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This paper presents the design of two cleaning systems following systems engineering design approach. An in situ cleaning system was designed for removing engine oil stains and metal swarf and shavings that adhere to rollers of conveying lines which convey cylinder head as well as other heavy engine components. The other system was to clear and collect metal debris accumulated in the grooves of an engine block internal assembly line. Prototypes were fabricated for the designed cleaning equipment for further testing and assessment. In the system engineering design process, preliminary, intermediate, and detailed design were conducted following an identification of the design problem, within that process a sequence of tasks such as synthesis, analysis, prototyping, and assessment were completed.

The moisture/water absorption and microvoids/cracks progression are two well-understood mechanisms that have significant degradation effects on the mechanical properties/behaviors of the polymer-based composites. To theoretically investigate the effects of above two mechanisms, we develop a simple fiber reinforced polymer composites model by employing the internal state variable (ISV) theory. The water content and the anisotropically distributed damage of the composites are considered as two ISVs (the water content is described by a scalar variable and the damage is defined as a second order tensor) whose histories are governed by two specific physically-based evolution equations. The proposed model can be easily cast into a general theoretical framework to capture more polymer composites behaviors such as viscoelasticity, viscoplasticity and the thermal effect.