Ford Aerospace & Communications Corporation

Diamond Walnut Growers

Thomas J DeLacy

Robert W Cribbs

Billy L Lamb

George F Carroll

John R Bingham

Method and apparatus are disclosed for inducing dimensional stability in cured composite structures using acoustic emission analysis to identify the appropriate level and extent of coincident thermal conditioning. Temperature of the composite structure is lowered at a bounded rate to a minimum temperature typical of the intended operating environment. Passive stress wave acoustic emissions of the composite are analyzed to generate a signature of stress relaxation events over time. When the rate of stress relaxation events decreases below a predetermined percentage of the maximum rate, and remains below that level for a period of time sufficient to predict operational stability, thermal conditioning is terminated.

System for stabilizing dimensional properties of cured composite

Non-invasive and non-destructive apparatus and method for imaging, recording, and comparing the mass density distributions and thicknesses of test specimens (19F, 19B). A source of medium-to-high-energy photons (3) directs a photon beam (4) at an electron source (17) comprised of high atomic number material, which emits in response thereto electrons (9F, 9B), some of which are not absorbed and not widely scattered by the test specimens (19F, 19B), but are transmitted therethrough and captured on one or more photographic films (15F, 15B) in contact with said specimens (19F, 19B). Net recorded film (15F, 15B) densities are in inverse relation to the mass density distribution of the corresponding test specimen (19F, 19B). A filter (5) is interposed between the photon source (3) and the capture film (15B) when back emission imaging (B) is employed. The filter (5) is optional when forward emission imaging (F) is used. The filter (5) absorbs photons (4) that have an energy sufficiently low to create an unwanted X-ray response on the capture film (15F, 15B) within the period required for the desired electron (9F, 9B) imaging.

Non-destructive testing by stimulated electron emission capture

A novel particle sorting system based on vibrations induced by impact against a strike plate is disclosed, wherein two strike plates in succession are used, the first to absorb kinetic energy from certain particles on a preferential basis due to particle composition, and the second to absorb the residual kinetic energy for analysis. Vibrations arising in the second strike plate due to particle impact which meet preset criteria corresponding to undesired particles are used to actuate an ejection system which sends an impulse to the offending particle, deflecting it from its otherwise undisturbed trajectory. Also disclosed is an analyzing circuit which combines two or more waveform features of the vibration signal in an algorithm such as a ratio, to provide an unusually high sensitivity for discrimination among the particles. In addition, the need to form a single file of particles before they can be put through the system is avoided by the use of a curved surface to convert the particle mixture to a free-falling monolayer, and by sensing impacts of the second strike plate in a region-specific manner.

Method and apparatus for particle sorting by vibration analysis

Methods and apparatus are disclosed for monitoring and controlling potential residual stress relief mechanisms in composite epoxy resin materials. Passive and injected, or active, acoustic signals originating in or propagated through a specimen material during the formation process produce signatures identifiable with known residual stress relief mechanisms. Real-time control of material temperature and external pressure during formation in response to acoustic signals measured or observed in relation to desired acoustic signature minimizes formation of undesired material properties.

Method and apparatus for non-destructive testing of composite materials

Described herein is a microwave radar system which employs heterodyned swept frequency at approximately two millisecond sweep intervals. The power source is a reliable solid state, low power device such as a Gunn diode. The heterodyned difference frequency signals are converted to digital form, transformed into the frequency domain by means of a Fourier power transform, and then averaged by computer processing. Performing the Fourier power transform before averaging enables the processing of quasi-incoherent data whereby signal-to-noise ratio improvement is a function of the square root of the average number of samples taken. High-speed processing is used to off-set the loss of statistical averaging of phase-coherent data which cannot be preserved because of target motion. Thus, the sequence of the power transform allows phase-less averaging over the entire collection period. Complementary elements including signal isolation and stability, through interdependent design features of the antenna and circulator, permit the use of low-power CW radar which minimizes danger to ecology and human safety. Thus, the invention has particular applicability to the analysis of clouds, the extraction of range and thickness data of clouds, and the presence and velocity of rainfall. The invention can be used for point targets as well. Algorithms are built into the computer to compensate for various factors such as wind, temperature, and the nature of scattering nuclei.

Growing community of inventors

Los Altos, CA, United States of America

Thomas J DeLacy