18 research outputs found
Finite element analysis of hypervelocity impact behaviour of CFRP-Al/HC sandwich panel
The mechanical response of CFRP-Al/HC (carbon fibre-reinforced/epoxy composite face sheets with Al honeycomb core) sandwich panels to hyper-velocity impact (up to 1 km/s) is studied using a finite-element model developed in ABAQUS/Explicit. The intraply damage of CFRP face sheets is analysed by mean of a user-defined material model (VUMAT) employing a combination of Hashin and Puck criteria, delamination modelled using cohesive-zone elements. The damaged Al/HC core is assessed on the basis of a Johnson Cook dynamic failure model while its hydrodynamic response is captured using the Mie-Gruneisen equation of state. The results obtained with the developed finite-element model showed a reasonable correlation to experimental damage patterns. The surface peeling of both face sheets was evident, with a significant delamination around the impact location accompanied by crushing HC core
Experimental and Numerical Investigations in Conventional and Ultrasonically Assisted Drilling of CFRP Laminate
AbstractCarbon fiber-reinforced plastic (CFRP) composites are attractive for many industrial applications due to their superior properties. The parts made from CFRP are usually manufactured to a near-net shape; however, various machining processes, such as drilling, are often required to facilitate component assemblies. Conventional Drilling (CD) of CFRP induces high stresses in the vicinity of the drilled hole; along with high thrust forces on a drilling tool. An advanced drilling technique known as Ultrasonically Assisted Drilling (UAD) has been used to demonstrate its several advantages over CD including a reduced thrust force. A 3D finite element (FE) models simulating CD and UAD techniques for drilling in CFRP laminates were developed using the general-purpose FE software ABAQUS/Explicit. The numerical results obtained with the FE model were found to be in a good agreement with the experimental data
Effect of ultrasonically-assisted drilling on carbon-fibre-reinforced plastics
This research focuses on the effect of ultrasonically-assisted drilling (UAD) on carbon fibre-reinforced plastics. High-frequency vibration was used to excite a drill bit during its standard operation. An extensive experimental study of drilling forces, temperature, chip formation, surface finish, circularity, delamination and tool wear was conducted using ∅3 mm drill and presented here. UAD showed a significant improvement in drill quality when compared to conventional drilling processes. A finite-element study was also conducted to understand the nature of drilling-force reduction in UAD
Ballistic damage in hybrid composite laminates
Ballistic damage of hybrid woven-fabric composites made of plain-weave E-glass-fabric/epoxy and 8H satin-weave T300 carbon-fabric/epoxy is studied using a combination of experimental tests, microstructural studies and finite-element (FE) analysis. Ballistic tests were conducted with a single-stage gas gun. Fibre damage and delamination were observed to be dominating failure modes. A ply-level FE model was developed, with a fabric-reinforced ply modelled as a homogeneous orthotropic material with capacity to sustain progressive stiffness degradation due to fibre/matrix cracking, fibre breaking and plastic deformation under shear loading. Simulated damage patterns on the front and back faces of fabric-reinforced composite plates provided an insight into their damage mechanisms under ballistic loading
Effect of ultrasonically-assisted drilling on carbon-fibre-reinforced plastics
NOTICE: this is the author’s version of a work that was accepted for publication in
Journal of Sound and Vibration. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in
Journal of Sound and Vibration, Volume 333, Issue 23, 24 November 2014, Pages 5939–5952
DOI: 10.1016/j.jsv.2014.05.042This research focuses on the effect of ultrasonically-assisted drilling (UAD) on carbon fibre-reinforced plastics. High-frequency vibration was used to excite a drill bit during its standard operation. An extensive experimental study of drilling forces, temperature, chip formation, surface finish, circularity, delamination and tool wear was conducted using ∅3 mm drill and presented here. UAD showed a significant improvement in drill quality when compared to conventional drilling processes. A finite-element study was also conducted to understand the nature of drilling-force reduction in UAD
3D Finite Element Modelling of Cutting Forces in Drilling Fibre Metal Laminates and Experimental Hole Quality Analysis
