scholarly journals Permeability and compaction behaviour of air-texturised glass fibre rovings: A characterisation study

2020 ◽  
Vol 54 (27) ◽  
pp. 4241-4252 ◽  
Author(s):  
Michael Sandberg ◽  
Ayyoub Kabachi ◽  
Maximilian Volk ◽  
Filip Bo Salling ◽  
Paolo Ermanni ◽  
...  
Keyword(s):  
Glass Fibre ◽  
Volume Fraction ◽  
Compaction Pressure ◽  
Single Step ◽  
Elastic Response ◽  
Fibre Direction ◽  
Degree Of Anisotropy ◽  
Compaction Behaviour

Air-texturisation is a process that adds bulkiness to bundles of fibres. In this study, the permeability and compaction behaviour of air-texturised glass fibre rovings are experimentally characterised and compared to conventional unidirectional rovings. Based on radial impregnation experiments and single-step compaction/decompaction tests, the following main findings are highlighted: Compared to conventional unidirectional-rovings, the normalised permeability of the air-texturised rovings was approximately three times higher along the fibre direction and 40 times higher transverse to the fibre direction. Accordingly, the degree of anisotropy was approximately one magnitude lower. At a compaction pressure of 1 and 5 bar, the air-texturised rovings were compacted to a volume fraction of [Formula: see text] and 0.43, respectively, which was approximately 30% lower than the volume fraction achieved for the conventional unidirectional-rovings. Finally, it was observed that the decompaction of air-texturised rovings exhibits a more distinct elastic response when unloaded.

Orthotropic Characteristics of Glass-Fibre-Epoxy Laminates under Plane Stress

1973 ◽  
Vol 15 (2) ◽  
pp. 102-108 ◽  
Author(s):  
R. M. Ogorkiewicz
Keyword(s):  
Tensile Strength ◽  
Epoxy Resin ◽  
Uniaxial Tension ◽  
Plane Stress ◽  
Glass Fibre ◽  
Orthotropic Material ◽  
Glass Fibres ◽  
Degree Of Anisotropy

Deformational characteristics of laminates of unidirectionally arranged glass fibres and epoxy resin under plane stress are shown to correspond very closely under uniaxial tension and, to a lesser extent, under shear to the theroetical pattern of stiffness of an orthotropic material. The anisotropy in stiffness is also shown to be accompanied by an even greater degree of anisotropy in tensile strength.

scholarly journals Higher-Order Thermo-Elastic Analysis of FG-CNTRC Cylindrical Vessels Surrounded by a Pasternak Foundation

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 79 ◽  
Author(s):  
Masoud Mohammadi ◽  
Mohammad Arefi ◽  
Rossana Dimitri ◽  
Francesco Tornabene
Keyword(s):  
Deformation Theory ◽  
Volume Fraction ◽  
Effective Properties ◽  
Shear Deformation Theory ◽  
Pressure Vessels ◽  
Functionally Graded ◽  
Elastic Response ◽  
Governing Equations ◽  
Third Order ◽  
Reinforced Composite

This study analyses the two-dimensional thermo-elastic response of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) cylindrical pressure vessels, by applying the third-order shear deformation theory (TSDT). The effective properties of FG-CNTRC cylindrical pressure vessels are computed for different patterns of reinforcement, according to the rule of mixture. The governing equations of the problem are derived from the principle of virtual works and are solved as a classical eigenproblem under the assumption of clamped supported boundary conditions. A large parametric investigation aims at showing the influence of some meaningful parameters on the thermo-elastic response, such as the type of pattern, the volume fraction of CNTs, and the Pasternak coefficients related to the elastic foundation.

Pressurized Infusion: A New and Improved Liquid Composite Molding Process

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
M. Akif Yalcinkaya ◽  
Gorkem E. Guloglu ◽  
Maya Pishvar ◽  
Mehrad Amirkhosravi ◽  
E. Murat Sozer ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Composite Laminates ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Compaction Pressure ◽  
External Pressure ◽  
Void Content ◽  
Liquid Composite Molding ◽  
Molding Process ◽  
Fiber Volume

