Kerry J. Mulligan

A novel mechanical lung model of pulmonary diseases to assist with teaching and training

BackgroundA design concept of low-cost, simple, fully mechanical model of a mechanically ventilated, passively breathing lung is developed. An example model is built to simulate a patient under mechanical ventilation with accurate volumes and compliances, while connected directly to a ventilator.MethodsThe lung is modelled with multiple units, represented by rubber bellows, with adjustable weights placed on bellows to simulate compartments of different superimposed pressure and compliance, as well as different levels of lung disease, such as Acute Respiratory Distress Syndrome (ARDS). The model was directly connected to a ventilator and the resulting pressure volume curves recorded.ResultsThe model effectively captures the fundamental lung dynamics for a variety of conditions, and showed the effects of different ventilator settings. It was particularly effective at showing the impact of Positive End Expiratory Pressure (PEEP) therapy on lung recruitment to improve oxygenation, a particulary difficult dynamic to capture.ConclusionApplication of PEEP therapy is difficult to teach and demonstrate clearly. Therefore, the model provide opportunity to train, teach, and aid further understanding of lung mechanics and the treatment of lung diseases in critical care, such as ARDS and asthma. Finally, the models pure mechanical nature and accurate lung volumes mean that all results are both clearly visible and thus intuitively simple to grasp.

A simple hybrid testing approach for dynamic analysis of civil structural control devices

This paper presents a simple and robust hybrid test system and outlines solutions to the major issues faced in developing any hybrid system. The overall approach is centred on the dSpace™ real-time control system development tool. The final system readily accommodates non-linear-single and multi-degree-of-freedom models and an operating bandwidth of 1 kHz. Experimental outcomes are based on studies of a linear single degree of freedom structure and a non-linear rocking wall system that includes impact loads and timing subject to random ground motions. The results illustrate the potential outcomes of full scale experiments but at a cost-effective level.

Re-Shaping Semi-Active Structural Response Via Simple Applications of Embedded Computation, Sensors and Valves

Semi-active dampers and actuators hold significant promise for their ability to add supplemental damping and reduce structural response, particularly under earthquake loading. Novel devices utilizing off the shelf components and control systems are used to modify structural response. Devices are presented from design, modeling, analysis and validation via hybrid testing and experimental shake table results. All cases are compared with independent analytical predictions based on first principles analysis.Copyright