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Vibration and noise reduction in structures can significantly enhance dynamic stability. In fact, exploitation of such mechanisms can lead to an improvement of aerodynamic performance in flight motions by aircrafts, hydrodynamic performance in ocean water navigation by ships or floating structures, as well as dynamic behavior of machine structures in production processes and systems. In this paper slip damping with layered viscoelastic beam-plate structures for dissipation of vibration energy in aircraft, hydrodynamic, and machine structures is investigated analytically. For this problem, a boundary value partial differential equation is formulated via contact mechanics. In particular, the effect of interfacial pressure distribution variation at the interface of the layered structures on the energy dissipation and logarithmic damping decrement with such layered structures is analyzed and presented for design applications. This allows for a better understanding of the selection process of viscoelastic damping materials for such structures. [DOI: 10.1115/1.2980368] Keywords: laminated viscoelastic beam plate, nonuniform interface pressure, slip, energy dissipation, logarithmic damping decrement

The dynamic response interaction of a vibrating offshore pipeline on a moving seabed is herein investigated where the pipeline is idealized as a beam vibrating on an elastic foundation. This problem is of relevance in offshore exploration where pipelines are laid either on or buried in the seabed. When such pipes carry oil and gas, the undulating topography of the sea floor and the internal motion of the fluid subject the entire structure to vibration due to bending forces and form the subject of our study. Our analysis revealed that in general, the seabed acts either as a damper or as a spring and in particular when we have sedimentation, the seabed geology permits the geomechanical property of the sediment cover to act only as a damper. As expected, external excitation will increase the response of these pipes for which an amplification factor has been derived. For soft beds, high transverse vibrations were dampened by increasing the internal fluid velocity whereas they became amplified for hard beds. These results are of contemporary interest in the oil/gas industry where deep sea exploration is now receiving significant attention. [DOI: 10.1115/1.2426994] Keywords: offshore pipeline, dynamic response, seabed, excitation of seabed, conveyance velocity of internal fluid