scholarly journals Experimental Characterization of a High-Damping Viscoelastic Material Enclosed in Carbon Fiber Reinforced Polymer Components

2020 ◽  
Vol 10 (18) ◽  
pp. 6193 ◽  
Author(s):  
Marco Troncossi ◽  
Sara Taddia ◽  
Alessandro Rivola ◽  
Alberto Martini
Keyword(s):  
Viscoelastic Material ◽  
Composite Laminates ◽  
Vehicle Body ◽  
Composite Panels ◽  
Damping Properties ◽  
Aerospace Applications ◽  
Body Shell ◽  
Promising Solution ◽  
Noise Vibration ◽  
Thin Panel

This work aims to identify the damping properties of a commercial viscoelastic material that can be embedded and cured between the layers of composite laminates. The material may be adopted for reducing the vibration response of composite panels, typically used in automotive and aerospace applications, e.g., as vehicle body shell components. In order to objectively estimate the actual potential to enhance the noise vibration and harshness aspects, the effects of the viscoelastic material on the modal parameters of carbon/epoxy thin panels are quantitatively assessed through experimental modal analysis. Two different experiments are conducted, namely impact hammer tests and shaker excitation measurements. Based on the results of the experimental campaign, the investigated material is confirmed as a promising solution for possibly reducing the severity of vibrations in composite panels, thanks to its high damping properties. Indeed, the presence of just one layer proves to triple the damping properties of a thin panel. An approximate damping model is derived from the measured data in order to effectively simulate the dynamic response of new design solutions, including thin composite panels featuring the viscoelastic material.

Combined Effects of Stress Concentration and Fatigue on the Reliability of Notched Laminates

2006 ◽  
Author(s):  
R. Ganesan ◽  
A. K. Arumugam
Keyword(s):  
Stress Concentration ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Fatigue Loading ◽  
Stochastic Approach ◽  
Strength Properties ◽  
Combined Effect ◽  
Practical Reasons ◽  
Aerospace Applications ◽  
Structural Applications

Composite laminates are used in structural applications such as aircraft wings and tail structures. Drilling holes and making cutouts in these laminates are unavoidable for practical reasons. As a result, stress concentration is introduced near the hole or cutout, and the load-bearing capacity of the structure is reduced. In addition, composite laminates used in aerospace applications are subjected to considerable fatigue loading due to service conditions. In composite laminates, fatigue causes reduction in stiffness and strength. The objective of the present work is to study the combined effect of stress concentration and fatigue on the composite laminate. Since composite laminate displays significant variation in material and strength properties, the stress distribution in the laminate is stochastic in nature. It is more appropriate to analyze the notched composite laminates using a stochastic approach and to design the laminate based on a reliability-based design approach. In the present work, such an approach is developed and the combined effect of stress concentration and fatigue on the reliability of the laminate is investigated.

scholarly journals Formability and interface structure of Al/Mg/Al composite sheet rolled by hard-plate rolling (HPR)

2021 ◽  
Author(s):  
Peng Da Huo ◽  
Feng Li ◽  
Ye Wang ◽  
Xing Mao Xiao
Keyword(s):  
Diffusion Layer ◽  
Composite Laminates ◽  
Composite Plate ◽  
Rolling Direction ◽  
Interface Structure ◽  
Composite Panels ◽  
Plate Rolling ◽  
Al Composite ◽  
Hot Rolled ◽  
Welding Pressure

Abstract How to improve the bonding ability and quality perform between heterogeneous plates has always been one of the difficult issues that have long been concerned in the field of high-performance heterogeneous composite plate forming and manufacturing. This paper proposes a new method for manufacturing heterogeneous composite panels—composite panels by hard-plate rolling (HPR). In addition to adding hard plates above and below the aluminum/magnesium/aluminum (Al/Mg/Al) composite slab, the research results of the hot rolling process of the composite plate with or without the hard plates at 40%, 60%, and 80% reduction show that the hard plates can be rolled During the manufacturing process, the shear stress in the rolling direction (RD) is partially converted into the compressive stress in the normal direction (ND), which then increases the welding pressure between the heterogeneous composite laminates, which can inhibit the occurrence of bending and edge cracks, and significantly improve the quality and shape of the board ability. At the same time, through the study of the interface structure of the composite plate, it can be known that metallurgical bonding can be achieved with a small reduction after the addition of the hard-plate, and two clear layers of Al3Mg2 and Al17Mg12 intermetallic compounds appear at the Al/Mg interface, and the thickness of the diffusion layer is uniform. Significantly larger than the traditional hot-rolled composite board, the thickness of the diffusion layer can reach 38µm under the condition of 60% reduction under the action of the hard-plate, the yield strength is 172.3MPa, and the elongation reaches 21.5%. In summary, the hot-rolled by hard-plate is high forming and manufacturing of performance heterogeneous composite panels provides a method.

