Information About

Jian Cao Professor Chair, ME Graduate Studies Dept. of Mechanical Engineering Northwestern University 2145 Sheridan Road, Rm. A217 Evanston, IL 60208-3111, USA TEL: 847-467-1032  FAX: 847-491-3915 jcao@northwestern.edu link to research site BS Materials Engineering, Shanghai Jiaotong University(1989) BS Automotive Control, Shanghai Jiaotong University(1989) MS Mechanical Engineering, Massachusetts Institute of Technology (1992) PhD Mechanical Engineering, Massachusetts Institute of Technology (1995)

Honors and Awards

• Fellow, American Society of Mechanical Engineers, 2007
• Young Investigator Award, American Society of Mechanical Engineers/Applied Mechanics, 2006
• Outstanding Young Manufacturing Engineer Award, Society of Manufacturing Engineers, 2002
• Outstanding Young Investigator Award, Japan-US Flexible Automation, 2002
• Young Chinese Leader, Dragon Foundation, Hong Kong, 2002
• Ralph R. Teetor Educational Award, International Society of Automotive Engineers, 1999
• CAREER Award, National Science Foundation 1997-2001
• ALCOA Foundation award 1997
• General Electric Chair Professor, Northwestern University, 1996-1997
• Associate Editor, ASME Journal of Manufacturing Science and Engineering, April 2003 – present.
• Associate Editor, ASME Journal of Applied Mechanics, October 2005 – present.
• Guest editor, ASME Journal of Engineering Materials and Technology, October, 2001.
• Member, International Editorial Advisory Board of Chinese Journal of Mechanical Engineering- English Edition, distributed by ASME, October 2001 – present.

Research: Modeling design and control of manufacturing processes; instability analysis; solid mechanics.

    Two of the objectives of manufacturing research conducted at my group are 1) to better understand the mechanics of deformation/failure in the forming process and therefore design a forming process that maximizes material usage, and 2) to better detect/understand process variations and therefore have a systematic approach to increase the robustness of a process.  These two objectives ultimately require a creation of

A microforming apparatus

an integrated system, which needs predictive modeling, sensors and process innovation. I have been practicing this overarching goal on sheet metal forming, composite sheet forming, and recently on microforming.

    Microforming, as a subset in micro-manufacturing which is defined as fabricating submicron to micro sizes three-dimensional features, has found applications in connecting pins, medical devices, optical lenses, etc. We designed a handheld microforming apparatus. The apparatus has allowed us to show the effect of material microstructure and specimen size on the geometry of deformed pins and on the frictional behavior in the process. 
  
    Sheet metal forming or stamping is one of the most widely used processes in the manufacture of automobiles (about 300 parts per vehicle) and is also employed in the production of aircraft, appliances, and many other products.  My past ten years work in this area contributes the knowledge in both computational modeling and experimental testing. We bridge applied mechanics, control and manufacturing together for solving the complex forming challenges.

Deformed pins showing size effect

    Composite sheet forming has great potential as a valuable alternative to facilitating mass production of structural composites in automotive components. Structural composites contain continuous or long fiber reinforcements, which yield outstanding mechanical and physical properties including high specific strength and low specific weight. Stamping could reduce the cycle time by at least four times in comparison to liquid molding, which is currently the most common method of forming complex structural composite products in medium volumes. Research in this area is relatively new, with many of the preliminary results leading to more questions than answers as we move from concept to realization. Our work focuses on material characterization and we have co-organized an international benchmark test for examining the capabilities of various models and testing methods.

In the classroom

Professor Cao has taught the courses: Optimization in Manufacturing Processes, Advanced Metal Forming, Intro to CAD/CAM, Intro to Manufacturing Processes, and Intro to Mechanical Design and Manufacturing.

Selected publications

Cao, J. and Boyce, M., 1997, “A predictive tool for delaying wrinkling and tearing failure in cup forming”, ASME Journal of Engineering Materials and Technology, Vol. 119, October, pp.354-365.

