Reconfigurable Seat for Humvee Simulator Lockheed Martin Group #8 Shannon Whyms Jeremy Riggs Ryan Hendrickson Mei-Ling Liber

Overview Project Scope Current Design and Problem Areas Product Specifications Concept Generation and Design Analysis Materials Future Plans

Project Scope The goal of this project is to design and build a seat for the Virtual Combat Convoy Trainer (VCCT). A reconfigurable seat design for converting the trainer between HMMWV & truck configurations.

Current Design Two-piece seat with reconfigurable cushions Prong and slot design Crank for height adjustment

Problem Areas Current design has had structural problems and is fairly complex Deformation of back support after repeated use Vertical height adjustment is tedious

Product Specifications Reconfigurable Withstand a 300N (70 lb) horizontal load Fore and aft adjustment Height adjustment Seat and/or seatbelt should be symmetrical Target weight of the seat is ~ N (20- 25lbs)

Concept Generation One-piece seat Addition of latches Hydraulic Piston for height adjustment Stationary seatbelt placement Rails address fore and aft adjustment

Concept Design Fully assembled seat Seat and latch assembly only Back view

Concept Design Gas Spring Lift Female Latch Box assembly with rails and male latch

Analysis & Assumptions Seat can be modeled as a rigid body Latches are crash tested Seat rails are sufficiently sturdy Comparison between original and concept design using finite element analysis

Shear Analysis Point of failure: Latch Bolts Applied force at the seatback translates to a shear force at the latches Total weight translates to a compression force at the latches Once shear and compressive forces are known, bolts can be sized

Bolts Grade 5 Medium Carbon Steel Yield Strength: 92,000 psi Shear Strength: 55,200 psi Factor of Safety: 2 Allowable Yield Strength: 46,000 psi Allowable Shear Strength: 27,600 psi Bolt Size: ¼ -20

Finite Element Analysis Original Prong Design Our Concept

Materials Frame of chair: Low carbon AISI C-1008 Covering of chair: Foam Padding Screws/pins: Grade 5 Medium Carbon Steel Box: OEM Gas Lift: OEM

Cost Analysis Procured Items PartVendorQuantityCostSubtotal PistonSwivel Chair Parts1$62.33 BoltBolt Depot1$16.57 Latch SetChevrolet4$81.41$ SeatbeltJunkyard1$0.50 Steel (seat)Speedy Metals4$50.00$ Custom Services WeldingCOE Machine Shop N/A $0.00 UpholsteryTBD $300.00$300 Total Cost $905.02

Future Plans Analysis Analytical calculation of force required for unlatching Fatigue analysis on joints Overall Sourcing and procurement of materials and parts Manufacturing and assembly

Acknowledgements Lockheed Martin Jeff Payne David Bogle Dr. P.J. Hollis

References Hibbeler, R.C., “Statics and Mechanics of Materials,” Second Edition, Prentice-Hall, Inc., Boston, Copyright Norton, Robert, “Machine Design: An Integrated Approach,” Third Edition, Pearson Prentice Hall, Upper Saddle River, Copyright 2004.