Use of Statical Indentation Laws in the Impact Analysis of Laminated Composite Plates

1985 ◽  
Vol 52 (1) ◽  
pp. 6-12 ◽  
Author(s):  
T. M. Tan ◽  
C. T. Sun
Keyword(s):  
Impact Analysis ◽  
Laminated Composite ◽  
Composite Plates ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
The Impact ◽  
Theoretical Results ◽  
Theoretical Procedure ◽  
Good Agreement

The low-velocity impact response of graphite/epoxy laminates was investigated theoretically and experimentally. A nine-node isoparametric plate finite element in conjunction with an empirical contact law was used for the theoretical investigation. Theoretical results are in good agreement with strain-gage experimental data. The results of the investigation indicate that the present theoretical procedure describes the impact response of laminate for low-impact velocities.

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

2019 ◽  
Author(s):  
Furqan Ahmad ◽  
Fethi Abbassi ◽  
Sajjad Miran
Keyword(s):  
Moisture Content ◽  
Composite Plates ◽  
Peak Force ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Constant Weight ◽  
Velocity Impact ◽  
Moisture Contents ◽  
The Impact

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.

scholarly journals On the Low Velocity Impact Response of Laminated Composite Plates using the P-Version Ritz Method

2003 ◽  
Vol 12 (5) ◽  
pp. 096369350301200 ◽  
Author(s):  
Y.P. Markopoulos ◽  
V. Kostopoulos
Keyword(s):  
Dynamic Response ◽  
Laminated Composite ◽  
Composite Plates ◽  
Low Velocity Impact ◽  
Loading Path ◽  
Contact Boundary ◽  
Laminated Composite Plates ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

Low energy impact in composite laminates is often a crucial and destructive loading condition since it leads to significant internal damage, undetectable by visual inspection. Low velocity impact upon a laminated plate imposes a complex stress state mainly due to the structural heterogeneity resulting by the ply orientation of the constituent laminae and the contact boundary conditions, which lead to a loading path that varies with the impact energy and the properties of the impactor-impacted plate system. The present work deals with the development of a numerical scheme for the calculation of the dynamic response of any type of laminated composite plates under low-velocity impact. The governing non-linear, second order differential equations are derived using p-Ritz admissible polynomial functions and the elastoplastic version of the Hertzian contact law. The dynamic response of fully clamped, cross ply and angle ply composite plates are investigated.

Effect of long-term moisture exposure on impact response of glass-reinforced vinylester

2021 ◽  
pp. 147509022199616
Author(s):  
Fatemeh Alizadeh ◽  
Navid Kharghani ◽  
Carlos Guedes Soares
Keyword(s):  
Water Uptake ◽  
Failure Modes ◽  
Sea Water ◽  
Composite Plates ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Water Type ◽  
Interfacial Damage ◽  
Impact Properties ◽  
The Impact

Glass/Vinylester composite laminates are comprehensively characterised to assess its impact response behaviour under moisture exposure in marine structures. An instrumented drop weight impact machine is utilised to determine the impact responses of dry and immersed specimens in normal, salted and sea water. The specimens, which had three different thicknesses, were subjected to water exposure for a very long period of over 20 months before tested in a low-velocity impact experiment. Water uptake was measured primarily to study the degradation profiles of GRP laminates after being permeated by water. Matrix dissolution and interfacial damage observed on the laminates after prolonged moisture exposure while the absorption behaviour was found typically non-Fickian. The weight of the composite plates firstly increased because of water diffusion up to month 15 and then decreased due to matrix degradation. The specimens with 3, 6 and 9 mm thickness exhibited maximum water absorption corresponding to 2.6%, 0.7% and 0.5% weight gain, respectively. In general, the results indicated that water uptake and impact properties were affected by thickness and less by water type. Impact properties of prolonged immersed specimens reduced remarkably, and intense failure modes detected almost in all cases. The least sensitive to impact damage were wet specimens with 9 mm thickness as they indicated similar maximum load and absorbed energy for different impact energies.

Response and failure modes of biaxial warp-knitted flexible composite subject to low-velocity impact

2021 ◽  
pp. 152808372110154
Author(s):  
Ziyu Zhao ◽  
Tianming Liu ◽  
Pibo Ma
Keyword(s):  
Impact Energy ◽  
Linear Density ◽  
Failure Modes ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Minor Effect ◽  
Low Velocity ◽  
Velocity Impact ◽  
Flexible Composites ◽  
The Impact

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.

Experimental Analysis for the Effect of Impactor Geometry on Carbon Reinforced Composite Materials

2017 ◽  
Vol 25 (9) ◽  
pp. 677-682 ◽  
Author(s):  
Faruk Elaldi ◽  
Busra Baykan ◽  
Can Akto
Keyword(s):  
Composite Materials ◽  
Carbon Fibre ◽  
Composite Plates ◽  
High Strength ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Damage Area ◽  
Reinforced Composite ◽  
Contact Surfaces ◽  
The Impact

For the last three decades, composites have become very preferable materials to be used in the automotive industry, structural parts of aircraft and military systems and spacecraft, due to their high strength and modulus. Composite materials are sometimes exposed to invisible or visible damage due to impact loading during their service life. In this study, the effect of impactor geometry with four different contact surfaces on woven carbon fibre-reinforced composite plates having three different thicknesses are investigated. In the first stage, composite plates were manufactured with the ply orientations of [45/-45/0/90/45/-45]2s, [45/-45/0/90/45/-45]3s, [45/-45/0/90/45/-45]4s based on conventional usage. In the second stage, carbon fibre-reinforced composite test panels were exposed to low velocity impact tests to obtain force-time, energy-time and force-displacement curves. Finally, semi and full penetration of composite panels and damage magnitude were determined. It was found that the impactor geometries with lower contact surfaces such as conical and ogive types were much more penetrative on composite plates than the other geometries, but they caused larger damage area in the vicinity of the impact point.

Low Velocity Impact on Woven Kenaf Fiber Reinforced Composites

2014 ◽  
Vol 629 ◽  
pp. 503-506 ◽  
Author(s):  
Al Emran Ismail ◽  
M.A. Hassan
Keyword(s):  
Impact Velocity ◽  
Composite Plates ◽  
Fiber Reinforced Composites ◽  
Low Velocity Impact ◽  
Reinforced Composites ◽  
Low Velocity ◽  
Kenaf Fiber ◽  
Velocity Impact ◽  
The Impact ◽  
Woven Kenaf

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.

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