Failure Modes of a Laminated Composite With Complaint Interlayers

2020 ◽  
Vol 88 (3) ◽  
Author(s):  
M. R. O’Masta ◽  
V. S. Deshpande
Keyword(s):  
Failure Mechanism ◽  
Failure Mode ◽  
Failure Modes ◽  
Volume Fraction ◽  
Flexural Rigidity ◽  
Laminated Composite ◽  
High Volume ◽  
Tensile Fracture ◽  
Reduced Order ◽  
Fe Simulations

Abstract Composites comprising a high-volume fraction of stiff reinforcements within a compliant matrix are commonly found in natural materials. The disparate properties of the constituent materials endow resilience to the composite, and here we report an investigation into some of the mechanisms at play. We report experiments and simulations of a prototype laminated composite system comprising silicon layers separated by polymer interlayers, where the only failure mechanism is the tensile fracture of the brittle silicon. Two failure modes are observed for such composites loaded in three-point bending: failure under the central roller in (i) the top ply (in contact with the roller) or (ii) the bottom ply (free surface). The former mode is benign with the beam retaining load carrying capacity, whereas the latter leads to catastrophic beam failure. Finite element (FE) simulations confirm this transition in failure mode and inform the development of a reduced order model. Good agreement is shown between measurements, FE simulations, and reduced order predictions, capturing the effects of material and geometric properties on the flexural rigidity, first ply failure mode, and failure load. A failure mechanism map for this system is reported that can be used to inform the design of such laminated composites.

Utility of 2D Finite Element Simulations for Predicting Effective Thermomechanical Properties of Particle-Reinforced Composites

2018 ◽  
Author(s):  
Kamran Makarian ◽  
Sridhar Santhanam
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Volume Fraction ◽  
Effective Properties ◽  
Coefficient Of Thermal Expansion ◽  
High Volume ◽  
Thermomechanical Properties ◽  
Reinforced Composites ◽  
Fe Simulations ◽  
Particle Reinforced Composites

In the last two decades, researchers have implemented two-dimensional (2D) Finite Element (FE) simulations of particle-reinforced composites for various purposes, including prediction of effective properties and failure modes. The present work aspires to examine the validity of the hypothesis that 2D FE simulations can provide accurate predictions for various thermomechanical properties of high volume fraction (VF) particle-reinforced composites. For this purpose, the random sequential adsorption (RSA) algorithm is implemented to generate FE simulations of various composites. The uniqueness in the methodology of the present work is in the generation of FE simulation of composites with more than two material types as reinforcement, as well as thorough and concurrent comparison of multiple thermal and mechanical properties. The adequacy of the simulations is verified statistically, and the results are compared to predictions from established schemes as well as certain experimental findings. These comparisons show that the predictive power of 2D FE simulations is lower for elastic properties, and higher for coefficient of thermal expansion (CTE) and thermal conductivity of particle-reinforced composites. The findings of this research can guide the researchers in making better decisions for implementing Finite Element Method (FEM) for designing high VF composites.

scholarly journals Mechanical properties and progressive failure characteristics of sandstone containing elliptical and square openings subjected to biaxial stress

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0246815
Author(s):  
Honggang Zhao ◽  
Haitao Sun ◽  
Dongming Zhang ◽  
Chao Liu
Keyword(s):  
Mechanical Properties ◽  
Failure Mode ◽  
Failure Modes ◽  
Biaxial Stress ◽  
Tensile Fracture ◽  
Biaxial Compression ◽  
Lateral Stress ◽  
Variable Theory ◽  
Failure Characteristics ◽  
Elliptical Opening

Two kinds of common tunnel shapes, i.e. elliptical opening and square opening were selected for biaxial compression tests, and the influences of two kinds of opening shapes on the mechanical properties, failure characteristics and failure modes of sandstone were compared and analyzed. The complex variable theory and mapping functions were used to obtain the analytical stress solution around elliptical and square openings. The results show that the stability of the specimen containing an elliptical opening was better than that of the specimen containing a square opening under the same lateral stress. Compared with the elliptical opening, the local damage was formed earlier in the square opening which might be caused by a higher stress concentration around the square opening. The stress distributions around openings were influenced by the opening shape and lateral stress coefficient. The top and bottom of square opening were more prone to tensile fracture, and the distribution range of tensile was larger than that of elliptical opening. When the opening failed, the intensity of square opening failure was weaker than that of elliptical opening. On the basis of the average frequency value and the rise angle value, the failure mode of specimen containing elliptical or square opening was distinguished. It was found that the mixed tension and shear failure dominated the failure of specimens with different opening shapes, and the number of shear cracks in the specimen containing a square opening was greater than that in the specimen containing an elliptical opening. The above method of judging failure mode by acoustic emission signals was well verified by the CT images of damaged specimens.

