HENRI P. GAVIN
Associate Professor, Department of Civil and Environmental Engineering

Contact Information
122 Hudson Hall
919-660-5201 phone
919-660-5219 fax
Henri.Gavin@Duke.edu

---

Education

	PhD	University of Michigan Civil Engineering, 1994
	MSE	University of Michigan Civil Engineering, 1988
	BSE	Princeton University Civil Engineering, 1986

---

Experience

	2002-present	Associate Professor Dept. of Civil and Environmental Engineering, Duke University
	2001-present	Director Center for Applied Control, Duke University
	1995-2002	Assistant Professor Dept. of Civil and Environmental Engineering, Duke University
	1994-1995	Research Fellow Dept. of Civil and Environmental Engineering University of Michigan
	1991-1994	Research Assistant Dept. of Civil and Environmental Engineering, University of Michigan
	1989-1991	Research Staff, Dept. of Civil Engineering and Operations Research, Princeton University

---

Selected Publications

1. Shiraishi, T., S. Morishita, and H.P. Gavin, "Estimation of Equivalent Permability in MR Fluid Considering Cluster Formation of Particles," submitted, 2002.
2. Gavin H.P., C. Alhan, and N. Oka, "Fault Tolerance of Semi-Active Seismic Isolation," to appear, Journal of Structural Engineering, 2003.
3. Gavin, H.P., "Annular Poiseuille ow of ER and MR materials," Journal of Rheology, vol. 45, no. 4, (July-August 2001) pp. 983-994.
4. Gavin, H.P., "Multi-duct electrorheological dampers," Journal of Intelligent Material Systems and Structures, vol 12, no. 5, (May 2001) pp 353-366.
5. Gavin, H.P., "The Effect of Particle Concentration Inhomogeneities on the Steady Flow of Electro- and Magneto-Rheological Materials," Journal of Non-Newtonian Fluid Mechanics, vol. 71, (1997) pp. 165182.
6. Aldemir, U. and H.P. Gavin, "Optimal Semi-active Control of Base Isolated Structures," submitted, 2001.
7. Nichols, J.M., L.N. Virgin, and H.P. Gavin, "Damping Estimates from Experimental Nonlinear Time-Series," Journal of Sound and Vibration, vol. 246, no. 5 (Oct. 2001) pp. 815-827.
8. Gavin, H.P., "Control of Seismically-Excited Vibration using Electrorheological Materials and Lya-punov Methods," IEEE Transactions On Control Systems Technology, vol. 9, no. 1, (2001) pp.27-36.
9. Gavin, H.P., "Design method for high-force electrorheological dampers," Smart Materials and Structures, vol. 7, no. 5 (1998) pp. 664-673.
10. Gavin, H.P., R.D. Hanson, and F.E. Filisko, "Electrorheological Dampers I: Analysis and Design," Journal of Applied Mechanics, vol. 63, no. 3, (1996) pp. 669-675.

 

---

Honors and Awards

	2002	Japan Society for the Promotion of Science, Fellowship
	1998	National Academy of Engineering, Frontiers in Engineering, Participant
	1997	Packard Foundation Grant, Finalist
	1996	NSF CAREER Award
	1996	Junior Faculty Enhancement Award, Oak Ridge Associated Universities
	1991	Bailey, Steele & Mildred Tuition Fellowship, The University of Michigan
	1986	Elected to associate membership of Sigma Xi, Princeton University

 

---

Short Research Interest Descriptor

Dr. Gavin is developing models and applications for materials whose rheological properties may be controlled with electrical or magnetic fields.

---

Research Interest

Dr. Gavin has interest in the modeling and application of materials whose rheological properties may be controlled with electrical or magnetic fields. The constitutive properties of these so-called "electro-rheological" (ER) or "magneto-rheological" (MR) materials may be controlled rapidly (millisecond response time) with low-power electronics, and material property changes are completely reversible upon removal of the field. These materials are typically synthesized by suspending electrically or magnetically polarizeable particles (with 5 to 20 micron diameters, typically) in a liquid dispersant, and stabilizing the suspension with a dispersant. Volume fractions of the particulates in the dispersant are roughly 20 to 40 percent. When fields are applied to this suspension, the multi-pole interactions between particulates results in a self-organized micro-structure, transforming the material from a liquid to a paste. Material properties which are most sensitive to the field are the yield stress and pre-yield elasticity. The required fields to produce these efects are intense (2 to 6 kV/mm in ER materials and 0.8 to 1.3 Tesla in MR materials). The yield stresses developed in ER materials are typically 3 to 5 kPa and are 60 to 100 kPa in MR materials. Under owing conditions Dynamic models for these materials include the effects of inertia and viscoelasticity and plasticity and can describe the behavior of these materials over broad frequency ranges. Reduced-order models of an algebraic nature are useful for feedback linearization in control applications.

Dr. Gavin is most interested in vibration control applications of these materials. Due to the dissipative qualities of these materials, vibration control systems utilizing these materials are unconditionally stable. In addition, because of the low power requirements (one Watt of electrical power can typically control hundreds of Watts of mechanical power) many applications may be battery-powered. These characteristics have been confirmed by optimizing, testing, and modeling both ER and MR devices.

Due to non-linear constraints enforcing the dissipative nature of the devices, devising control algorithms for them is challenging. Solutions to the Hamilton-Bellman-Jacoby equations have shown that ER- and MR-based vibration control systems can outperform passive systems over a broad frequency range.

Back to Faculty Index >