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In this paper a method is presented for predicting the compressive strength of unidirectional fibre-reinforced plastics. Initial fibre misalignment and nonlinear shear response are included in the model which is based on a combination of other published methods. Predictions are shown to compare well with test data from an improved test method for carbon fibre-reinforced materials; one with an epoxy matrix and one with a PEEK matrix. Acceptable predictions are shown to depend on an appropriate assessment for fibre misalignment. The influence on compressive strength of moisture uptake by the composite was seen to be correctly predicted by the model.

The current experimental study at Mach 7 was carried out to investigate the viscous flow effects in a scramjet inlet with a fixed geometry operating at Mach 7.5-8. To reduce the risk of inlet unstart, an optional passive boundarylayer bleed was integrated at the throat and tested for different bleed dimensions. The passive bleed significantly reduces the lip-shock-induced separation bubble on the ramp. But the correct location of the bleed gap is important for the reduction of the separation bubble. To investigate the compression behavior, different backpressures were applied and the effects on the internal flow structure were analyzed by means of static pressure along the isolator and pitot pressure profiles at the exit of the isolator. Because the reference configuration has a very small internal contraction ratio to guarantee self-starting, the internal compression ratio was increased in three steps by means of additional sidewall compression along the internal flowpath. This includes internal contraction ratios above the starting limit. This measure led to a significant increase of the static pressure ratio at the end of the isolator. The complex flow structures are explained by means of detailed static and pitot pressure plots. Nomenclature= mass flow, kgs 1 p = pressure, Nm 2 q = dynamic pressure, Nm 2 R = specific gas constant for air 287.15, Jkg 1 K 1 Re = Reynolds number T = temperature, K = calibration value = throttle degree, 1 A mfm;th A 1 0 100% = density, kgm 3 = total pressure recovery Subscripts CC = combustion chamber entry condition mfm = mass flow meter SW = sidewall compression inlays 1 and 2 th = throat t0 = wind-tunnel total conditions w = wall 0 = freestream plane ahead of the inlet 1 = wind-tunnel freestream conditions