A Performance Study on Self-Piercing Riveting and Adhesive Hybrid Joints of Different Adhesive

2014 ◽  
Vol 887-888 ◽  
pp. 1261-1264
Author(s):  
Fu Long Liu ◽  
Xiao Cong He ◽  
Yu Qi Wang
Keyword(s):  
Failure Mechanism ◽  
Energy Absorption ◽  
Failure Mode ◽  
Failure Modes ◽  
Test Results ◽  
Performance Study ◽  
Strength Capacity ◽  
Hybrid Joints ◽  
Overall Performance ◽  
Tension Loading

This paper studied the performance of self-piercing riveting (SPR) and adhesive hybrid joints of different adhesive, including strength, capacity of energy absorption, failure mode and failure mechanism of the hybrid joints. The performances of SPR-adhesive hybrid joints were compared with SPR joints. SPR-adhesive hybrid joints and SPR joints were tested under a tension loading. The test results showed that adhesive have a function of improving the strength of SPR joints; however, the capacity of energy absorption of SPR joints was weakened. While the adhesive have no effect on the failure modes of SPR joints. When appropriate adhesive was selected, the overall performance of SPR-adhesive hybrid joints was superior to SPR joints. In a word, the combination of SPR and adhesive could get a well jointing structure.

scholarly journals KAJIAN EKSPERIMENTAL TENSILE PROPERTIES KOMPOSIT POLIESTER BERPENGUAT SERAT KARBON SEARAH HASIL MANUFAKTUR VACUUM INFUSION SEBAGAI MATERIAL STRUKTUR LSU

2018 ◽  
Vol 14 (1) ◽  
pp. 61
Author(s):  
Kosim Abdurohman ◽  
Aryandi Marta
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Tensile Test ◽  
Failure Mode ◽  
Modulus Of Elasticity ◽  
Failure Modes ◽  
Volume Fraction ◽  
Manufacturing Method ◽  
Vacuum Infusion

Vacuum infusion is a manufacturing method to improve mechanical properties of composite. Before apply this in LSU structure, it should be experimented using tensile test to know mechanical properties of the composite. Tensile test is an experimental to know tensile strength, modulus of elasticity, and failure modes of composite. Experimental process of CFRP composite using unidirectional carbon fiber and polyester matrix was done using vacuum infusion technology, strart from specimens preparation until testing steps. Manufacturing results gave the values of composite density and thickness; mass and volume fraction of fiber and matrix materials. Specimens and testing process are refer to ASTM D3039 tensile test standard for composite matrix polymers. The testing results showed 1011.67 MPa ultimate tensile strength, 59074.96 MPa modulus of elasticity, and SGV (long spliting, gage, various) failure mode . ABSTRAKVacuum infusion merupakan salah satu metode manufaktur yang digunakan untuk meningkatkan sifat mekanik komposit. Untuk mengaplikasikan metode ini dalam pembuatan struktur LAPAN Surveillance UAV (LSU), perlu diketahui terlebih dahulu sifat mekanik dari komposit hasil metode ini secara eksperimen. Salah satu eksperimen yang dilakukan yaitu pengujian tarik untuk mendapatkan tensile strength, modulus elastisitas, dan failure mode yang terjadi pada komposit. Eksperimen dilakukan terhadap komposit CFRP menggunakan material serat karbon searah (UD) 0⁰ dan matriks poliester dibuat dengan metode vacuum infusion mulai dari tahap preparasi sampai tahap pengujian. Dari hasil manufaktur didapat nilai densitas dan ketebalan komposit serta fraksi massa dan fraksi volume material penyusun komposit. Spesimen dan proses pengujian mengikuti standar ASTM D3039 yang merupakan standar pengujian tarik untuk komposit dengan matriks polimer. Hasil pengujian menunjukkan nilai ultimate tensile strength 1011,67 MPa, modulus elastisitas 59074,96 MPa, dan failure mode SGV (Long Spliting, Gage, Various).