Cao, J. and Boyce, M., 1997, “Wrinkling behavior of rectangular plates under lateral constraints”, International Journal of Solids and Structures. Vol. 34 (2), Section 5, pp.153-176. 

Cao, J., 1999, “Prediction of plastic wrinkling using energy method”, ASME Journal of Applied Mechanics, Vol.66, pp.646-652, September.

Cao, J., Kinsey, B. and Solla, S., 2000, “Consistent and minimal springback using a stepped binder force trajectory and neural network control”, ASME Journal of Engineering Materials and Technology, Vol.122, pp.113-118, January.

Kinsey, B. Liu, Z.H. and Cao, J., 2000, “A novel forming technology for tailor welded blanks”, Journal of Materials Processing Technology, Vol. 99, pp.145-153.

Lee, C.H. and Cao, J. (2001) "Shell formulation of multi-step inverse analysis for the design of axisymmetric deep drawing process", International Journal of Numerical Methods in Engineering, Vol.50, pp.681-706.

Yao, H. and Cao, J. (2002) "Prediction of forming limit curves using an anisotropic yield function with prestrain induced backstress", International Journal of Plasticity, Vol.18/8, pp.1013-1038. 

Peng, X.Q. and Cao, J (2002) "A dual homogenization and Finite Element approach for material characterization of textile composites ", Composites Part B, Vol. 33 (1), pp 45-56.

Cao, J., Wang, X., and Mills, F. A. (2002) "Characterization of sheet buckling phenomenon subjected to controlled boundary constraints", ASME Journal of Manufacturing Science and Engineering, August, 2002, Vol. 124, pp.493-501.

Cao, J., Xue, P., Peng, X.Q. and Krishnan, N (2003) “An approach in modeling the temperature effect in thermo-forming of woven composites”, Composite Structures, Vol. 61(4), pp.413-420.

Peng, X.Q., Cao, J., Chen, J., Xue, P., Luisser, D.S. and. Liu, L. (2004) “Experimental and numerical analysis on normalization of picture frame tests for composite materials”, Composites Science and Technology, Vol. 64, pp.11-21.

Liu, W. K., Han, W., Lu, H., Li, S., and Cao, J. (2004) “Reproducing Kernel Element Method, Part I Theoretical Formulation”, Computer Methods in Applied Mechanics and Engineering, Vol. 193, pp.933 - 951. 

Li, Shunping and Cao, J. (2004) “A hybrid approach for quantifying the winding process and material effects on sheet coil deformation”, ASME Journal of Materials Engineering and Technology, Vol. 126(3), pp.303-313, July.

Cao, J., Krishnan, N., Wang, Z., Lu, H., Liu, W.K., Swanson, A. (2004) “Microforming –Experimental investigation of the extrusion process for micropins and its numerical simulation using RKEM”, ASME Journal of Manufacturing Science and Engineering, Vol. 126, pp. 642-652.

Peng, X.Q. and Cao, J. (2005) “A continuum mechanics based non-orthogonal constitutive model for woven composites”, Composites: Part A Applied Science and Manufacturing, Vol. 36(6), pp. 859-874.

Buranathiti, T., Cao, J., Chen, W., Xia, Z.C. (2006) “A Weighted Three-Point-Based Methodology for Variance Estimation”, Optimization Methods, Vol. 38(5), 557 - 576. 

Hang Shawn Cheng, Jian Cao and Cedric Z. Xia (2007) “An Accelerated Springback Compensation Method”, International Journal of Mechanical Sciences, Vol. 49, pp.267-279.

Krishnan, N., Cao, J. and Dohda K. (2007) “Study of the Size Effect on Friction Conditions in Micro-extrusion: Part 1 – Micro-Extrusion Experiments and Analysis”, accepted to ASME J. Manufacturing Science and Engineering.

Cao, J., Cheng, S.H., Wang, H.P., and Wang, C.T. (2007) “Buckling of Sheet Metals in Contact with Tool Surfaces”, Annuals of the CIRP, Vol.56/1.