To: Chief Engineer Joel Barnett

ME243 Inc VUSE Center for Intelligent Mechatronics Proposal to Strain Energy Accumulator

Abdullah Zainal Abidin Hafizah Sinin Karl Brandt Danielle Patelis Oliver Tan

Date: 3/26/09 Technical Abstract: The project team will design and experimentally implement a high energy density hydraulic accumulator using strain energy. The project will extend the energy storage capacity of traditional accumulators and focus not on stabilizing flow but rather on storing large amounts of hydraulic energy with a high energy density. The intended application is in regenerative braking in series or parallel hybrid mid-sized passenger vehicles.

Customer:

The VUSE Center for Intelligent Mechatronics focuses on the design and control of electromechanical devices, with particular emphasis on the intersection of design and control. Much of their work is human-centered, including current research in anthropomorphic robotic upper and lower extremity prostheses; dynamic approaches to the control of robot biped locomotion; the use of biologically derived coordination influences for the control of legged locomotion in multi-legged robots; the development of high power-density actuation for human-scale robots; and the development of hybrid- FES systems to restore gait to spinal cord injured individuals.

Eric J. Barth, Ph. D. is the co-director of the VUSE Center for Intelligent Mechatronics at Vanderbilt University.

Project Description:

The project is to design and experiment on a, compact energy storage accumulator utilizing strain energy in non-conventional materials. The project will extend the energy storage capacity of traditional accumulators and focus not on stabilizing flow but rather on storing large amounts of hydraulic energy with a high energy density. The intended application is in regenerative braking in series or parallel hybrid mid-sized passenger vehicles. The goal is for a potential full scale prototype to be capable of storing up to 195 kJ of energy (3500 lbs vehicle at 35 mph) at a peak power of 390 kW (35 mph to 0 mph in 1 second). The project goal is to design, fabricate, and test a scaled prototype. The project requires an elastomer strain accumulator that has a low mechanical loss, high energy density, a resistance to chemical attack, large elongation, high tensile strength, good pliability in many temperature ranges, and it is easy to cast. Preliminary experimentation will determine what the design requirements are for an accumulator as a cylindrical elastomer. For running experiments we will be testing energy accumulation based on volumetric flow and pressure of the hydraulic fluid entering and exiting the accumulator. The experimental device that meets the systems capabilities will need to be designed and constructed. A fully automatic, electronic testing process will be added to augment the test process. The competition with this research is with gas bladder accumulators augmented with elastomeric foams. This design lowers losses due to heat buildup by 2-6.5% but still utilizes either a gas bladder which has inherent problems with gas diffusion or a piston which has inherent problems with frictional losses. Our design attempts to solve these problems by using a hydraulic bladder that stores energy in its strain. Losses will be lowered due to the incompressibility of hydraulic fluid and the presence of no sliding friction in the rolling process of bubble propagation in a cylindrical elastomer tube.

Statement of Work

The VUSE Center for Mechatronics requires the design, fabrication, and testing of a scaled prototype compact energy storage accumulator. The customer expects the group to extend the current state of knowledge in the use of strain energy storing materials. The group expects to devise an innovative design for the accumulator that will potentially be able to be implemented on a large scale application. The proposed high energy density accumulator will hopefully be utilized in hydraulic hybrid passenger vehicles that are used in city driving. Both parties expect a design that will solve the problem of high cost technology, increase efficiency and eliminate pre charge problems of previous accumulator technology.

Specific Task Descriptions

Literature Research Given the design specifications, research possible material to be used for the strain energy accumulator. Different materials are to be analyzed in a material science program for properties including, hardness, fatigue strength, modulus of elasticity and mechanical loss. After material selections, research possible designs of the accumulator that minimizes stress concentration and fatigue points.

Design the Test Bed Design the system that will have the capability to capture data when testing the accumulator’s properties. Develop a detailed list of every part of the system and start initial research of where to procure.

Prototype simulation After selecting possible materials and designs for the prototype, use computer programs (NasTran and PaTran) for FEA analysis and simulated material properties. Check the results of the FEA using empirical results. Estimate the percent elongation, energy storage capacity, and peak power capability. Pending the results of the simulation, modify the shape of the accumulator to eliminate stress points.

