Blast Hazard Impact on V-Shape Composite Panel Performance

AbstractThe article is in line with the contemporary interests of companies from the aviation industry. It describes thermoplastic material and inspection techniques used in leading aviation companies. The subject matter of non-destructive testing currently used in aircraft inspections of composite structures is approximated and each of the methods used is briefly described. The characteristics of carbon preimpregnates in thermoplastic matrix are also presented, as well as types of thermoplastic materials and examples of their application in surface ship construction. The advantages, disadvantages and limitations for these materials are listed. The focus was put on the explanation of the ultrasonic method, which is the most commonly used method during the inspection of composite structures at the production and exploitation stage. Describing the ultrasonic method, the focus was put on echo pulse technique and the use of modern Phased Array heads. Incompatibilities most frequently occurring and detected in composite materials with thermosetting and thermoplastic matrix were listed and described. A thermoplastic flat composite panel made of carbon pre-impregnate in a high-temperature matrix (over 300°C), which was the subject of the study, was described. The results of non-destructive testing (ultrasonic method) of thermoplastic panel were presented and conclusions were drawn.

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Acoustic Panels Made of Paper Sludge and Clay Composites

Sustainability ◽

10.3390/su13020637 ◽

2021 ◽

Vol 13 (2) ◽

pp. 637

Author(s):

Tomas Astrauskas ◽

Tomas Januševičius ◽

Raimondas Grubliauskas

Keyword(s):

Absorption Coefficient ◽

Sound Absorption ◽

Composite Panel ◽

Sound Absorption Coefficient ◽

Core Material ◽

Paper Sludge ◽

Frequency Range ◽

Absorption Properties ◽

Air Gaps ◽

The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

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Modal vibration response of hybrid composite panel having artificial impregnated defects: A comparison

10.1063/5.0049947 ◽

2021 ◽

Author(s):

Rahul Kumar Patil

Keyword(s):

Hybrid Composite ◽

Vibration Response ◽

Composite Panel ◽

Modal Vibration

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Three-layer composite panel with discrete layer and bionic principles

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1083/1/012027 ◽

2021 ◽

Vol 1083 (1) ◽

pp. 012027

Author(s):

I A Mayatskaya ◽

B M Yazyev ◽

V D Eremin

Keyword(s):

Composite Panel ◽

Layer Composite ◽

Discrete Layer

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Probability-based diagnostic imaging with corrected weight distribution for damage detection of stiffened composite panel

Structural Health Monitoring ◽

10.1177/14759217211033967 ◽

2021 ◽

pp. 147592172110339

Author(s):

Guoqiang Liu ◽

Binwen Wang ◽

Li Wang ◽

Yu Yang ◽

Xiaguang Wang

Keyword(s):

Distribution Function ◽

Diagnostic Imaging ◽

Weight Distribution ◽

Composite Structures ◽

Damage Identification ◽

Guided Wave ◽

Composite Panel ◽

Damage Localization ◽

Localization Accuracy ◽

Direct Interpretation

Due to no requirement for direct interpretation of the guided wave signal, probability-based diagnostic imaging (PDI) algorithm is especially suitable for damage identification of complex composite structures. However, the weight distribution function of PDI algorithm is relatively inaccurate. It can reduce the damage localization accuracy. In order to improve the damage localization accuracy, an improved PDI algorithm is proposed. In the proposed algorithm, the weight distribution function is corrected by the acquired relative distances from defects to all actuator–sensor pairs and the reduction of the weight distribution areas. The validity of the proposed algorithm is assessed by identifying damages at different locations on a stiffened composite panel. The results show that the proposed algorithm can identify damage of a stiffened composite panel accurately.

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Full-Field Operational Modal Analysis of an Aircraft Composite Panel from the Dynamic Response in Multi-Impact Test

Sensors ◽

10.3390/s21051602 ◽

2021 ◽

Vol 21 (5) ◽

pp. 1602

Author(s):

Ángel Molina-Viedma ◽

Elías López-Alba ◽

Luis Felipe-Sesé ◽

Francisco Díaz

Keyword(s):

