Effects of Absorbed Moisture Content on the Impact Response of Specially-Orthotropic Composite Plates

Author(s):  
Furqan Ahmad ◽  
Fethi Abbassi ◽  
Sajjad Miran

Abstract This paper addresses the hygroscopic effects on the impact response of specially-orthotropic carbon fiber reinforced polymer composite plates under low-velocity impact loading. The material used in this study is Toray T800/3900 which is consist of carbon fibers and epoxy resin. For different percentage of moisture content by weight in the composite plates, low-velocity impact tests were done by using the 8-ply unidirectional [UD] and cross-ply [CP] composite plates with newly designed mini-drop tower testing machine. To study the hygroscopic effects, specimens were impacted by constant weight of impactor (3.44 Kg) with fixed impact height of 0.70 m corresponding to 23.62 J impact energy. The experiments were carried out on plates with dimension of 125 mm × 125 mm × 1.5 mm for simply supported boundary conditions. All UD composite plates were broken into two parts, but the impactor bounces back after hitting the top layer of the CP composite plate for all conditions. The strength of the UD composite plates decreased with increase of moisture contents, but with the increased of moisture contents, a small change was observed in the peak force, time to peak force values and absorbed energy for the CP composite plates. The large size damage areas were observed for wet plates as compared to dry plates. Absorbed moisture contents also have effect on the impactor velocity and impactor displacement.

2021 ◽  
pp. 152808372110154
Author(s):  
Ziyu Zhao ◽  
Tianming Liu ◽  
Pibo Ma

In this paper, biaxial warp-knitted fabrics were produced with different high tenacity polyester linear density and inserted yarns density. The low-velocity impact property of flexible composites made of polyurethane as matrix and biaxial warp-knitted fabric as reinforcement has been investigated. The effect of impactor shape and initial impact energy on the impact response of flexible composite is tested. The results show that the initial impact energy have minor effect on the impact response of the biaxial warp-knitted flexible composites. The impact resistance of flexible composite specimen increases with the increase of high tenacity polyester linear density and inserted yarns density. The damage morphology of flexible composite materials is completely different under different impactor shapes. The findings have theoretical and practical significance for the applications of biaxial warp-knitted flexible composite.


2014 ◽  
Vol 629 ◽  
pp. 503-506 ◽  
Author(s):  
Al Emran Ismail ◽  
M.A. Hassan

This paper presents the experimental investigations on the low velocity impact response of woven kenaf fiber reinforced composites. Kenaf yarns are weaved with an orientation of 00 of warp and 900 of weft to form woven kenaf mat. Three woven kenaf mats are stacked together to achieve the specified sequences. The woven stacked kenaf mats are hardened with polymeric resin and compressed to squeeze off any excessive resin and to minimize voids content. The hardened composite plates are perforated using different impact velocities. Impact responses of the composite plates are examined according to stacking sequences, impact velocities and fragmentation patterns. According to the present results, the impact strength is strongly related with the impact velocity. If higher impact velocity is used, the performances of load bearing are reduced. It is obvious that no significant features of composite fragmentations occurred from the perforated holes. However, relatively larger area of mechanical damages is found distributed around the holes, indicating the capability of composites to absorb energy effectively.


Author(s):  
Mohammad Noroozi ◽  
Majid Ghadiri ◽  
Asghar Zajkani

In the present paper, low velocity impact response of a size-dependent nanobeam in a thermal field with uniform temperature distribution has been investigated. The van-der Waals interaction force based on description of Lennard–Jonses is considered as the impact force between nanoparticle and nanobeam. According to third-order shear deformation beam theory, the governing equations are obtained using Hamilton's principle based on nonlocal strain-gradient theory. The Galerkin's method was adopted to solve the differential equations of nanobeam with simply supported and clamped boundary conditions. Afterward, the system of time-dependent equations by applying the fourth-order Runge–Kutta method is solved. The parametric study is presented to examine the effect of particle radius, initial velocity, temperature environment, the nonlocal parameter, and the length-scale parameter on the impact response of nanobeam.


