Theoretical source rupture and wave propagation models are used to simulate strong motion acceleration time histories. the synthetic acceleration records are computed based on modal superposition, and include both p-sv and sh wave motion to frequencies up to ten hertz. in particular, strong ground… More

An analytical model for reinforced concrete is proposed which relates material degradation of the concrete to strains in the reinforcement. the reinforcement will be distributed through the concrete to produce a homogeneous material. the model will distinguish between tension and shear crack… More

The proposed project will determine the feasibility of using a centralized function for finite element models of usaf aircraft. this objective will be achieved through characterization of finite element model usage, development and comparison of approaches to model commonality, and creation and… More

Failure analysis associates (faaa) proposes to evaluate a nonlinear viscoelastic constitutive law for modeling the response of solid rocket propellant. this constitutive law, which is based on modified coleman-noll model, is known as the burke model, after its developer, dr michael a burke of faaa.… More

It is proposed that a previous fracture mechanics life technology survey prepared by failure analysis associates for nasa be updated and extended to a survey for crack growth in submarine hull structural details. computer programs from the survey that survive a screening will be evaluated in detail.… More

The proposed program would develop a multijunction photovoltaic system based on achieving spectrum splitting by passing concentrated sunlight thorugh a prism. the overall objective of the phase i effort is to demonstate the feasibility of a prism/spectrumsplitting multijunction concept for… More

This project will demonstrate a technique for rapid surveillance of the micro-structures and nonequilibrium phase chemistry obtainable through rapid solidification processing of alloy systems. the method will allow an efficient identification and analysis of the nonequilibrium phase chemistries… More

A multi-frequency electromagnetic test method is proposed to sort fasely marked steel fasteners. testing will consist of measuring the impedance of a probe at two different frequencies and two different magnetic field strengths when in close proximity to the fastener. the 8 dimensional state vector… More

The flexible eddy-current probe array concept, developed by failure analysis associates , has introduced a new approach to eddy-current testing. coverage of the test area can be accomplished, without scanning, by placing an array of probes, fabricated on a thin flexible substrate, against the test… More

Magnesium alloys are a very attractive structural material for aerospace applications due to their high specific strength and stiffness. one glaring problem with these alloys is their very poor resistance to corrosion, particularly when exposed to chloridecontaining environments. if magnesium alloys… More

The objective of phase i is to develop a special reliability analysis algorithm for diesel engines that accounts for the complex factors and severe environmental conditions experienced in military applications. a reliability, availability, maintainability (ram) monte carlo simulation approach is… More

Most of the ultrasonic scanning systems in service or being installed at dod facilities offer some means of recording inspection data. however, the advantages of this capability aren't being fully realized because the storage media and data archival formats differ from system to system. this lack of… More

The objective of phase i is to develop technology for a simple jar-opening device that allows the elderly or handicapped to open threaded or twist-off jar lids easily and safely. the device will consist of a compact, electrically powered appliance that will grasp both jar and lid and unscrew the lid… More

This sbir poses a complex and multifaceted problem; the statistical analysis of real-life overhaul and failure data, and the development of a mathematical model of the most critical failure processes. this involves required expertise in the analysis of incomplete, nonhomogeneous data sets, the… More

There exists a need for field evaluation techniques on dam- aged rairoad tank cars, a large proportion of which are of insulated design consisting of an outer shell, an insula- tion space, and an inner liner. these cars are used to haulmany potentially hazardous materials and chemicals, and… More

In this project, failure analysis associates (faaa) proposes to evaluate and develop techniques that may provide the basis for using ct data to detect and assess the nature of sub-pixel features in rocket motor components. faaa plans to apply nde data analysis and display technology, that we have… More

The long-term objective of this program is to provide a superior, low-noble-metal-content alloy system having metal/ceramics compatibility and biocompatibility at a lowercost than the present high-noble alloys. the combination ofthe performance and cost factors of this alloy system will allow it to… More

The continued progress being made in liquid-metal-cooled nuclear reactors requires a capability to monitor and inspect reactor internals. since the 1960s research in ultrasonic imaging has been pursued at a somewhat leisurely pace. simple sonic echo ranging has been the principle relied upon to… More

Occupant protection in vehicular side impact crashes is an important theme of the '90s for the department of transportation, for automakers, and for independent researchers. development of occupant protection methods requires accurate measurement of contact velocity in side impact tests. microwave… More

It is proposed that data be collected to assess the feasibility of adapting a variety of electrical accident investigation techniques to aircraft accident investigation. some of the candidate techniques include: filament deformation and fracture in filament lamps due to impact; demagnetization of… More