A Study of Hybrid Composite Sandwich Beam

2019 ◽  
Author(s):  
Shah Alam ◽  
Guoqiang Li
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Experimental Results ◽  
Core Material ◽  
Sandwich Beams ◽  
Premature Failure ◽  
Element Modeling ◽  
Composite Sandwich ◽  
The Core ◽  
Linear Variable Displacement Transducer

Abstract This study presents the testing and numerical modeling results of composite sandwich beams. The sandwich beams are constructed from balsa wood in the core and high strength steel wire and E-glass fiber reinforced polymer composite in the facings. The testing of these beams is performed using a monotonic static four-point loading to failure in accordance with ASTM C393-00. Local strain distribution in the mid-span of the beams is obtained using strain gauges. Mid-span deflections of the beams are real-time measured using linear variable displacement transducer (LVDT). From the experimental results, flexural properties of the beams are calculated, including bending stiffness, bending strength, core shear strength, and facing modulus, core modulus, etc. The experimental results have shown that the beams have all failed in the compression zone by local buckling of the top face and shear of the core. The bottom skin does not exhibit any type of premature failure or distress. No bond failure of the composite in the tension zone is observed in any of the tested beams. Finite element modeling of the beam has been conducted using ANSYS. The mechanical properties of the skin and core material used in finite element modeling have been determined by testing of coupons. The predicted results are compared to experimental results, with a reasonable agreement.

scholarly journals Nonlinear Stress and Deformation Behaviour of Composite Sandwich Beams

2008 ◽  
Vol 13-14 ◽  
pp. 91-98 ◽  
Author(s):  
E.E. Gdoutos ◽  
I.M. Daniel
Keyword(s):  
Experimental Results ◽  
Core Material ◽  
Sandwich Beams ◽  
Stress Strain ◽  
Normal Stress Distribution ◽  
Nonlinear Load ◽  
Composite Sandwich ◽  
The Core ◽  
Nonlinear Stress ◽  
Load Displacement

The nonlinear load-displacement and normal stress distribution in composite sandwich beams made of unidirectional carbon/epoxy facings and PVC foam cores under bending was studied. The carbon/epoxy after an initial linear response exhibits a stiffening nonlinearity in tension and a softening nonlinearity in compression with the longitudinal strength in tension higher than that in compression. The foam core also presents a nonlinear stress-strain response. It was obtained that the load-displacement behaviour of the beam, after an initial linear part, is not linear. This behavior was modeled by an incremental strength of materials nonlinear analysis. The theoretical predictions were in good agreement with the experimental results. Furthermore, it was obtained that the neutral axis of sandwich beams under bending does not pass through the centroid of the cross section, but is displaced toward the tensile side of the beam. Experimental results by moiré measurements of the in-plane horizontal displacements of the core material corroborated the analytical predictions. These findings imply higher compressive and smaller tensile stresses in the core, than those predicted for facings with identical stress-strain behaviour in tension and compression, and should be taking into consideration in the failure analysis of sandwich beams.

Investigation of elastomeric foam response applied as core for composite sandwich beams through progressive failure of the beams

2017 ◽  
Vol 21 (2) ◽  
pp. 604-638
Author(s):  
AR Nazari ◽  
MZ Kabir ◽  
H Hosseini Toudeshky
Keyword(s):  
Finite Element ◽  
Carrying Capacity ◽  
Progressive Failure ◽  
Core Material ◽  
Foam Core ◽  
Sandwich Beams ◽  
Load Carrying Capacity ◽  
Composite Sandwich ◽  
The Core ◽  
Load Carrying

In this paper an elastomeric foam is applied as core for the composite sandwich beams and load carrying capacity, load–deflection response, and progressive failure are examined through experimental and finite element studies. The objective of this study is to assess the efficiency of elastomeric foam-cored sandwich (EFCS) beams relative to crushable foam-cored sandwich (CFCS) beams. The experimental program consists of two phases. In the first phase, some characterization tests are conducted on the constituent materials of the sandwich beams such as tension, compression, and shear tests on the foam and bending test on the composite beams utilized as skins. Then in the second phase, the performance of the sandwich beams is examined under bending conditions. The load carrying behavior of the sandwich beams is considered dependent on two main features of the constituent materials: (1) the hyperelastic behavior of the foam core and (2) the progressive damage of the composite skins. These characteristics are simulated by the finite element models. Due to elastomeric rather than crushable deformation of the applied foam as the core, the conventional damage modes of the CFCS beams associated to the brittleness of the core material are omitted through load carrying capacity of the EFCS beams. So in the recent sandwich beams by omission of the core failure modes and utilization of compressive residual strength of the top composite skin, considerable energy is absorbed prior to failure of the bottom composite skin. By simulation of the test specimens using FE models, the response of the foam applied as core for the sandwich beams through progressive failure of the beams is investigated. The results show that the elastomeric foam core can provide superior features for the sandwich components especially for the cases in which high energy absorption capacity is required.

Investigation of tensile and flexural behavior of biaxial and rib 1 × 1 weft-knitted composite using experimental tests and multi-scale finite element modeling

2019 ◽  
Vol 53 (23) ◽  
pp. 3201-3215 ◽  
Author(s):  
Reza Hessami ◽  
Aliasghar Alamdar Yazdi ◽  
Abbas Mazidi
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Experimental Results ◽  
Flexural Behavior ◽  
Bending Tests ◽  
Three Point Bending ◽  
Element Modeling ◽  
Multi Scale ◽  
Scale Modeling ◽  
Composite Samples

In this study, tensile and flexural behavior of biaxial and rib weft-knitted composite is obtained numerically and experimentally. Multi-scale finite element modeling is employed to simulate the tensile and flexural behavior of composite samples. In the finite element modeling, the geometry of a unit cell of each fabric is initially modeled in ABAQUS software, and then periodic boundary conditions were applied to a unit cell. The stiffness matrix for each structure was obtained by a python code via meso scale modeling and used as input data for the macro modeling. To validate the numerical model, two types of weft-knitted fabrics (rib 1 × 1 and biaxial fabrics) are produced by a flat weft knitting machine. Epoxy resin is used to construct composite by the vacuum injection process (VIP). After that, the tensile and three-point bending tests were applied to composite samples. The experimental results showed that tensile strength and tensile modulus of biaxial composites are greater than rib composites, in both wale and course directions. Moreover, in three-point bending test, biaxial composite showed more strength and more stiffness in comparison to rib composite. Finite element results were compared to experimental results in tensile and bending tests. The results showed that good agreement with experimental results in the linear section of tensile and flexural behavior of composites. Consequently, the current multi-scale modeling can be used to predict the stiffness matrix and mechanical behavior of complex composite structures such as knitted composites.

Finite Element Modeling of Cutting Force and Chip Formation During Thermally Assisted Machining of Ti6Al4V Alloy

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Yao Xi ◽  
Michael Bermingham ◽  
Gui Wang ◽  
Matthew Dargusch
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Cutting Force ◽  
Formation Process ◽  
Chip Formation ◽  
Cutting Forces ◽  
Experimental Results ◽  
Strongly Correlated ◽  
Element Modeling ◽  
Simulation Results

The improvement in machinability during thermally assisted turning of the Ti-6Al-4V alloy has been investigated using finite element modeling. A 2D thermally assisted turning model was developed and validated by comparing the simulation results with experimental results. The effect of workpiece temperature on the cutting force and chip formation process was examined. The predicted cutting forces and chip morphologies from the simulation strongly correlated with the experimental results. It was observed from the simulation that the chip forms after the coalescence of two deformed regions in the shear band and that the cyclic cutting forces are strongly related to this chip formation process.

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