Mechanical Science and Engineering is an international, peer-reviewed open access journal dedicated to advancing research the field of mechanical engineering. The journal provides a rapid publication process to ensure wide dissemination of high-quality articles to scientists, professionals, and interested individuals worldwide. Our goal is to serve as an efficient, reliable, and trusted platform for scholars and readers, publishing cutting-edge research in the field.
Abstract: To address the urgent demands of emergency repair following subsea pipeline leaks, pipeline isolation technology has emerged as a key development direction for subsea intervention systems. As the core functional component of subsea pipeline plugging robot, elastomer seal plays a critical role in both setting reliability and sealing performance. This study first reviews the typical operational workflow of subsea pipeline plugging robot and elucidates the “self energisation” mechanism of elastomer seal under high-pressure internal fluids. On this basis, a mechanical model of elastomer seal is formulated, and a theoretical expression for the contact stress between Elastomer seal and the pipe wall was derived. Five commonly used hyperelastic constitutive models are then examined, and their strain-energy functions and engineering stress expressions under uniaxial tension are systematically derived to provide a theoretical basis for rubber-material parameter identification. Subsequently, numerical simulations of elastomer seal’s sealing behavior under the hydraulic actuation system are performed in ABAQUS, followed by pressure-penetration-based analyses of the contact stress distribution under the combined action of the setting load and internal fluid pressure. Comparison between theoretical predictions and finite-element results enables further refinement of the contact stress formula, allowing the corrected model to more accurately predict elastomer seal sealing performance under hydraulic driving. The findings provide a reliable analytical framework to support the structural optimization and engineering design of subsea pipeline isolation devices.Abstract: To address the urgent demands of emergency repair following subsea pipeline leaks, pipeline isolation technology has emerged as a key development direction for subsea intervention systems. As the core functional component of subsea pipeline plugging robot, elastomer seal plays a critical role in both setting reliability and sealing performance. Thi...Learn More
Abstract: A modified model-free adaptive control (MFAC) approach is proposed to address output fluctuation and overshoot problems existing in the prototype MFAC. Targeting a class of discrete-time nonlinear single-input single-output systems, historical input/output information is applied to construct explicit data model which is equivalent to the plant model in a real-time online manner. Control scheme is designed based on the data model such that model-free characteristic in control process is realized. A novel optimization index function is proposed by using the data model. An input compensation term is introduced on the basis of minimizing the tracking error in the prototype MFAC for restraining output response speed and softening control input. The input amplitude is reduced by the input compensation term for restraining output fluctuation and overshoot when the output change rate is too large. Adaptive matching between the output response and the control input is also realized. Numerical simulation results show that, compared with the prototype MFAC, the modified MFAC can significantly suppress the system output oscillation and overshoot under the same response time conditions. The output fluctuation of the closed-loop system is significantly reduced. The positive overshoot is reduced by about 10%, and the negative overshoot is effectively suppressed. The dynamic response of the closed-loop system is smoother and the operation is more stable.Abstract: A modified model-free adaptive control (MFAC) approach is proposed to address output fluctuation and overshoot problems existing in the prototype MFAC. Targeting a class of discrete-time nonlinear single-input single-output systems, historical input/output information is applied to construct explicit data model which is equivalent to the plant mode...Learn More
