Dirk Mohr, PhD

 École Polytechnique
LMS, Room 03.10.06
Palaiseau, France

phone +33.1.6933.5801
email  mohr@lms.polytechnique.fr

Current Position

Chargé de Recherche au CNRS
CNRS Research Assistant Professor
at the Laboratoire de Mécanique des Solides (LMS)
CNRS UMR 4976, Department of Mechanics
Ecole Polytechnique, France

Research Affiliate
MIT, Department of Mechanical Engineering
Cambridge, MA, USA

Education

 Dipl.-Ing., 1999, University of Karlsruhe
M.S., 2000, MIT
Ph.D., 2003, MIT



Localization of deformation in the cellular micro- structure of aluminum honeycomb under multiaxial loading. The photograph shows the deformed honeycomb cell walls at the end of the buckling dominated non-linear elastic regime prior to plastic collapse. Mohr D, Doyoyo M, J. Appl. Mech. , 2004.



Considerable weight savings may be expected when newly developed sandwich sheets are used as base material for crash relevant automotive components. Understanding the plasticity of sandwich core materials such as metallic honycombs at various scales is crucial for the successful design of  future engineering structures. 

Journal Publications

Grolleau, V., Gary, G., and Mohr, D. (2007).
Biaxial Testing of Sheet Materials at High Strain Rates Using Viscoelastic Bars, Experimental Mechanics, in press.

Mohr, D. and Oswald(6), M. (2007).
A New Experimental Technique for the Multi-axial Testing of Advanced High Strength Steel, Experimental Mechanics, in press. >download

Mohr, D. and Gary (5), G. (2007).
M-shaped Specimen for the High-Strain Rate Testing Using a Split Hopkinson Pressure Bar Apparatus, Experimental Mechanics, in press. >download

Mohr, D. and Henn(3), S. (2007).
Calibration of Stress-triaxiality Dependent Crack Formation Criteria: A New Hybrid Experimental-Numerical Method, Experimental Mechanics, in press.   >download

Mohr, D. and Treitler (3), R. (2007).
Onset of Fracture in High Pressure Die Casting Aluminum Alloys, Engineering Fracture Mechanics, in press. >download

Mohr, D., Xue(2), Z. and Vaziri(2), A. (2006).
Quasi-static Punch Indentation of a Honeycomb Sandwich Plate: Experiments and Modeling, Journal of Mechanics of Materials and Structures 1(3), 581-604. >download

Mohr, D. (2006).
Multi-scale Finite-strain Plasticity Model for Stable Metallic Honeycombs Incorporating Microstructural Evolution, International Journal of Plasticity, 22(10), 1899-1923. >download

Mohr, D. and Wierzbicki, T. (2006).
On the Crashworthiness of Shear-rigid Sandwich Structures, Journal of Applied Mechanics 73(4), 633-641. >download

Doyoyo(1), M. and Mohr, D. (2005).
Experimental Determination of the Mechanical Effects of Mass Density Gradient in Metallic Foams, Mechanics of Materials 38(4), 325-339. >download

Mohr, D. and Straza(4) , G. (2005).
Development of Formable All-Metal Sandwich Sheets for Automotive Applications, Advanced Engineering Materials 7(4), 243-246. >download

Mohr, D. (2005).
Mechanism-based Multi-surface Plasticity Model for Ideal Truss Lattice Materials, International Journal of Solids and Structures 42(11), 3235-3260. >download

Mohr, D. (2005).
On the Role of Shear Strength in Sandwich Sheet Forming, International Journal of Solids and Structures  42(5-6), 1491-1512. >download

Mohr, D. and Doyoyo, M. (2004).
Large Plastic Deformation of Metallic Honeycomb: Orthotropic Rate-Independent Constitutive Model, International Journal of Solids and Structures   41(16-17), 4435-4456. >download

Mohr, D. and Doyoyo, M. (2004).
Deformation-Induced Folding Systems in Thin-Walled Monolithic Hexagonal Metallic Honeycomb, International Journal of Solids and Structures   41(11-12), 3353-3377. >download
 
 Mohr, D. and Doyoyo, M. (2004).
Experimental Investigation on the Plasticity of Hexagonal Aluminum Honeycomb under Multiaxial Loading, Journal of Applied Mechanics  71(3), 37 >download

Mohr, D. and Doyoyo, M. (2003).
Nucleation and Propagation of Plastic Collapse Bands in Aluminum Honeycomb, Journal of Applied Physics   94(4), 2262-2270. >download  

Mohr, D. and Doyoyo, M. (2003).
A New Method for the Biaxial Testing of Cellular Solids, Experimental Mechanics 43(2), 173-182. >download

