RAGNAR H. LEDESMA, Ph.D., P.E.

**** **********, ******** *******, ** 48314

Mobile: 586-***-****

e-mail: adlclm@r.postjobfree.com

Technical Areas of Expertise:

Vehicle dynamics, control systems engineering, structural dynamics, multibody dynamics, structural analysis, stress analysis, finite element analysis, noise and vibration, material fatigue/durability, computational fluid mechanics, aerodynamics, flight mechanics, aeroelasticity, Matlab/Simulink, CarSim/TruckSim, ADAMS, ANSYS, NASTRAN, Creo Simulate, Recurdyne, Particle Works CFD, SC/Tetra CFD, Optimus (Design of Experiments and Optimization software). Work Experience:

Principal Engineer, Commercial Vehicle Systems, Meritor (formerly Rockwell International) 1995 – May 2020

• Positions previously held: Sr. Design Engineer, Project Engineer, Sr. Project Engineer

• Vehicle dynamics simulation: prediction of vehicle ride, handling, and durability performance of commercial vehicles (tractor-semi-trailer combinations) and military trucks.

• Finite element analysis: stress analysis, structural dynamics, heat transfer.

• Computational fluid dynamics: convection and conduction heat transfer in disc brake rotors and pads, lubricant flow in truck axles, metal casting simulation (filling and solidification).

• Analytical road loads: prediction of dynamic loads on suspension components, design of new test procedures for the accelerated durability tests of vehicle suspension systems.

• Noise and vibration: modeling and simulation of noise and vibration issues such as brake noise, wheel shimmy, and drive train vibration.

• Active control systems: modeling and simulation of active vehicle control systems such as anti-lock braking systems, active suspensions, and vehicle dynamics control systems.

• Products supported: advocated simulation-driven design of chassis and suspensions, steering systems, axles, differentials, driveline, transmission, brakes, wheels and hubs.

• Training and technical support: served as internal consultant to division engineers in the areas of mechanical system dynamics, vehicle dynamics, modeling, and simulation.

• External communications: promoted visibility of the company’s technical capabilities by active participation in professional organizations and through publication of technical papers in industry seminars and conferences. Industry-recognized expert in multibody dynamics and ADAMS modeling and simulation of mechanical systems. Research Fellow, Mechanical Engineering and Applied Mechanics, University of Michigan 1993 – 1995

• Conducted research on the modeling of the behavior of rubber components in automotive suspension systems.

• Developed computer models of complete vehicle suspension systems for predicting the performance of the vehicle with respect to ride comfort, handling, and durability. Graduate Research Assistant, Mechanical Engineering Dept., University of California, Santa Barbara 1989 - 1993

• Developed numerical methods for the dynamic analysis of mechanical and structural systems

• Nonlinear finite element analysis of flexible multibody systems Education:

Master of Business Administration, Ross School of Business at the University of Michigan, 2008. Ph.D. Mechanical Engineering (Structural Dynamics), University of California, Santa Barbara, 1993. Ph.D. Dissertation: Forward and Inverse Dynamics of Flexible Multibody Systems M.S. Civil Engineering (Structures), University of Oklahoma, 1988, (4.0 GPA). M.S. Thesis: Vehicle-Guideway Interaction in Rigid Airport Pavements with Discontinuities B.S. Civil Engineering (cum laude), University of the Philippines, 1984. Honors/Awards/Patents:

• Engineer of the Year, ArvinMeritor, Inc., 2005.

• Elected Member, Chi Epsilon National Civil Engineering Honor Society (1988).

• 1993 JDSMC Best Paper Award, ASME Dynamic Systems and Control Division,

"Exponentially Stable Tracking Control for Multi-Joint Flexible-Link Manipulators", (co- authored with B. Paden, D. Chen and E. Bayo).

• Best Paper Award, 23rd Biennial ASME Mechanisms Conference, Minneapolis, Minnesota, September 1994, "Augmented Lagrangian and Projection Methods for Constrained Multibody Dynamics ", (co-authored with E. Bayo).

• Technical Achievement Award, Rockwell International, Automotive Division, 1996.