Radiated Noise from Tire/Wheel Vibration

1997 ◽  
Vol 25 (1) ◽  
pp. 29-42 ◽  
Author(s):  
E-J. Ni ◽  
D. S. Snyder ◽  
G. F. Walton ◽  
N. E. Mallard ◽  
G. E. Barron ◽  
...  
Keyword(s):  
Sound Pressure ◽  
Sound Quality ◽  
Vehicle Body ◽  
Body Structure ◽  
Vehicle Interior ◽  
Noise Sources ◽  
Airborne Noise ◽  
Total Vehicle ◽  
Noise Vibration ◽  
Wheel Vibration

Abstract As a general trend, vehicle sound quality has significantly improved in recent years. This is primarily due to improved body structure and powertrain design. As demand for better vehicle sound quality increases, it is important to study all possible noise sources contributing to noise, vibration, and harshness (NVH). Tire vibration has long been recognized as a source of airborne noise. Some effects of wheel design on tire noise have also been well understood for sometime. But the dynamic interaction between tire and wheel designs and its effect on vehicle NVH, although frequently observed for many years, has only recently been identified in the 200–350 Hz frequency range. Different wheels can produce perceptible differences in vehicle interior sound pressure levels in a road test. Hence, the authors have developed a process to quantify and reduce noise caused by a vibrating tire/wheel assembly. This paper discusses the general flow of the process, which begins with the identification of NVH issues on a total vehicle level. Modeling and optimization of the aluminum wheel was chosen as the focus of this project for two reasons. First, the interior sound pressure level (SPL) around 285 Hz is about 5–7 dBA higher in a vehicle equipped with aluminum wheels rather than a steel design. Second, modifying the wheel is far more economical and faster due to its simplicity of design than the complexity of either the vehicle body structure or a tire.

scholarly journals Isogeometric analysis for simulation of progressive damage in composite laminates

2018 ◽  
Vol 52 (25) ◽  
pp. 3471-3489 ◽  
Author(s):  
Marco S. Pigazzini ◽  
Yuri Bazilevs ◽  
Andrew Ellison ◽  
Hyonny Kim
Keyword(s):  
Composite Laminates ◽  
Isogeometric Analysis ◽  
Composite Structures ◽  
Low Velocity Impact ◽  
Stiffened Panel ◽  
Progressive Damage ◽  
Low Velocity ◽  
New Class ◽  
Aerospace Applications ◽  
Post Impact

The increasing popularity of composite materials in aerospace applications is creating the need for a new class of predictive methods and tools for the simulation of progressive damage in laminated fiber-reinforced composite structures. The unique challenges associated with modeling damage in these structures may be addressed by means of thin-shell formulations which are naturally developed in the context of Isogeometric Analysis. In this paper, we further validate our recently developed Isogeometric Analysis-based multi-layer shell model for progressive damage simulations using experimental data for low-velocity impact on a 24-ply flat panel. The validation includes a careful comparison of delamination and matrix damage patterns predicted by the Isogeometric Analysis-based simulation and those obtained from post-impact non-destructive evaluation of the damaged coupon. The Isogeometric Analysis-based formulation is then deployed on two additional examples: a stiffened panel and a full-scale UAV wing, to demonstrate its suitability for, and ease of application to, typical aerospace composite structures.

Analytical studies and numerical predictions of stresses in shear joints of layered composite panels for aerospace applications

2021 ◽  
Vol 255 ◽  
pp. 112927
Author(s):  
C.K. Krishnadasan ◽  
N. Siva Shanmugam ◽  
B. Sivasubramonian ◽  
B. Nageswara Rao ◽  
R. Suresh
Keyword(s):  
Layered Composite ◽  
Composite Panels ◽  
Aerospace Applications ◽  
Numerical Predictions ◽  
Analytical Studies

Structural Damping Enhancement of Nanocomposites With Engineered Vapor Grown Carbon Nanofiber Paper

2006 ◽  
Author(s):  
Jihua Gou ◽  
Haichang Gu ◽  
Gangbing Song
Keyword(s):  
Carbon Nanotubes ◽  
Energy Dissipation ◽  
Carbon Nanofibers ◽  
Composite Laminates ◽  
Carbon Nanofiber ◽  
Glass Fibers ◽  
Hybrid Nanocomposites ◽  
Structural Vibration ◽  
Damping Properties ◽  
Structural Damping

Due to their nanometer size and low density, the surface area to mass ratio of carbon nanotubes and carbon nanofibers is extremely large. In addition, the large aspect ratio and high elastic modulus of carbon nanotubes and carbon nanofibers allow for large differences in strain between the constituents in the nanocomposites, which could enhance the interfacial energy dissipation ability. While there are many reported benefits of carbon nanotubes and carbon nanofibers in the nanocomposites, the potential of carbon nanotubes and carbon nanofibers to enhance the structural damping properties of nanocomposites has not been fully explored. This paper presents a novel process to manufacture multifunctional and cost-effective hybrid nanocomposites through integrating engineered carbon nanofiber paper into traditional fiber reinforced composites to improve the structural damping properties. The vacuum-assisted resin transfer molding (VARTM) process was employed to fabricate the nanocomposites by using engineered carbon nanofiber papers as inter-layers or surface layers of traditional composite laminates. To characterize the structural damping properties, the influence of frequency dependence was analyzed through the experiments conducted using the nanocomposite beams. It was found that there is up to 200–700% increase of the damping ratios at higher frequencies. It was found that the connectivities between carbon nanofibers and short glass fibers within the carbon nanofiber paper were responsible for the significant energy dissipation in the nanocomposites during structural vibration applications.

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