Investigation on the Effect of Resin Content on Buckling of Laminated Composite Plates

2014 ◽  
Vol 1035 ◽  
pp. 212-218
Author(s):  
Qi You Cheng ◽  
Jian Ping Huang ◽  
Ai Min Ling ◽  
Zhi Zhuang Feng
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Failure Modes ◽  
Volume Fraction ◽  
Laminated Composite ◽  
Composite Plates ◽  
Buckling Load ◽  
Laminated Composite Plates ◽  
Element Analysis ◽  
The Stability

Aerospace applications of composites involve components that are relatively thin plate or shell like structures, thus requiring the consideration of buckling as one of the many possible failure modes. To study the effect of the resin volume fraction on stability of composites, a finite element method based on micromechanics and classical lamination theory has been established to compute buckling loads of simply supported symmetric laminated composite plates subjected to the load of in-plane axial compress and shear load, respectively. The analysis procedure includes a Micromechanical finite element analysis that predicts the elastic modulus of lamina and a finite element linear buckling analysis that predicts buckling load of the composite plates. Three kinds of resin volume fraction that are equal to 44 percent, 47 percent, and 50 percent respectively are considered. The results show that the resin volume fraction has obvious influence on the stability of composite plate. The plate exhibits a relatively large increase in buckling load, about 12 percent, when the resin volume fraction increases by 3 percent. It is finds that the bending stiffness that has an obvious influence on the stability is an incremental function of elastic modulus and cubic thickness. The elastic modulus will be decreased slightly with the increase of resin volume fraction. However, the thickness of the plates is proportional to resin volume fraction.

Novel cellular perlite–epoxy foams: Effect of density on mechanical properties

2016 ◽  
Vol 53 (4) ◽  
pp. 425-442 ◽  
Author(s):  
Haleh Allameh-Haery ◽  
Erich Kisi ◽  
Thomas Fiedler
Keyword(s):  
Elastic Modulus ◽  
Failure Modes ◽  
Shear Failure ◽  
Volume Fraction ◽  
Volcanic Glass ◽  
Effective Elastic Modulus ◽  
High Volume ◽  
Density Range ◽  
Longitudinal Splitting ◽  
Closed Cell

A novel type of economical lightweight foam with density from 0.15 to 0.45 g/cm3 was made from a high volume fraction of expanded volcanic glass (perlite) in an epoxy matrix. The compressive strength, effective elastic modulus, and modulus of toughness of the foams all increased with the foam density. The strength increased linearly, peaking at 1.7 MPa whereas the effective elastic modulus and modulus of toughness increased at parabolically increasing and decreasing rates, respectively. The specific compressive stress of the newly developed foam in the density range of 0.3–0.44 g/cm3 is comparable with foams made from alumina, aluminium–silicon carbide, closed cell phenolic resin, and closed cell polypropylene. Post-test SEM observations coupled with photogrammetry during the tests revealed three different failure modes: longitudinal splitting, shear failure, and compression failure were present over the whole density range. The material was found to be a good candidate for the stiffening cores within sandwich panels.

scholarly journals KAJIAN EKSPERIMENTAL TENSILE PROPERTIES KOMPOSIT POLIESTER BERPENGUAT SERAT KARBON SEARAH HASIL MANUFAKTUR VACUUM INFUSION SEBAGAI MATERIAL STRUKTUR LSU

2016 ◽  
Vol 14 (1) ◽  
pp. 61 ◽  
Author(s):  
Kosim Abdurohman ◽  
Aryandi Marta
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Tensile Test ◽  
Failure Mode ◽  
Modulus Of Elasticity ◽  
Failure Modes ◽  
Volume Fraction ◽  
Manufacturing Method ◽  
Vacuum Infusion

Vacuum infusion is a manufacturing method to improve mechanical properties of composite. Before apply this in LSU structure, it should be experimented using tensile test to know mechanical properties of the composite. Tensile test is an experimental to know tensile strength, modulus of elasticity, and failure modes of composite. Experimental process of CFRP composite using unidirectional carbon fiber and polyester matrix was done using vacuum infusion technology, strart from specimens preparation until testing steps. Manufacturing results gave the values of composite density and thickness; mass and volume fraction of fiber and matrix materials. Specimens and testing process are refer to ASTM D3039 tensile test standard for composite matrix polymers. The testing results showed 1011.67 MPa ultimate tensile strength, 59074.96 MPa modulus of elasticity, and SGV (long spliting, gage, various) failure mode . Abstrak Vacuum infusion merupakan salah satu metode manufaktur yang digunakan untuk meningkatkan sifat mekanik komposit. Untuk mengaplikasikan metode ini dalam pembuatan struktur LAPAN Surveillance UAV (LSU), perlu diketahui terlebih dahulu sifat mekanik dari komposit hasil metode ini secara eksperimen. Salah satu eksperimen yang dilakukan yaitu pengujian tarik untuk mendapatkan tensile strength, modulus elastisitas, dan failure mode yang terjadi pada komposit.Eksperimen dilakukan terhadap komposit CFRP menggunakan material serat karbon searah (UD) 0⁰ dan matriks poliester dibuat dengan metode vacuum infusion mulai dari tahap preparasi sampai tahap pengujian. Dari hasil manufaktur didapat nilai densitas dan ketebalan komposit serta fraksi massa dan fraksi volume material penyusun komposit. Spesimen dan proses pengujian mengikuti standar ASTM D3039 yang merupakan standar pengujian tarik untuk komposit dengan matriks polimer. Hasil pengujian menunjukkan nilai ultimate tensile strength 1011,67 MPa, modulus elastisitas 59074,96 MPa, dan failure mode SGV (Long Spliting, Gage, Various).

