Topic
Constrained-layer damping
About: Constrained-layer damping is a research topic. Over the lifetime, 795 publications have been published within this topic receiving 15758 citations.
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17 Sep 1995
4 citations
16 May 2005
TL;DR: In this paper, the optimal topology and the optimal constituent make-up of the constrained NRP layer was determined, where the volume fraction of the nanotubes in the constrained layer was optimized to maximize the system loss factor.
Abstract: Topology optimization has been successfully used for improving vibration damping in constrained layer damping structures with viscoelastic materials. Reinforcing carbon nanotubes in a polymer matrix greatly influences the mechanical properties of the polymer. Such nanotube-reinforced polymers (NRP) can be used to further enhance the damping properties of the constrained layer structures. The effects of nanotube inclusions on the damping properties of polymers and applicability of NRP for damping in structures have been studied previously. The inclusion of nanotubes into a polymer matrix provides new design variables in the topology optimization studies on such structures. The aim of this research is to determine the optimal topology and the optimal constituent make-up of the constrained NRP layer, where the volume fraction of the nanotubes in the constrained layer is optimized to maximize the system loss factor.
4 citations
01 Jan 2004
TL;DR: In this article, a numerical procedure for multi-disciplinary optimization of railway wheels, based on Design of Experiments (DOE) methodology and automated design, is presented, where the target is a wheel design that meets the requirements for fatigue strength, while minimizing the unsprung mass and rolling noise.
Abstract: A numerical procedure for multi-disciplinary optimization of railway wheels, based on Design of Experiments (DOE) methodology and automated design, is presented. The target is a wheel design that meets the requirements for fatigue strength, while minimizing the unsprung mass and rolling noise. A 3-level full factorial (3LFF) DOE is used to collect data points required to set up Response Surface Models (RSM) relating design and response variables in the design space. Computationally efficient simulations are thereafter performed using the RSM to identify the solution that best fits the design target. A demonstration example, including four geometric design variables in a parametric finite element (FE) model, is presented. The design variables are wheel radius, web thickness, lateral offset between rim and hub, and radii at the transitions rim/web and hub/web, but more variables (including material properties) can be added if needed. To improve further the performance of the wheel design, a constrained layer damping (CLD) treatment is applied on the web. For a given load case, compared to a reference wheel design without CLD, a combination of wheel shape and damping optimization leads to the conclusion that a reduction in the wheel component of A-weighted rolling noise of 11 dB can be achieved if a simultaneous increase in wheel mass of 14 kg is accepted.
4 citations
TL;DR: In this paper, a series of experimental investigations were presented on the vibration response of printed circuit boards treated with partial constrained damping layers, and it proves the CDL treatment having good effect on vibration response control of PCBs.
Abstract: Constrained damping layer (CDL) treatment has been an effective way to suppress vibration level of various structures. by introducing this method into the vibration control system of electronic equipments, this paper firstly discussed the dominant mechanism difference between free damping layer treatment and constrained damping layer treatment, Then base on the constrained layer damping layout optimization method in the vibration system of a rectangle thin board like PCB, a series of experimental investigations were presented on the vibration response of printed circuit boards treated with partial constrained damping layers. as a result, it proves the CDL treatment having good effect on vibration response control of PCBs.
4 citations
01 Jan 2011
TL;DR: In this article, the use of constrained layer visco-elastic damping on landing gear structural members is investigated for cantilever-loaded spring steel landing gear, and the performance of the damped system was evaluated for a 163 kg. aircraft with and without a Dyad 606 constrained layer damping treatment on the main and nose gear members.
Abstract: In aircraft, weight reduction represents one of the principal design goals, and landing gear design is no exception. Accounting for 3 – 7% of an aircraft’s weight, the landing gear is essentially dead weight after takeoff, and so reducing this weight becomes a priority of aircraft design. In addition to keeping the weight low, fixed gear designs can add significant drag if the design has not been optimized. The ideal landing gear should be low weight and low drag, but these criteria are typically at odds with a requirement for absorbing landing loads and preventing rebound. The use of constrained layer visco-elastic damping on landing gear structural members is a new application since historic use of constrained layer damping has been found on thin plate-like structures. Benefits of low weight and low drag are achievable using the conformal treatment, and this paper investigates specific constrained layer damping applications for cantilever-loaded spring steel landing gear. The design of the damped system considers the high stiffness and low surface area typical on a cantilever landing gear leg. Damping levels are examined for a 163 kg. aircraft with and without a Dyad 606 constrained layer damping treatment on the main and nose gear members. A 29% increase in damping was observed on the main landing gear, and a 25% increase in damping was observed on the nose gear when the treatment was applied. A full aircraft drop test is performed that showed inconclusive results in damping.
4 citations