Numerical/experimental evaluation of buckling behaviour and residual tensile strength of composite aerospace structures after low velocity impact

2016 ◽  
Vol 54 ◽  
pp. 1-9 ◽  
Author(s):  
E. Cestino ◽  
G. Romeo ◽  
P. Piana ◽  
F. Danzi
Keyword(s):  
Tensile Strength ◽  
Experimental Evaluation ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Aerospace Structures ◽  
Velocity Impact

The Study of Low-Velocity Impact Characteristics and Residual Tensile Strength of Carbon Fiber Composite Lattice Core Sandwich Structures

2011 ◽  
Vol 194-196 ◽  
pp. 117-120 ◽  
Author(s):  
Xai Mei Lu ◽  
Yun Fei Ma ◽  
Shi Xun Wang
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Sandwich Structures ◽  
Fiber Composite ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Carbon Fiber Composite ◽  
Velocity Impact ◽  
Composite Lattice ◽  
Lattice Core

In this paper, low-velocity impact characteristics and residual tensile strength of carbon fiber composite lattice core sandwich structures are investigated experimentally and numerically. Low-velocity impact tests and residual tensile strength tests are simulated by the FE (finite element) software, ABAQUS/Explicit and its subroutine (VUMAT). In order to give more detailed description about the impact damage of the structure and improve modeling accuracy, multi-steps analysis method is employed to simulate impact process and residual tensile strength test in one analysis model. The calculation results computed by the FE model have been compared to the value of experiments, the difference of impact process simulation is about 3.3% and that of tensile strength test simulation is about 12.9%. The calculation error of computation model is acceptable, since unavoidable damage could be introduced in the courses of manufacture, processing and transportation of composite materials, and these damages are determinated difficultly in the computation programs. Next, the degradation tendency chart of residual tensile strength and impact energy threshold Uo of carbon fiber composite lattice core sandwich structures are obtained by the computation value of residual tensile strength after impacted with different impact energy. Previously, this threshold can only be obtained by experiment tests. After the contact force which is bigger than the threshold Uo impact on the sandwich structures, the residual tensile strength of structures are degraded greatly. This conclusion is significant for the design and application of carbon fiber composite lattice core sandwich structures.

Investigation of nano-hybridization effects on low velocity impact behaviors of basalt fiber reinforced composites

2020 ◽  
pp. 002199832094964
Author(s):  
İbrahim Demirci ◽  
Ahmet Avcı ◽  
Mehmet Turan Demirci
Keyword(s):  
Tensile Strength ◽  
Epoxy Composites ◽  
Low Velocity Impact ◽  
Maximum Force ◽  
Fracture Mechanisms ◽  
Fiber Reinforced ◽  
Epoxy Nanocomposites ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

In general the nanoparticles increase the mechanical and impact behaviors of fiber reinforced polymer based composites. However, the effects of the hybridization of nanoparticles and their reasons over the nano scale fracture mechanisms have not been adequately studied for fiber reinforced composites. In this study, the low velocity impact responses and the mechanical behaviors were investigated for 4%wt. SiO2 nanoparticles filled BFR/Epoxy nanocomposites, 0.5%wt. MWCNTs filled BFR/Epoxy nanocomposites, 4%wt. SiO2 nanoparticles and 0.5%wt. MWCNTs nano-hybrid filled BFR/Epoxy nanocomposites and unfilled BFR/Epoxy composites. The tensile and low velocity impact tests at 10 J and 20 J of energy levels were applied to nanoparticles, nano-hybrid and unfilled BFR/Epoxy composites in order to define the effects of nanoparticles and nano-hybrid particles on the impact and mechanical features according to in accordance with ASTM D3039/D3039M-14 and ASTM D7136/7136M standards. It was observed that SiO2 nanoparticles addition to BFR/Epoxy for both 10 J and 20 J showed the highest tensile strength, maximum force, rebound energy and the lowest displacements and absorbed energy. SiO2+MWCNTs nano-hybrid addition to BFR/Epoxy improved higher low velocity impact responses and tensile strength than MWCNTs addition. The specimens of unfilled BFR/Epoxy composites showed the lowest tensile strength and maximum force and the highest maximum force, displacements and absorbed energy. Microscope and SEM analyses demonstrated that minimum failures like fiber breakages, delamination and debonding were observed by filling SiO2 nanoparticles provided the nano scale fracture mechanisms. In addition MWCNTs hybridization with SiO2 nanoparticles minimizes negative effects of MWCNTs micro size length and improved the impact and mechanical behaviors.

Mechanical and low-velocity impact properties of epoxy-composite beams reinforced by MWCNTs

2018 ◽  
Vol 53 (5) ◽  
pp. 693-705 ◽  
Author(s):  
Mehdi Ranjbar ◽  
Saeed Feli
Keyword(s):  
Tensile Strength ◽  
Young’S Modulus ◽  
Contact Force ◽  
Young's Modulus ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Impact Properties ◽  
Velocity Impact ◽  
Pure Epoxy ◽  
The Impact

The effect of different weight percentages (wt.%) of MWCNTs includes 0, 0.17, 0.34 and 0.51% on the mechanical and low-velocity impact properties are presented on the example of the pure epoxy and epoxy/fiberglass composites beams. A sonication technique is used to disperse MWCNTs in the epoxy network and the nanocomposite beams are fabricated using hand lay-up technique. In tensile tests, the value of Young’s modulus, tensile strength and strain at break are reported. In the low-velocity impact tests on the MWCNTs/fiberglass/epoxy, the time-history response of contact force, displacement and velocity of the impactor and indentation and displacement of the beam are measured and presented. The results show that compared to pure epoxy, Young’s modulus and tensile strength of epoxy/MWCNTs are increased 21.98% and 58.32% at 0.34 wt.% of CNTs, respectively, and raised 1.05 and 1.17 times at 0.17 wt.% of CNTs for the epoxy/fiberglass/MWCNTs, respectively. It is observed that the excellent improvement in the impact properties is achieved for 0.34 wt.% of CNTs. A series of polynomial formulations as a function of wt.% of CNTs are proposed to calculate the Young’s modulus, peak contact force and maximum beam deflection at the impact position.

Sign in / Sign up

Export Citation Format

Share Document