Case Study and Structure

Katunin, A., Dragan, K., & Dziendzikowski, M. (2015). Damage identification in aircraft composite structures a case study using various non-destructive testing techniques. Composite Structures, 127, 1-9.

The research article shows that the application of composite structure has become increasing popular in the aerospace industry based on their unique properties, which include excellent weight ratio, strength, and corrosion resistance. To ascertain a safety of composite elements and structural integrity on aircraft, it is critical to test the structural integrity. Thus, the authors test three composite structures developed from plastic, glass fiber reinforced, and hybrid composite along with the core manufactured using the same aluminum fact sheets and materials. The authors perform the test using various techniques that include ultrasonic, PZT sensing, vibration -based in section and thermography to analyze the application of the methods on aircraft elements. The results of the analysis reveal that pulsed thermography and ultrasonic scanning have allowed the effectiveness in localization and detection of introduced impact damage. However, the ultrasonic scanning reveals the detailed damage evaluation than the thermographic technique.

Ampatzidis, T., & Chronopoulos, D. (2016). Acoustic transmission properties of pressurized and pre-stressed composite structures. Composite Structures, 152, 900-912.

The authors examine the effect of the pre-stress that includes pressure and tension on acoustic behavior and wave propagation of laminate. Ampatzidis, et l. (2016) use the two-dimensional WFEM layer to calculate the STL (sound transmission loss) of the thick structure when accounting the antisymmetric and symmetric wave motion. The authors also predict the dispersion characteristics of two sandwiched structured and dimensional layered using the "WFEM (Wave Finite Element Method)" (Ampatzidis, & Chronopoulos, 2016 p 152). Ampatzidis, et l. (2016) also examine the pre-stressed and non-stressed scenarios, and are able to form a polynomial eigenvalue problem after extracting the stiffness matrix and mass of a small periodic segment of the composite structure "using commercially available Finite Elements software." (Ampatzidis, & Chronopoulos, 2016 p 152). The article also investigates the monolithic in both compression and tension while examining the sandwiched in laminate internal core pressure along with the compression and tension aspect. Moreover, the article calculates the important of SEA quantities and loss factor using the modal density. The results reveal that pre-stress affects the wave dispersion curves and loss factor leading to an alteration of radiation efficiency, modal density, and TL behavior.

Garnier, C., Pastor, M., Lorrain, B., & Pantale, O. (2013). Fatigue behavior of impacted composite structures. Composite Structures, 100, 443-450.

In this study, it is revealed that an impact of damage is critical when a structural engineer decides to design the composite structure. The composites are different from metallic materials because they can sustain the impact with recording visible traces on the surface. However, the dynamic stress may still modify the structure of the internal cohesion.

The focus of this study is to compare the mechanical behaviors of "different impact-damaged composite Materials." (Garnier, Pastor, Lorrain, & Pantale, 2013 p 443). After using the LRI (Liquid Resin Infusion process), the authors realize three composite materials based on three different polymerization cycles. Garnier et al. (2013) also develop two experimental methods to ascertain the impact methods and conditions were respected. The outcome of the two experiments determines the best polymerization cycle and fatigue tests showing their compliance with fatigue testing standards.

Thoppul, S. D., Finegan, J., & Gibson, R. F. (2009). Mechanics of mechanically fastened joints in polymer -- matrix composite structures -- A review. Composites Science and Technology, 69, 301-329.

The aim of this study is to evaluate the use of experimental data combined with semi-empirical procedures to predict the strength of joints and basic laminate properties function. With an increase in the use of advanced composite structural materials, there is a need to enhance a greater understanding of the mechanical behaviors and mechanically fastened joints. The authors present a comprehensive review of the literature to enhance a greater understanding of "mechanics of mechanically fastened joints in polymer -- matrix composite structures." Thoppul, Finegan, & Gibson, 2009 p 301). The authors also examine relevant mechanical test standards and method. The review is followed by a discussion of joint design methodology, mechanical design, the influence of fastener preload selection and geometric effect. The article also examines the bearing failure along with the failure prediction both in dynamically and statically loaded joints. Finally, the study evaluates the effect of moisture and temperature on failure and strength.