High-Build Plural Polyurea Protection for Vehicle Torsion Bars: Final Report

Abstract

Torsion bars have long been used as part of the suspension system in US Army ground combat vehicles. Torsion bars occasionally suffer catastrophic failures when the load exceeds the tolerance of the bar or due to failure from reduction in critical cross-sectional diameter due to fatigue crack growth. Corrosion can exacerbate the load problem by introducing defect sites for fatigue cracking initiation. The current corrosion mitigation strategy for torsion bars is to clean, shot peen, prime, and apply an electrical insulating polyethylene tape wrap to the torsion bars. The tape damages easily, degrades over time, is not easily removed, and is typically hastily repaired in place. The USMC Amphibious Assault Vehicle (AAV) uses a plural high-build polyurea (HBP) system as an alternative to the polyethylene tape wrapping. This system significantly improved corrosion resistance on the AAV bars versus the original tape, but did not provide a ready in-field capability for touch-up to damaged areas. This study investigates the use of improved and competitive HBP systems on torsion bars for the M2 Bradley Fighting Vehicle and the M1 Abrams main battle tank. Validation of the application and in-field touch-up procedures is discussed, as well as tests for impingement, cure, adhesion, and solvent resistance. Corrosion experiments are performed on test coupons in salt fog and accelerated cyclic corrosion, and on torsion bars placed in outdoor exposure at Cape Canaveral Air Force Station. Two complete sets of torsion bars each for Bradley and Abrams vehicles are fielded as demonstrations. Finally, a certified process is established using the objective quality evidence captured during the application processes.

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Document Details

Document Type
Technical Report
Publication Date
Jun 18, 2020
Accession Number
AD1102833

Entities

People

  • Brian E. Placzankis
  • Thomas A. Considine
  • Thomas E. Braswell

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Human Systems
  • Space

DTIC Thesaurus Topics

  • Adhesion
  • Air Force
  • Amphibious Operations
  • Armored Personnel Carriers
  • Corrosion
  • Corrosion Resistance
  • Department Of Defense
  • Dielectric Polymers
  • Environment
  • Impact Tests
  • Infantry Fighting Vehicles
  • Materials
  • Resistance
  • Shot Peening
  • Standards
  • Torsion Bars
  • Warfare

Fields of Study

  • Engineering

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Military Science
  • Surface Coatings Technology.

Technology Areas

  • Microelectronics