scholarly journals The Influence of Low Energy Impacts on the Static and Dynamic Response of a Foam Core Composite Wing

2009 ◽  
Vol 20 (11) ◽  
pp. 1351-1361 ◽  
Author(s):  
E. Aktaş ◽  
M. Seaver ◽  
J.M. Nichols ◽  
S.T. Trickey ◽  
W.R. Davis
Keyword(s):  
Dynamic Response ◽  
Low Energy ◽  
Foam Core ◽  
Composite Wing

Damage Characterization of Composite Wing Subjected to Impact Loading: An Experimental Study

2009 ◽  
Author(s):  
Cristobal Hiche ◽  
Clyde K. Coelho ◽  
Albert Moncada ◽  
Masoud Yekani Fard ◽  
Aditi Chattopadhyay
Keyword(s):  
High Energy ◽  
Chord Length ◽  
Low Energy ◽  
Fe Model ◽  
Foam Core ◽  
Damage Characterization ◽  
Fbg Sensors ◽  
The Impact ◽  
Composite Wing

Damage on woven composites is a phenomenon that is difficult to characterize due to complex weave geometry. A woven composite wing structure adds to the complexity of characterizing damage through Fiber Bragg Grating (FBG) sensors. The present paper studies the FBG response and damage characterization of foam core and hollow composite wings. Plain and twill weave wings were manufactured and subjected to low energy (52.5J) and high energy (150J) impacts. Damage was assessed using FBG sensors, flash thermography, and visual inspection of the wings. Two FBG sensors were placed along the chord length and the spanwise direction at equal distances from the impact site to measure the axial strain as a function of time. The main failure modes of foam core wings were fiber breakage and foam crushing for high energy impacts, while core crushing and delamination between the core and the composite wing was found for low energy impacts. The hollow wings had a significant reduction in stiffness, resulting in a ripple effect where the wing would go into tension, then compression. This phenomenon varied depending on the location of the sensors on the wing. Although the impact zone was near the middle of the chord length of the wing, the resulting stress has caused large damage at the leading edge and significant debonding at the trailing edge of the hollow wing. An FE model was created to validate the experimental results and showed good correlation between the high stress areas in the model, the FBG response, and the damage sites on the wing.

Dynamic Response and Damage Mechanism of Two-Core Composite Sandwich Panels under Low-Velocity Impact

2013 ◽  
Vol 405-408 ◽  
pp. 2810-2814
Author(s):  
Chang Liang Li ◽  
Da Zhi Jiang ◽  
Jing Cheng Zeng ◽  
Su Li Xing
Keyword(s):  
Dynamic Response ◽  
Contact Force ◽  
Impact Energy ◽  
Sandwich Structures ◽  
Sandwich Panels ◽  
Damage Mechanism ◽  
The Other ◽  
Foam Core ◽  
Transverse Impact ◽  
Low Velocity

Dynamic response and damage mechanism of two-core sandwich panels with foam and honeycomb cores and glass fiber/epoxy composite sheets under low-velocity transverse impact are investigated. The emphasis is focused on the contact force response and crash mechanism of the two-core sandwich panels. Effects of configurations, impact energy levels and types of the cores on the dynamic response are investigated. A modified drop-test experiment is carried out to obtain contact force history of the two-core sandwich structures under different impact energies. The experimental results show that the 10:10 configurations for both honeycomb and foam core sandwich structures under lower impact energy absorb more impact energy than the other two structures. However, under higher impact energy, the honeycomb core sandwich structures of 15:5 configuration absorbs a little more impact energy than the other two, while for the foam core sandwich structures the 5:15 configuration shows a little better impact resistance. Results also show that when impact energy is low foam core sandwich structures do better in absorbing impact energy than the honeycomb ones.

Research on the Anti-Penetration Performance of Aluminum Foam Sandwich Plate

2014 ◽  
Vol 624 ◽  
pp. 20-24 ◽  
Author(s):  
Gui Yun Hang ◽  
Wen Li Yu ◽  
Tao Wang ◽  
Jin Tao Wang ◽  
Zhen Li
Keyword(s):  
Numerical Simulation ◽  
Finite Elements ◽  
Dynamic Response ◽  
Direct Effect ◽  
Aluminum Foam ◽  
Sandwich Plate ◽  
Sandwich Structures ◽  
Simulation Method ◽  
Foam Core ◽  
Penetration Process

This paper investigated the anti-penetration performance of different sandwich structures plate using numerical simulation method. Finite elements models of the bullet and sandwich plate were established. The penetration performance of sandwich plate by bullet was simulated by software of LS-DYNA and dynamic response of the bullet during the penetration process was got. The results show that the anti-penetration performance is different because of the different cores in the plate. Besides, the density of the aluminum foam core has a direct effect on the performance. This paper could provide some reference for the designing of sandwich structures.

Quantitative Detection of Low Energy Impact Damage in a Sandwich Composite UAV Wing

2008 ◽  
Author(s):  
Engin Aktas ◽  
Mark Seaver ◽  
Jonathan M. Nichols ◽  
Stephen T. Trickey
Keyword(s):  
Impact Damage ◽  
Vibrational Excitation ◽  
Gaussian White Noise ◽  
Low Energy ◽  
Sandwich Composite ◽  
Quantitative Detection ◽  
Foam Core ◽  
Vibrational Response ◽  
Energy Impact ◽  
Deposited Energy

This work describes damage detection efforts applied to a foam core composite wing following a series of low energy impacts in adjacent locations. The wing is a sandwich composite, composed of 4 layers of woven carbon fiber fabric surrounding a short aluminum core in the center (where it’s connected to the fuselage) and a foam core for the outer portions of the wing. The wing measures 1320 mm. × 152.4 mm. × 13.4 mm and has an airfoil cross-section. Thirteen impacts (6 – 8 J deposited energy) were applied at adjacent locations approximately 1/3 of the way out from the center. Following one or two impacts, the wing was tested using static tip deflection and dynamic vibrational excitation. Static and dynamic strains were measured using 8 fiber Bragg grating (FBG) sensors. Dynamic acceleration was also monitored using 3 conventional accelerometers. Dynamic excitation included the output of a Lorenz oscillator (0 – ∼150 Hz), simulated gust loading (0 – 150 Hz), and Gaussian white noise (0 – 1500 Hz). The analysis is a quantitative assessment of response nonlinearity based on the assumption that the undamaged wing behaves linearly and that the damage introduces nonlinearity into the vibrational response.

scholarly journals Steady State and Dynamic Response of Voltage-Operated Membrane Gates

Membranes ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 34
Author(s):  
David Nicolas Østedgaard-Munck ◽  
Jacopo Catalano ◽  
Anders Bentien
Keyword(s):  
Steady State ◽  
Dynamic Response ◽  
Flow Cell ◽  
Low Energy ◽  
Energy Requirements ◽  
Carbon Paper ◽  
Pump Operation ◽  
Precise Control ◽  
Voltage Gated ◽  
Electrochemical Flow Cell

An electrochemical flow cell with Nafion 212, aqueous LiI/I 2 redox solution, and carbon paper electrode was operated as an electro-osmotic gate based on the Electrokinetic Energy Conversion (EKEC) principle. The gate was operated in different modes. (i) In normal DC pump operation it is shown to follow the predictions from the phenomenological transport equations. (ii) Furthermore, it was also demonstrated to operate as a normally open, voltage-gated valve for microfluidic purposes. For both pump and valve operations low energy requirements (mW range) were estimated for precise control of small flows ( μ L range). (iii) Finally, the dynamic response of the pump was investigated by using alternating currents at a range of different frequencies.

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