Vacuum-assisted resin transfer molding (VARTM) has several inherent shortcomings such as long mold filling times, low fiber volume fraction, and high void content in fabricated laminates. These problems in VARTM mainly arise from the limited compaction of the laminate and low resin pressure. Pressurized infusion (PI) molding introduced in this paper overcomes these disadvantages by (i) applying high compaction pressure on the laminate by an external pressure chamber placed on the mold and (ii) increasing the resin pressure by pressurizing the inlet resin reservoir. The effectiveness of PI molding was verified by fabricating composite laminates at various levels of chamber and inlet pressures and investigating the effect of these parameters on the fill time, fiber volume fraction, and void content. Furthermore, spatial distribution of voids was characterized by employing a unique method, which uses a flatbed scanner to capture the high-resolution planar scan of the fabricated laminates. The results revealed that PI molding reduced fill time by 45%, increased fiber volume fraction by 16%, reduced void content by 98%, improved short beam shear (SBS) strength by 14%, and yielded uniform spatial distribution of voids compared to those obtained by conventional VARTM.

Misalignment Error in Cancellous Bone Apparent Elastic Modulus Depends on Bone Volume Fraction and Degree of Anisotropy

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Matthew B. L. Bennison ◽  
A. Keith Pilkey ◽  
W. Brent Lievers
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Cancellous Bone ◽  
Volume Fraction ◽  
Experimental Studies ◽  
Bone Volume ◽  
Bone Volume Fraction ◽  
Skeletal Site ◽  
Degree Of Anisotropy ◽  
Misalignment Error

Abstract Cancellous bone is an anisotropic structure with architectural and mechanical properties that vary due to both skeletal site and disease state. This anisotropy means that, in order to accurately and consistently measure the mechanical properties of cancellous bone, experiments should be performed along the primary mechanical axis (PMA), that is, the orientation in which the mechanical properties are at their maximum value. Unfortunately, some degree of misalignment will always be present, and the magnitude of the resulting error is expected to be architecture dependent. The goal of this work is to quantify the dependence of the misalignment error, expressed in terms of change in apparent elastic modulus (ΔE), on both the bone volume fraction (BV/TV) and the degree of anisotropy (DA). Finite element method (FEM) models of bovine cancellous bone from five different skeletal sites were created at 5 deg and 20 deg from the PMA determined for each region. An additional set of models was created using image dilation/erosion steps in order to control for BV/TV and better isolate the effect of DA. Misalignment error was found to increase with increasing DA and decreasing BV/TV. At 5 deg misaligned from the PMA, error is relatively low (<5%) in all cases but increases to 8–24% error at 20 deg. These results suggest that great care is needed to avoid introducing misalignment error into experimental studies, particularly when studying regions with high anisotropy and/or low bone volume fraction, such as vertebral or osteoporotic bone.

Effects of Mechanical Vibration on Double Curvature Creep Aging Forming of 2124 Aluminum Alloy

2018 ◽  
Vol 913 ◽  
pp. 83-89
Author(s):  
Yu Wang ◽  
Yun Lai Deng ◽  
Jin Zhang ◽  
Yong Zhang ◽  
Xin Ming Zhang
Keyword(s):  
Aluminum Alloy ◽  
Creep Deformation ◽  
Volume Fraction ◽  
Mechanical Vibration ◽  
Three Dimensional ◽  
Forming Process ◽  
Double Curvature ◽  
Vibration Field ◽  
Precipitation Behaviour ◽  
Degree Of Anisotropy

This Paper studied the precipitation behaviour and creep deformation of 2124 aluminum alloy based on the concept of complex field. A mechanical vibration field was introduced into the creep aging forming process of 2124 aluminum alloy, and its effects on creep deformation, precipitations behaviour and mechanical properties under the condition of double curvature loading and aging temperature were investigated by three-dimensional scanning technique, TEM and tensile test, respectively. The results showed that the spring back value along the rolling and transverse direction presented after creep aging forming were reduced by 25% and 15% respectively. The volume fraction of precipitates increased and distributed more densely and uniformly. Meanwhile, the yield stress improved by 15MPa and the degree of anisotropy decreased by 17% with mechanical vibration field applied to the manufacturing process.