• Technical Achievement Award, ArvinMeritor Inc., 2001.

• U.S. Patent No. 6208240-B1, “Front Axle Misalignment Sensor”, 2001. Sample Refereed Journal Publications:

• A. Kukreti, M. Taheri, and R. Ledesma, "Dynamic Analysis of Rigid Airport Pavements with Discontinuities," ASCE Journal of Transportation Engineering, Vol. 118, No. 3, pages 341- 366, 1992.

• R. Ledesma and E. Bayo, "A Non-Recursive Lagrangian Approach to the Inverse Dynamics of Flexible Multibody Systems: The Planar Case," International Journal for Numerical Methods in Engineering, Vol. 36, No. 16, pages 2725-2741, 1993.

• R. Ledesma, S. Devasia, and E. Bayo, "Inverse Dynamics of Spatial Open-Chain Flexible Manipulators with Lumped and Distributed Actuators," Journal of Robotic Systems, Vol. 11, No. 4, pages 327-338, 1994.

• R. Ledesma and E. Bayo, "A Lagrangian Approach to the Non-Causal Inverse Dynamics of Flexible Multibody Systems: The Three-Dimensional Case," International Journal for Numerical Methods in Engineering, Vol. 37, pages 3433-3361, 1994.

• E. Bayo and R. Ledesma, "Augmented Lagrangian and Mass-Orthogonal Projection Methods for Constrained Multibody Dynamics", Nonlinear Dynamics, Vol. 9, pages 113-130, 1996.

• R. Ledesma, Z.D. Ma, G. Hulbert, A. Wineman, "A Nonlinear Viscoelastic Bushing Element in Multibody Dynamics," Computational Mechanics, Vol. 17, pages 287-296, 1996.

• Numerous SAE Papers can be searched at www.sae.org Professional Accreditations and Affiliations:

• Licensed Civil Engineer, Republic of the Philippines (License No. 00041099)

• Professional Engineer, State of Michigan (License No. 620*******)

• Society of Automotive Engineers, International

• American Society of Mechanical Engineers

• Certified Six Sigma Green Belt

Conference Presentations:

• 1994 ASME Mechanisms Conference, “Augmented Lagrangian and Projection Methods for Constrained Multibody Dynamics”

• 1996 ADAMS User Conference, “Modeling Friction-Induced Dynamic Instabilities Using Flexible Multibody Dynamics”

• 1997 ADAMS User Conference, “Transient Analysis of an Integrated Powertrain and Suspension System”

• 1998 ASME ETCE Conference, “Effect of Chassis Frame Compliance on Heavy Truck Ride Quality”

• 1998 SAE Truck & Bus, “Heavy and Medium Duty Vehicle Powertrain Virtual Prototyping”

• 1999 SAE Truck & Bus, “Heavy and Medium Duty Vehicle Suspension-Related Performance Issues”

• 2000 SAE Automotive Conference, “Effect of Tire Stiffness Parameters on Medium Duty Truck Handling”

• 2001 SAE Truck & Bus, “Effect of Kingpin Inclination and Wheel Offset on Medium Duty Truck Handling”

• 2002 SAE Truck & Bus, “Ride Performance of Trailer Suspension Systems”

• 2003 ADAMS User Conference, “Modeling Frequency-Dependent Stiffness and Damping in Rubber Bushings with Fractional Derivatives”

• 2004 ADAMS User Conference, “Wheel Shimmy in Heavy Duty Trucks: Using Designed Numerical Experiments to Determine a Robust Solution”

• 2004 SAE Truck & Bus, “Design of Experiments and Design Optimization of the Suspension System of a Tractor-Semi-Trailer Combination”

• 2005 SAE Truck & Bus, “Accelerated Durability Tests for Commercial Vehicle Suspension Components

• 2007 SAE NVH Conference, “A Simple Model for the Simulation of Low-Frequency Disc Brake Noise”

• 2011 MSC Software Conference, “Designing Anti-Lock Braking Systems for Commercial Vehicles Using Sliding Mode Control and an Adaptive Nonlinear Observer"

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