Modal Analysis ◽

Energy Absorption ◽

High Speed ◽

Operational Modal Analysis ◽

Modal Identification ◽

Image Correlation ◽

Composite Panel ◽

Impact Excitation ◽

Full Field ◽

The Impact

Experimental characterization and validation of skin components in aircraft entails multiple evaluations (structural, aerodynamic, acoustic, etc.) and expensive campaigns. They require different rigs and equipment to perform the necessary tests. Two of the main dynamic characterizations include the energy absorption under impact forcing and the identification of modal parameters through the vibration response under any broadband excitation, which also includes impacts. This work exploits the response of a stiffened aircraft composite panel submitted to a multi-impact excitation, which is intended for impact and energy absorption analysis. Based on the high stiffness of composite materials, the study worked under the assumption that the global response to the multi-impact excitation is linear with small strains, neglecting the nonlinear behavior produced by local damage generation. Then, modal identification could be performed. The vibration after the impact was measured by high-speed 3D digital image correlation and employed for full-field operational modal analysis. Multiple modes were characterized in a wide spectrum, exploiting the advantages of the full-field noninvasive techniques. These results described a consistent modal behavior of the panel along with good indicators of mode separation given by the auto modal assurance criterion (Auto-MAC). Hence, it illustrates the possibility of performing these dynamic characterizations in a single test, offering additional information while reducing time and investment during the validation of these structures.

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Development of lignocellulosic fiber reinforced cement composite panels using semi-dry technology

Cellulose ◽

10.1007/s10570-021-03755-4 ◽

2021 ◽

Vol 28 (6) ◽

pp. 3631-3645

Author(s):

K. M. Faridul Hasan ◽

Péter György Horváth ◽

Tibor Alpár

Keyword(s):

Flexural Modulus ◽

Cement Composite ◽

Composite Panel ◽

Bending Test ◽

Morphological Properties ◽

Cement Stone ◽

Composite Panels ◽

Internal Bonding ◽

Dry Process ◽

Lignocellulosic Fiber

AbstractThere is a growing interest in developing cement bonded lignocellulosic fiber (LF) composites with enhanced mechanical performances. This study assessed the possibility of developing composite panels with 12 mm thickness and around 1200 kg/m3 nominal densities from ordinary Portland cements (OPC) and mixed LFs from seven different woody plants found in Hungary. Once the mixed LFs were sieved and found fine (0–0.6 mm) and medium (0.6–0.8 mm) length fibers. The optimum ratio for LF, OPC, water glass (Na2SiO3), and cement stone was found to be 1:3.5:0.7:0.07. The semi-dry process, which is a comparatively cheaper and less labor intensive technology, was used for producing the composites. After 28 days of curing, the composite panels were characterized for mechanical, physical, thermal, and morphological properties. A scanning electron microscopy (SEM) test was conducted to observe the fiber orientation in the matrix before and after the bending test, which showed the clear presence of the fibers in the composites. The FTIR (Fourier transform infrared spectroscopy) was conducted to investigate the presence of chemical compounds of LF in the composite panels. Different physical (water absorption and thickness swelling) characteristics of the composite panels were investigated. Furthermore, mechanical properties (flexural properties and internal bonding strength) of the composite panels were also found to be satisfactory. The flexural modulus and internal bonding strengths of composite panel 2 is higher than other three boards, although the flexural strength is a little lower than composite panel 1. The thermogravimetric analysis and differential thermogravimetry also indicated better thermal stability of composite panels which could be used as potential insulation panel for buildings. Graphic abstract

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Characterization and ballistic performance of thin pre-damaged resin-starved aramid-fiber composite panels

Textile Research Journal ◽

10.1177/00405175211013424 ◽

2021 ◽

pp. 004051752110134

Author(s):

Cerise A Edwards ◽

Stephen L Ogin ◽

David A Jesson ◽

Matthew Oldfield ◽

Rebecca L Livesey ◽

...

Keyword(s):

Fiber Composite ◽

Plane Deformation ◽

Ballistic Impact ◽

Image Correlation ◽

Composite Panel ◽

Composite Panels ◽

Micro Computed Tomography ◽

Ballistic Performance ◽

Low Level ◽

Out Of Plane

Military personnel use protective armor systems that are frequently exposed to low-level damage, such as non-ballistic impact, wear-and-tear from everyday use, and damage during storage of equipment. The extent to which such low-level pre-damage could affect the performance of an armor system is unknown. In this work, low-level pre-damage has been introduced into a Kevlar/phenolic resin-starved composite panel using tensile loading. The tensile stress–strain behavior of this eight-layer material has been investigated and has been found to have two distinct regions; these have been understood in terms of the microstructure and damage within the composite panels investigated using micro-computed tomography and digital image correlation. Ballistic testing carried out on pristine (control) and pre-damaged panels did not indicate any difference in the V50 ballistic performance. However, an indication of a difference in response to ballistic impact was observed; the area of maximal local out-of-plane deformation for the pre-damaged panels was found to be twice that of the control panels, and the global out-of-plane deformation across the panel was also larger.

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