Doyoyo, M. and Mohr, D. (2003).
Microstructural Response of Aluminium Honeycomb to Combined Normal and Shear Loading, Mechanics of Materials 35(9), 865-876. >download

Mohr, D. and Wierzbicki, T. (2003).
Shear Folding of Soft-core Sandwich Profiles: Experiments and Analysis, International Journal of Mechanical Sciences 45(2), 253-271. >download

Mohr, D. and Doyoyo, M. (2002).
Analysis of the Arcan Apparatus in the Clamped Configuration, Journal of Composite Materials 36(22), 2583-2594. >download
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Co-author affiliations (outside MIT):       
(1) Georgia Institute of Technology, Atlanta, USA
(2) Harvard University, Cambridge, USA
(5) Ecole Polytechnique, Palaiseau, France
(3) BMW R&D, Munich, Germany
(4) Aerovison International, San Diego, USA
(6) ETH Zurich, Switzerland

 Conference Proceedings

Mohr D. and Gary(5) G. (2006). High Strain Rate Testing Using a Split Hopkinson Pressure Bar Apparatus.
Journal de Physique IV, 134, 627-622 (Proceedings of the 8th International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading, Dijon, France, edited by J. Cirne, R. Dormeval et al.). >download

Mohr D. and Wierzbicki, T. (2004).Crashworthiness of Thin Ultra-light Stainless Steel Sandwich Sheets: From the Design of Core Materials to Structural Applications. Proceedings of the SAE 2004 World Congress , 2004-01-0885.

Mohr D., Doyoyo, M. (2003). Conceptual development of honeycomb plasticity: Qualitative analogy with crystal plasticity,
Dislocations, Plasticity and Metal Forming, edited by A. S. Khan, NEAT Press, Fulton, MD, 573-575.

Doyoyo, M. and Mohr, D. (2002). Failure of aluminum honeycombs in the T-W plane: phenomenological and micro-structural analysis, oral paper,
Proceedings of the 14th US National Congress of Theoretical and Applied Mechanics, edited by R.C. Batra, E.G. Henneke, Virginia Tech, Blacksburg, VA, 558.

Wierzbicki, T. and Mohr, D. (2000). Crush response of double-walled sandwich box columns,
Proceedings of the Fifth International Conference on Sandwich Constructions, e dited by D. Zenkert and H.R.Meyer-Piening , Zurich, Switzerland.

Technical Reports

D. Mohr. Modeling of Inelastic Properties of a Honeycomb Core,
ICL Report 32, May 2000.

D. Mohr and J. Meyer. Crushing of Double-Walled Sandwich Profiles with Honeycomb Core,
ICL Report 37, June 2000.

D. Mohr. Buckling and Folding of Aluminum Sandwich Strips with a Honeycomb Core,
ICL Report 39, November 2000.

D. Mohr and T. Wierzbicki. Preliminary Crash Experiments on Stainless Steel Sandwich Components,
ICL Report 47, November 2000.

D. Mohr and T. Wierzbicki. Shear Folding of Sandwich Box Columns under Axial Loading,
ICL Report 58, May 2001.

D. Mohr and M. Doyoyo. Shear Testing of Aluminum Honeycomb using the Modified Arcan Apparatus: Numerical Analysis and Evaluation of the Testing Method,
ICL Report 60, May 2001.

Y. Bao, D. Mohr, M. Doyoyo and T. Wierzbicki. A study on Constitutive Models for Aluminum Foams,
ICL Report 70, November 2001.

D. Mohr and T. Wierzbicki. Experimental and Theoretical Study of the Crushing of HSSA Double-Cell Profiles,
ICL Report 71, November 2001.

D. Mohr and M. Doyoyo. Analysis of the Arcan Apparatus in the Clamped Configuration,
ICL Report 71, November 2001.

D. Mohr. Development of New Ultralight Aluminum Sandwich Sheets for Automotive Applications,
ICL Report 73, November 2001.

D. Mohr and M. Doyoyo. Enhanced Arcan Apparatus for the Biaxial Testing of Cellular Solids,
ICL Report 79, April 2002.

M. Doyoyo and D. Mohr. The Out-of-Plane Yield Behavior of an Aluminum Alloy Honeycomb under a Biaxial State of Stress - Part I: Experimental Observations.
ICL Report 80, May 2002.

D. Mohr. Elastic Buckling of Fully Clamped Plate under Combined In-Plane Loading.
ICL Report 93, November 2002.

D. Mohr and M. Doyoyo. FE-Simulation of Aluminum Honeycomb Microstructure Subjected to Combined Shear and Normal Loading.
ICL Report 94, November 2002.