Machining Glass fibre aluminium reinforced epoxy (GLARE) is cumbersome due to distinctively different mechanical and thermal properties of its constituents, which makes it challenging to achieve damage-free holes with the acceptable surface quality. The proposed work focuses on the study of the machinability of thin (~2.5 mm) GLARE laminate. Drilling trials were conducted to analyse the effect of feed rate and spindle speed on the cutting forces and hole quality. The resulting hole quality metrics (surface roughness, hole size, circularity error, burr formation and delamination) were assessed using surface profilometry and optical scanning techniques. A three dimensional (3D) finite-element (FE) model of drilling GLARE laminate was also developed using ABAQUS/Explicit to help understand the mechanism of drilling GLARE. The homogenised ply-level response of GLARE laminate was considered in the FE model to predict cutting forces in the drilling process
Impact and blast response of polymer matrix laminates- finite-element studies
Polymer matrix composites (PMCs) offer several advantages compared to
traditional metallic counterparts when employed in high-performance products
that need to be lightweight, yet strong enough to sustain harsh loading
conditions - such as aerospace components and protective structures in military
applications- armours, helmets, and fabrications retrofitted to transport vehicles
and bunkers. These are often subjected to highly dynamic loading conditions
under blast and ballistic impacts. Severe impact energy involved in these
dynamic loading events can initiate discrete damage modes in PMCs such as
matrix cracking, matrix splitting, delamination, fibre-matrix debonding, fibre
micro-buckling and fibre pull-out. Interaction of these damage modes can
severely reduce the load carrying capacity of such structures. This needs to be
understood to design structures with improved resistance to such loading. [Continues.
Finite element analysis of hypervelocity impact behaviour of CFRP-Al/HC sandwich panel
The mechanical response of CFRP-Al/HC (carbon fibre-reinforced/epoxy composite face sheets with Al honeycomb core) sandwich panels to hyper-velocity impact (up to 1 km/s) is studied using a finite-element model developed in ABAQUS/Explicit. The intraply damage of CFRP face sheets is analysed by mean of a user-defined material model (VUMAT) employing a combination of Hashin and Puck criteria, delamination modelled using cohesive-zone elements. The damaged Al/HC core is assessed on the basis of a Johnson Cook dynamic failure model while its hydrodynamic response is captured using the Mie-Gruneisen equation of state. The results obtained with the developed finite-element model showed a reasonable correlation to experimental damage patterns. The surface peeling of both face sheets was evident, with a significant delamination around the impact location accompanied by crushing HC core
Finite element analysis of hypervelocity impact behaviour of CFRP-Al/HC sandwich panel
The mechanical response of CFRP-Al/HC (carbon fibre-reinforced/epoxy composite face sheets with Al honeycomb core) sandwich panels to hyper-velocity impact (up to 1 km/s) is studied using a finite-element model developed in ABAQUS/Explicit. The intraply damage of CFRP face sheets is analysed by mean of a user-defined material model (VUMAT) employing a combination of Hashin and Puck criteria, delamination modelled using cohesive-zone elements. The damaged Al/HC core is assessed on the basis of a Johnson Cook dynamic failure model while its hydrodynamic response is captured using the Mie-Gruneisen equation of state. The results obtained with the developed finite-element model showed a reasonable correlation to experimental damage patterns. The surface peeling of both face sheets was evident, with a significant delamination around the impact location accompanied by crushing HC core
Ballistic damage in hybrid composite laminates
Ballistic damage of hybrid woven-fabric composites made of plain-weave E-glass- fabric/epoxy and 8H satin-weave T300 carbon-fabric/epoxy is studied using a combination of experimental tests, microstructural studies and finite-element (FE) analysis. Ballistic tests were conducted with a single-stage gas gun. Fibre damage and delamination were observed to be dominating failure modes. A ply-level FE model was developed, with a fabric-reinforced ply modelled as a homogeneous orthotropic material with capacity to sustain progressive stiffness degradation due to fibre/matrix cracking, fibre breaking and plastic deformation under shear loading. Simulated damage patterns on the front and back faces of fabric-reinforced composite plates provided an insight into their damage mechanisms under ballistic loading