Engineering topics
Publications and source records attributed to Ehret, R. M..
Improved sewing technique for high-temperature insulating blankets prevents stitch failure in hot, turbulent environments. Standard lockstitch modified to isolate single-stitch failures. Bobbin thread kept at blanket surface. Silicone adhesive applied to all bobbin/needle intersections, so failure at one point will not propagate along thread. Suitable for use in aerodynamic and other applications where there is turbulence.
A design allowables test program was conducted on Celion 6000/LARC-160 graphite polyimide composite to establish material performance over a 116 K (-250 F) to 589 K (600 F) temperature range. Tension, compression, in-plane shear and short beam shear properties were determined for uniaxial, quasi-isotropic and + or - 45 deg laminates. Effects of thermal aging and moisture saturation on mechanical properties were also evaluated. Celion 6000/LARC-160 graphite/polyimide can be considered an acceptable material system for structural applications to 589 K (600 F).
The concepts explored in a state of the art review of those engineering fracture mechanics considered most applicable to the space shuttle vehicle include fracture toughness, precritical flaw growth, failure mechanisms, inspection methods (including proof test logic), and crack growth predictive analysis techniques.
Method uses assembly consisting of single pictorial display showing cutaway view of assembly, subassemblies identified by name and materials, and processes identified by both specification and commercial design. Display is used in engineering, manufacturing, and personnel training.