2000 ◽  
Author(s):  
M. Motuku ◽  
R. M. Rodgers ◽  
S. Jeelani ◽  
U. K. Vaidya

Abstract The effect of foam core density and facesheet thickness on the low velocity impact response and damage evolution in homogeneous foam core sandwich composites was studied. The failure characteristics, initiation and evolution of damage as well as the effect of impact energy were investigated. A Dynatup 8210 Impact Test Machine was utilized to conduct the low-velocity impact tests. Characterization of the impact response was performed by comparing the impact load histories, impact plots and failure characteristics. Fractography analysis was conducted through the use of scanning electron microscopy (SEM) and optical microscopy. Three types of foam cores with different densities, namely Airlite B12.5, Rohacell IG-71R63 and Airex R63.5 foam cores, were used to study the effect of core density. Considering four groups of facesheets made of different layers of cross-ply carbon prepregs performed the effect of facesheet thickness. For all the facesheet thicknesses (0.011-0.894-cm thick) and impact energy (11-40 J) range considered in this study, the maximum load (Pm), deflection-at-maximum load (δm) and time-to-maximum load (tm) exhibited strong influence or dependence on the type of foam core as opposed to the facesheet thickness. The energy-to-maximum load (Em), total energy absorbed (Et) and total energy-to-impact energy (Et/Eimp) ratio became less sensitive on the foam core density (or type) with increasing facesheet thickness. A transition point from foam core to facesheet controlled impact behavior as a function of impact energy level was observed. The impact parameters varied either linearly or parabolically with impact energy depending on the impact energy level, type of foam core and facesheet thickness. Excellent repeatability of impact data was generally obtained with increase in foam core density.


2012 ◽  
Vol 33 (5) ◽  
pp. 655-664 ◽  
Author(s):  
Silvio Pappadà ◽  
Rocco Rametta ◽  
Alessandro Largo ◽  
Alfonso Maffezzoli

2000 ◽  
Vol 6 (3) ◽  
pp. 429-447 ◽  
Author(s):  
Ahmet S. Yigit ◽  
Andreas P. Christoforou

Materials ◽  
2005 ◽  
Author(s):  
S. Bernhardt ◽  
M. Ramulu ◽  
A. S. Kobayashi

The low-velocity impact response of a hybrid titanium composite laminate (HTCL), known as TiGr, was compared to that of graphite/epoxy composite. The TiGr material comprised of two outer plies of titanium foil surrounding a composite core. The composite core was PIXA-M (a high temperature thermoplastic) reinforced by IM-6 graphite fibers and consolidated by an induction heating process. The impact response of TiGr was characterized by two modes of failure which differed by failure or non-failure in tension of the bottom titanium ply. The ductility of titanium caused buckling by yielding whereas the brittle adjacent composite ply lead to fracture. The maximum failure force of the material correlated well with the previously reported static flexural data, and the material outperformed the commonly used graphite/epoxy.


2010 ◽  
Vol 168-170 ◽  
pp. 1149-1152
Author(s):  
Xiao Xiong Zha ◽  
Hong Xin Wang

The low velocity impact response of sandwich panels at different energy levels has been investigated by conducting drop-weight impact tests using an instrumented falling-weight impact tower. Impact parameters like maximum impact force and the extent of the damage were evaluated and compared for different types of sandwich panels. Finite elements simulations have been undertaken using the LS-DYNA software; the results of FE simulations have a good agreement with the experiments. It shows that, the impact force increased with thickness of face-sheets and foam core, the extent of the damage increased with the impact energy, sandwich panels with steel face sheet has a good impact resistance in comparison with sandwich panel with aluminum face sheets.


2016 ◽  
Vol 852 ◽  
pp. 23-28
Author(s):  
S. Subha ◽  
Battu Sai Krishna ◽  
Dalbir Singh ◽  
R. Gokulnath

In this study, an attempt has made to explore the low-velocity impact response of a Carbon/epoxy laminate (CFRP) and E-Glass/epoxy laminates (GFRP). The composite was reinforced with Graphene Nanoplatelets (GnPs) and impact energy absorption capacity was studied. The plain GFRP and plain CFRP were served as a baseline for comparison. These composite laminate plates were fabricated using hand layup technique. The tests were carried out on the laminate plate as per ASTM D5628 FD. Impact tests were performed using a specially designed vertical drop-weight testing machine with an impactor mass of 1.926 kg. The result shows that laminate plate reinforced with GnPs reinforcement enhances the impact energy absorption capacity of the composites almost 4.5 % in the case Carbon/epoxy laminate and 3.5 % in the case of and E-glass/epoxy laminate. The enhanced impact resistance could be attributed to increased interlaminar fracture toughness of the fibres.


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