with Perfectly Plastic Ligaments at its Ends,” Journal of Elasticity, 132, 261-270 (2018).
• Unger, D.J., “A Theoretical Resistance-Curve Based on Nonproportional Plastic Strain,” International Journal of Fracture, 210, 207-211 (2018).
• Unger, D.J., “Path Dependent J-integral Evaluations around an Elliptical Hole for Large Deformation Theory,” Journal of the Mechanical Behavior of Materials, 25, pp. 77-81 (2016).
• Unger, D.J., “Linear Elastic Solutions for Slotted Plates Revisited,” Proceedings of XXIV International Congress of Theoretical and Applied Mechanics, pp. 2042-2043, IUTAM, Montreal (2016).
• Unger, D.J., "Contact Transform for the Biharmonic Equation Applicable to Plane Stress Elastoplastic Elliptical Hole Problems," J. of Elasticity, 117, 117-139 (2014).
• Unger, D.J., “ The yield condition strongly influences the formation of Dugdale plastic strips ahead of crack tips under tensile plane stress loading conditions,” J. of the Mechanical Behavior of Materials, 21, 37-39 (2012). (Courtesy of DE Gruyter)
• Unger, D.J. “Linear Elastic Solutions for Slotted Plates,” Journal of Elasticity, 108, 67-83 (2012).
• Unger, D.J., “ Analytical Fracture Mechanics,” 2nd reprint of text, Dover Publications (2011)
• Unger, D.J., “Large Plastic Deformations Accompanying the Growth of an Elliptical Hole in a Thin Plate,” Journal of Elasticity, 99, 117-130 (2010).
• Unger, D.J., “ A Plane Stress Perfectly Plastic Mode I Crack Problem for a Yield Condition Based on the Second and Third Invariants of the Deviatoric Stress Tensor-Part II,” Journal of Mechanics of Materials and Structures, 4, 1651-1656 (2009).
• Unger, D.J., “ A Plane Stress Perfectly Plastic Mode I Crack Problem for a Yield Condition Based on the Second and Third Invariants of the Deviatoric Stress Tensor-Part I,” Journal of Mechanics of Materials and Structures, 3, 795-807 (2008).
• Unger, D.J., “Path Independent Integral for an Elliptical Hole in a Plate under Tension for Plane Stress Deformation Theory,” Journal of Elasticity, 92, 217-226 (2008).
• Unger, D.J., “A Complete Perfectly Plastic Solution for the Mode I Crack Problem under Plane Stress Loading Conditions,” ASME Journal of Applied Mechanics, 74, 586-589 (2007).
• Unger, D.J.,  "Numerical Plane Stress Elastic - Perfectly Plastic Crack  Analysis under Tresca Yield Condition with Comparison to Dugdale Plastic Strip Model," Mechanics Research Communications, 34, 325-330 (2007).
• Unger, D.J., "A Plane Stress Perfectly Plastic Mode I Crack Solution with Continuous Stress Field," ASME Journal of Applied Mechanics, 72, 62-67 (2005).
• Unger, D.J. "Continuous Stress Field with Compatible Velocity Field for Plane Stress Perfectly Plastic Mode I Crack, Proceedings of McMat2005, Joint ASME/ASCE/SES Conference on Mechanics and Materials, June 1-3, 2005, in Baton Rouge, LA (LSU).  Invited speaker to technical session commemorating the lifelong contributions of E.C. Aifantis to mechanics and materials research.  Six page summary on CD.
• Unger, D.J., "Perfectly Plastic Caustics for the Opening Mode of Fracture," Theoretical and Applied Fracture Mechanics, 44, 82-94 (2005).
• Unger, D.J., Invited Contributor:  Problems of Fracture Mechanics and Fatigue, Eds:  Gdoutos, E.E, Rodopoulos, and Yates, J.R., Kluwer Academic Publishers, Dordrecht, 385-401 (2003).
• Unger, D.J. and Aifantis, E.C., "A New Class of Solutions of the Reduced Wave Equation Applicable to Crack Problems Related to Gradient Elasticity," Special edition of journal devoted to Fracture and Damage Mechanics (guest ed. E.E. Gdoutos) of Facta Universitatis - Series Mechanics, Automatic Control and Robotics, 3, 599-612 (2003).
• Unger, D. J., "Similarity Solution of the Flamant Problem by Means of a One-Parameter Group Transformation," Journal of Elasticity, 66, 93-97 (2002).
• Unger, D.J., “ Analytical Fracture Mechanics,” reprint of text, Dover Publications (2001)