Material Procurement Research competitive prices for all materials that fit the system specifications. Order parts for the Test Bed and Material to fabricate the accumulator.

Fabricate Accumulator prototype and Test Bed Once material has been accrued, use ProE to model that cast for the accumulator. Construct mold with a rapid Prototype machine, and cast/ set the plastic accumulator. Next, assemble a sturdy test bed system to implement the previously computer simulated procedures.

Develop and Test Controller Create a LabView program to control and acquire data from the system.

Design Full scale SUV ptototype Pending the success of the prototype, design a full scale model of the accumulator to be tested in EPA driving scenarios.

Timeline (Gantt) Chart

A timeline of process used to work on this project is attached. This Gantt Chart shows the accomplished tasks as well as the projected tasks and their respective amount of completion times.

Staff Biographies Abdullah Zainal Abidin Senior Mechanical Engineer, Vanderbilt University

Abdullah is an international student from Malaysia, majoring in Mechanical Engineering with minors in Engineering Management and Mathematics. Abdullah is proficient in most software beneficiary to the strain energy accumulator project including Pro Engineer, and Microsoft projects. He is also relatively able in LabVIEW, JAVA, CORE, mathCAD, and Matlab. His minor in Engineering Management required for numerous involvement in projects resulting in valuable teamwork skills, designing skills, and project managing skills. Abdullah is also familiar with energy efficiency, having interned with PETRONAS Ltd. with the research division, under the power train department. Specifically, he assisted in analysis and CAE, studying the injection of fuel into the combustion chamber of a fuel-injected internal combustion engine using the Fluent software. Having interned with PETRONAS Ltd. throughout the summer of 2008, Abdullah is fairly able in thermodynamics and achieving maximum energy efficiency.

Hafizah Sinin Senior Electrical Engineer Vanderbilt University

Hafizah Sinin is a senior Electrical Engineering major at Vanderbilt University. In the summer of 2006, she did an independent study under the supervision of Prof. Mitch Wilkes and has gained knowledge on JAVA programming. She has taken series of courses in microelectronics and robotics as her major concentration, and also has a minor in Engineering Management. Throughout her coursework, she has learned using software such as PSPICE and TannerEDA for integrated circuit design and simulation. She is currently the grader for EECE 112: Circuits I, under the Department of Electrical Engineering and Computer Science.

Karl Brandt Senior Mechanical Engineer, Vanderbilt University

Karl is a senior engineering student at Vanderbilt University with a major in Mechanical Engineering, and a minor in Mathematics. His love for robotics has pushed him to take several undergraduate and graduate level robotics courses. Consequently, he is proficient in the art of designing, building, and adaptively controlling virtual robots. His favorite hobby is building and repairing computers and has done so for many friends and family members. During the summer of 2008, he helped research a carbon-reinforced composite material at Vanderbilt University for potential, future use in battleships. Since the summer of 2007, he also has been working for the Engineering Media Center at Vanderbilt University where he helps professors with the use of electronic equipment for classrooms.

Danielle Patelis Senior Mechanical Engineer, Vanderbilt University

Danielle Patelis is a senior engineering student at Vanderbilt University with a major in Mechanical Engineering.

Oliver Tan Senior Mechanical Engineer, Vanderbilt University Oliver is expected to graduate in May 2009 with a degree in Mechanical Engineering and a minor in Materials Science and Engineering. He has spent the last five years in California designing and building high performance full suspension mountain bikes for World Cup racing at both Specialized Bicycles Components and Chumba Racing L.L.C. Oliver enjoys HAAS CNC machining centers, fine “nickel stack” welds, Nastran customer service technicians, and testing data acquisition rigs.

Conclusion

This report is a preliminary report of the project involving a high-energy density accumulator. After the creation and full-fledged testing of the design, a final report will be provided that will show the direct, interpreted, and extrapolated results. Future application includes bladder redesign/scaling for full scale prototype. Also, the incorporation of hyperelasticity and solid collision into redesigned bladder FEA model.

Part 10: Potential Post Applications (Commercialization). The Phase 1 proposal shall forecast both the NASA and the non-NASA commercial potential of the project assuming success through Phase 2.The offeror, in the Phase 2 proposal, will be required to provide more detailed information regarding product development and potential markets (Section 3.3.4).