This paper presents an adaptive sliding mode control structure of underactuated unmanned surface vessel systems under parametric uncertainty. The primary motivation in this research is to compensate for disturbances related to the added hydrodynamic forces and moment in the nonlinear control of a three degree-of-freedom marine vessel. The novelty of this work is the tracking robustness and the compensation for uncertainties common to surface vessels. The first work is to divide the dynamic model of the system into the ship rigid-body terms and added terms induced by hydrodynamics. A sliding-mode controller is designed to force the error trajectory into the sliding surface, which produces a robust tracking result in a finite time. For the parametric uncertainties in the dynamic model, an adaptive controller is designed to compensate using a projection-based adaptation law. After combining these two control schemes, a closed-loop controller designed by a Lyapunov-based control approach over feedback linearization is appropriately designed to yield the nonlinear tracking system bounded in the presence of uncertainties. The mathematical proof shows that a stable tracking result in the sense of Lyapunov-type stability is achieved. Numerical simulation results are shown to demonstrate the validity of these proposed controllers.

Filament wound composite pressure vessel with thin-wall alloy liner might exist local buckling during manufacture and in service, this phenomenon have great influence on the security and service lifetime of pressure vessel. AE (acoustic emission) technique is employed to monitor the damage progression of the vessel during hydraulic pressure experiment. Two sensors of acoustic emission (AE) were attached to front dome and cylinder to monitoring the behavior of the vessel bearing maximum 4.5MPa water pressure during loading, keeping load and unloading. Meanwhile ten strain gauges were bonded to front dome, equator and cylinder of the outer surface by meridian and hoop direction respectively in order to monitor the vessel deformation characters. Analysis show that strain gauges is suitable for evaluate deformation character of the outer surface of the vessel. Analysis indicated AE is more suitable to monitoring the damage propagation of the vessel. AE analysis explained the local buckling of inner thin-wall liner.

Impact damage has been identified as a critical form of defect that constantly threatens the reliability of composite structures, such as those used in aircrafts and naval vessels. Low energy impacts can introduce barely visible damage and cause structural degradation. Therefore, efficient structural health monitoring methods, which can accurately detect, quantify, and localize impact damage in complex composite structures, are required. In this paper a novel damage detection methodology is demonstrated for monitoring and quantifying the impact damage propagation. Statistical feature matrices, composed of features extracted from the time and frequency domains, are developed. Kernel Principal Component Analysis (KPCA) is used to compress and classify the statistical feature matrices. Compared with traditional PCA algorithm, KPCA method shows better feature clustering and damage quantification capabilities. A new damage index, formulated using Mahalanobis distance, is defined to quantify impact damage. The developed methodology has been validated using low velocity impact experiments with a sandwich composite wing.

The concept of self-healing materials has gained widespread acceptance in the research community. Over recent years a diverse array of bio-inspired self-healing concepts, from solid-state diffusion to liquid-phase healing in a broad range of engineering materials, embracing ceramics, polymers and fibre reinforced polymer composite materials have been proposed in the open literature. In this research study the liquid-phase healing of operational damage, namely impact damage, is being addressed. The challenge of self-healing advanced fibre reinforced polymer composites is ensuring healing success without degrading the host composite’s performance, a problem not encountered in the self-healing of generic polymeric systems. In the genre of self-healing fibre reinforced composite materials, autonomous healing has been undertaken by a healing medium already located within the damage zone and released through the damage site either passively or actively through human invention. This approach requires the ‘engineering’ control of the storage medium’s toughness for release and the development of bespoke resin chemistries to be compatible with the manufacturing route, to remain active whilst latent and then to recover full mechanical performance once a damage event occurs. This study has generated a proof of concept whereby the healing medium is only deployed to the damage site once a sensor has been triggered. In essence this study aims to develop stimuli triggered deployment of a healing medium held remotely in a storage reservoir to repair impact damage to a composite material. The principle of the concept is revolves around the ability of a reservoir to deliver a healing medium to a damage site via a network of vessels contained in the centerline of the composite laminate. A Labview controlled peristaltic pressure rig containing the reservoirs for the resin and hardener, their independent pumps, pressure gauges, control switches and indicators was developed. Through the application of an impact event successfully deliver and subsequent healing of the damage event was achieved showing the potential of this concept for minimising parasitic mass and maximising healing potential in fibre reinforced composite materials.

This film nitinol produced by sputter deposition was used in the design of microstents intended to treat small vessel aneurysms. Thin film microstents were fabricated by “hot-target” DC sputter deposition. Both stress-strain curves and DSC curves were generated for the film used to fabricate stents. The films used for stents had an A f temperatures of approximately 36 degrees allowing for body activated response from a micro-catheter. The ten micron film was only slightly radio-opaque; thus, a Td marker was attached to the stents to guide fluoroscopic delivery. Thin film microstents were tested in a flow loop with and without nitinol support skeletons to given additional radial support. Stents could be compressed into and easily delivery in < 3 Fr catheters. Theoretical frictional and wall drag forces on a thin film nitinol small vessel vascular stent were calculated and the radial force exerted by thin film stents was evaluated theoretically and experimentally. In-vivo studies in swine confirmed that thin film nitinol microstents could be deployed accurately and consistently in the swine cranial vasculature.