Testing of spacecraft attitude and orbit control systems

The testing of Spacecraft Attitude and Orbit Control Subsystems is described from the early design up to in-flight, inclusive. Main topics dealt with are: description of three generic AOCS test classes, model philosophy, standardization, subsystem static test methods, subsystem dynamic test methods, generic test equipment and test facilities....

Influence of environments on constant displacement stress corrosion crack growth in high strength aluminium alloys

An experimental investigation was carried out into the applicability of various corrosive environments for stress corrosion crack propagation testing of high strength aluminium alloys using double cantilever beam specimens. Testing under atmospheric conditions was used as a reference. It was found that stress corrosion crack growth under...

Operating conditions and materials selection and development in gas turbines

This paper consists of two parts. In the first part, concerning operational conditions in gas turbines, the following topics are covered: - the magnitude of temperatures, temperature profiles, and stresses in various components - transient temperature conditions, occuring as a result of e.g. throttle setting changes and affecting thermal fatigue...

Influence of environmental ageing and displacement rate on crack resistance of adhesives, as determined on adhesive bonded TDCB-specimens

Fracture toughness measurements were carried out to test the ageing behaviour of three adhesives in different environments. It was possible to compare and evaluate adhesives and surface pretreatments. It is doubtful whether the derived R-curves could be used for residual strength calculations in certain environments. Phosphoric acid anodizing...

Environmental fatigue crack propagation in metal/composite laminates

Flight simulation fatigue crack propagation tests with gust spectrum loading were carried out on 2024-T3/carbon-epoxy, 7475-T76l/carbon-epoxy and Ti-6Al-4V/carbon-epoxy laminates with nominal weight savings of -30% as compared to equivalent 2024-T3 panels. The performance of the 2024-T3/carbon-epoxy laminates was much superior to those of the...

Engineering application of fracture mechanics to flight simulation fatigue crack propagation

Environmental effects on crack grwoth in flight-simulation tests on 2024-T3 and 7075-T6 material Supplement: Compilation of test data from an investigation on the effect of environment on crack growth under flight-simulation loading

Flight-simulation tests based on a standardized gust load spectrum were carried out in normal air, very dry air and salt water. Specimen thicknesses were t = 2 mm and t = 10 mm, mean stress in flight was 70 or 55 MN/m². In all cases a significant effect of the environment was found. Fatigue lives for t = 10 ram were much shorter than for t = 2...

Residual strength of the aluminium alloy 7475-T76 at low temperatures

Residual strength tests have heen performed, on 300 mm wide centrecracked panels of various thicknesses, at room temperature and at -50 C. During the tests, stable crack growth was filmed and recorded with the electric potential method. Fracture toughness was determined using the method of Feddersen.

Study of the growth of stress corrosion cracks in the aluminum alloy 7075. Part III: Continuation of the investigation on the influence and the role of the corrosion potential and the halide anion

SEN specimens of 70T5 alloy loaded in bending have been used to determine time to failure and the crack propagation rate as a function of K, the stress intensity factor, and of the electrical potential in 3 wt % aqueous solutions of NaCl, NaBr and Nal with p values of 3 and 7. The SC tests were supplemented by potentio-kinetic polarization tests...

High temperature gas turbine materials

The requirements and problems of high temperature materials in gas turbines are reviewed, with specific reference to turbine discs, blades, vanes and combustion cans. The mechanical and environmental property requirements of these components are discussed, followed by an overview of the types of materials used. Lastly, there is a summary of the...

Advances in chloride diffusion of concrete exposed to marine field environment

For elaborating the research significance, goal, content and representative results of the concrete marine field exposure experiments all over the world, we have collected a large number of research literature since 1905. The longest exposure test for concrete has reached 62 years and, most importantly, concrete exposure experiments have made...