A knowledge based expert system for the design and analysis of composite laminated struts is described. This system is part of a Composite Design EXpert (CODEX) system that not only performs analysis and design of composite laminated plates and struts, but also incorporates the modelling of uncertainties of information, definition and decision when assessing competing designs. The analysis part of the system is based on a minimum weight optimisation that satisfies the failure criteria of local buckling, overall buckling and maximum strain or maximum stress. Available in the system for analysis and assessment are seven types of strut shapes, six composite materials and aluminium alloy. Examples of strut design are carried out and assessed using this system.

The feasibility of using a single effective on-line control law to regulate the dynamic response of a jet engine throughout its flight envelope is of considerable importance. In this paper, a study was made to find such a single effective control law, which was able to regulate the dynamic responses of the linear, and ultimately the non-linear, model, throughout the engine’s entire operating range. This effective control law was obtained from solving a Linear Quadratic Problem (LQP) to obtain an optimal control law, a linear state feedback control.

Experiments were made on a two-dimensional low speed diffuser with passive control. The passive control consisted of porous surfaces made of holes/slots connected by a breather passage. Passive control postpones the stall and reduces buffet levels in the diffuser. This test confirms that passive controls to prevent flow separation are not restricted to transonic speeds.