Computer programs for shielding problems in manned space vehicles

Computer programs for shielding problems in manned space vehicles - proton penetration code

Development of Replacement Heifers using Combinations of Three Forage Types and Feed Supplements (with or without Broiler Litter)

The proper management of replacement heifers is an essential component of successful cow/calf operations. The level of management and nutrition applied to replacement heifers as calves and yearlings can impact their subsequent reproductive performance and productivity

Tradeoff analysis of technology needs for public service helicopters

The design requirements for a family or type of Public Service Helicopter (PSH) is examined which will satisfy the needs of municipal and state governments in the following mission areas: Emergency Medical Service--Airborne Rescue Squad; Law Enforcement; Search and Rescue; and Environmental Control (Fire Fighting, Pollution, Resource Management). The report compares both design and performance requirements as specified by the PSH user's group against current technological capabilities, RTOPS and US Army LHX design requirements. The study explores various design trade-offs and options available to the aircraft designer/manufacturer in order to meet the several criteria specified by the PSH user's group. In addition, the report includes a brief assessment of the feasibility of employing certain advanced rotorcraft designs to meet the stringent combination of operational capabilities desired by the Public Service Helicopter Users

A combined experimental and modeling study of low velocity perforation of thin aluminum plates

This work conducts a combined experimental and modeling study of low velocity projectile perforation of thin AA5083-H116 aluminum plates. Experiments were performed in order to characterize the candidate material and calibrate simple and easy to implement empirical models for both the material response and ductile failure behavior. Quasi-static tensile tests were performed in order to investigate the Portevin-Le Chatelier effect common to 5xxx series aluminum as well as to calibrate a Ramberg-Osgood representation for the material stress-strain curve. The material response at strain rates up to and exceeding 104 s-1 was investigated by means of an electromagnetically driven ring expansion test, characterizing the potential strain rate sensitivity of the material. Additionally, the failure behavior and potential damage accumulation of the material were evaluated using an interrupted, multiple loading path strain-to-failure test, validating a Johnson-Cook failure model for use in numerical simulation. Low velocity ballistic impact and perforation experiments, investigating several specific mechanisms of deformation and failure, were conducted and modeled by implementing the developed material and failure model in 3D finite element simulations.Aerospace Engineerin