Densification Behavior of Metal Powder Under Uniaxial Cold Compaction

2010 ◽  
Author(s):  
Mostafa Darroudi ◽  
Hojat Ghassemi ◽  
Mahmoud Akbari Baseri
Keyword(s):  
Finite Element ◽  
Metal Powder ◽  
Volume Fraction ◽  
Compaction Pressure ◽  
Solid Volume Fraction ◽  
Powder Compaction ◽  
Wall Friction ◽  
Isotropic Hardening ◽  
Spherical Powder ◽  
Von Mises

Metal powder compaction is a quite important process in Powder Metallurgy (PM) industry and it is widely applied in the manufacturing of key components in different fields. During metal powder compaction, the solid volume fraction changes and many mechanical characteristics become different. The Finite Element simulation provides a flexible and efficient approach for the researches of this process and its complicated mechanical behaviors. In this paper, several 2D finite element spherical powder compaction models are generated. Different particle arrangements are build up and different friction coefficients are set to the inter-particle contacts and die wall contact for a certain arrangement. The Von Mises yield surface with isotropic hardening plasticity model is applied in the simulation and the displacement controlled load is used to compress the structure up to 25% of die height. Results show that the die wall friction increases compaction pressure but inter-particle friction has negligible effect.

scholarly journals Effect Of SiC Particles On Sinterability Of Al-Zn-Mg-Cu P/M Alloy

2015 ◽  
Vol 60 (2) ◽  
pp. 1383-1385 ◽  
Author(s):  
H. Rudianto ◽  
G.J. Jang ◽  
S.S. Yang ◽  
Y.J. Kim ◽  
I. Dlouhy
Keyword(s):  
Alloy Powder ◽  
Volume Fraction ◽  
Compaction Pressure ◽  
High Volume ◽  
Liquid Phase Sintering ◽  
Chemical Compositions ◽  
Sic Particles ◽  
Powder Sintering ◽  
Ultra High Purity ◽  
Dual Action

Abstract Premix Al-5.5Zn-2.5Mg-0.5Cu alloy powder was analyzed as matrix in this research. Gas atomized powder Al-9Si with 20% volume fraction of SiC particles was used as reinforcement and added into the alloy with varied concentration. Mix powders were compacted by dual action press with compaction pressure of 700 MPa. High volume fraction of SiC particles gave lower green density due to resistance of SiC particles to plastic deformation during compaction process and resulted voids between particles and this might reduce sinterability of this mix powder. Sintering was carried out under ultra high purity nitrogen gas from 565°-580°C for 1 hour. High content of premix Al-5.5Zn-2.5Mg-0.5Cu alloy powder gave better sintering density and reached up to 98% relative. Void between particles, oxide layer on aluminum powder and lower wettability between matrix and reinforcement particles lead to uncompleted liquid phase sintering, and resulted on lower sintering density and mechanical properties on powder with high content of SiC particles. Mix powder with wt90% of Alumix 431D and wt10% of Al-9Si-vf20SiC powder gave higher tensile strength compare to another mix powder for 270 MPa. From chemical compositions, sintering precipitates might form after sintering such as MgZn2, CuAl2 and Mg2Si. X-ray diffraction, DSC-TGA, and SEM were used to characterize these materials.

Effect of combined fatigue and hygrothermal loading on structural properties of E-glass/polymers

2016 ◽  
Vol 231 (18) ◽  
pp. 3382-3392 ◽  
Author(s):  
Abhineet Saini ◽  
Rahul Chhibber ◽  
A Chattopadhyay
Keyword(s):  
Glass Fibre ◽  
Volume Fraction ◽  
Cyclic Fatigue ◽  
Standard Test ◽  
Reinforced Polymers ◽  
Tropical Environments ◽  
Tropical Conditions ◽  
Different Temperatures ◽  
Glass Fibre Reinforced ◽  
Structural Tests

The paper discusses the potential ingress and combined effect of moisture and temperature on pre-fatigued glass fibre-reinforced polymers standard test specimens. An experimental investigation was conducted to analyse the behaviour of glass fibre-reinforced polymers’ in environmental conditions similar to that of tropical environments. The standard pre-fatigued glass fibre-reinforced polymers specimens were subjected to varying hygrothermal conditions: three different temperatures, i.e. natural bath, 45 ℃ and 55 ℃ to study the degradation in strength and related properties. Several macro-structural and micro-structural tests were conducted to determine the damage. The effect of these conditions on characteristics such as diffusivity, weight gain, resin volume fraction, conductivity and deterioration of ultimate tensile strength was determined. The maximum reduction in strength is found to be approximately 39% for the specimen exposed to 55 ℃ water bath for 60 days. This study shall be helpful in estimating the characteristics of glass fibre-reinforced polymers composites subjected to cyclic fatigue loads in the tropical conditions.

Sign in / Sign up

Export Citation Format

Share Document