Morphology, Distribution and Identification of Micro-Constituents Along Grain Boundaries in Nickel-Base Alloys

1973 ◽  
Vol 31 ◽  
pp. 176-177
Author(s):  
D. E. Fornwalt ◽  
A. R. Geary ◽  
B. H. Kear
Keyword(s):  
Electron Microscope ◽  
Grain Boundaries ◽  
Volume Fraction ◽  
Rupture Life ◽  
Stress Rupture ◽  
High Volume ◽  
Precipitate Morphology ◽  
Stress Rupture Life ◽  
Nickel Base ◽  
Scanning Electron

A systematic study has been made of the effects of various heat treatments on the microstructures of several experimental high volume fraction γ’ precipitation hardened nickel-base alloys, after doping with ∼2 w/o Hf so as to improve the stress rupture life and ductility. The most significant microstructural chan§e brought about by prolonged aging at temperatures in the range 1600°-1900°F was the decoration of grain boundaries with precipitate particles.Precipitation along the grain boundaries was first detected by optical microscopy, but it was necessary to use the scanning electron microscope to reveal the details of the precipitate morphology. Figure 1(a) shows the grain boundary precipitates in relief, after partial dissolution of the surrounding γ + γ’ matrix.

HOT CORROSION OF CERIA-YTTRIA STABILIZED ZIRCONIA PLASMA SPRAYED THERMAL BARRIER COATING BY EUTECTIC VANDIUM PENTAOXIDE-SODIUM SULFATE

2018 ◽  
Vol 18 (1) ◽  
pp. 182-192 ◽  
Author(s):  
Mohammed J Kadhim ◽  
Mohammed H Hafiz ◽  
Maryam A Ali Bash
Keyword(s):  
Thermal Barrier Coating ◽  
Hot Corrosion ◽  
Monoclinic Phase ◽  
Volume Fraction ◽  
High Volume ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Plan View ◽  
Barrier Coating ◽  
Plasma Sprayed

The high temperature corrosion behavior of thermal barrier coating (TBC) systemconsisting of IN-738 LC superalloy substrate, air plasma sprayed Ni24.5Cr6Al0.4Y (wt%)bond coat and air plasma sprayed ZrO2-20 wt% ceria-3.6 wt% yttria (CYSZ) ceramic coatwere characterized. The upper surfaces of CYSZ covered with 30 mg/cm2 , mixed 45 wt%Na2SO4-55 wt% V2O5 salt were exposed at different temperatures from 800 to 1000 oC andinteraction times from 1 up to 8 h. The upper surface plan view of the coatings wereidentified for topography, roughness, chemical composition, phases and reaction productsusing scanning electron microscopy, energy dispersive spectroscopy, talysurf, and X-raydiffraction. XRD analyses of the plasma sprayed coatings after hot corrosion confirmed thephase transformation of nontransformable tetragonal (t') into monoclinic phase, presence ofYVO4 and CeVO4 products. Analysis of the hot corrosion CYSZ coating confirmed theformation of high volume fraction of YVO4, with low volume fractions of CeOV4 and CeO2.The formation of these compounds were combined with formation of monoclinic phase (m)from transformation of nontransformable tetragonal phase (t').

Combine Nanoprobing Technique with Difference Analysis to Identify Nonvisual Failures

2006 ◽  
Author(s):  
Cha-Ming Shen ◽  
Tsan-Cheng Chuang ◽  
Jie-Fei Chang ◽  
Jin-Hong Chou
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Electrical Characteristic ◽  
The Novel ◽  
Difference Analysis ◽  
Original Idea ◽  
Deductive Method ◽  
Complete Measurement

Abstract This paper presents a novel deductive methodology, which is accomplished by applying difference analysis to nano-probing technique. In order to prove the novel methodology, the specimens with 90nm process and soft failures were chosen for the experiment. The objective is to overcome the difficulty in detecting non-visual, erratic, and complex failure modes. And the original idea of this deductive method is based on the complete measurement of electrical characteristic by nano-probing and difference analysis. The capability to distinguish erratic and invisible defect was proven, even when the compound and complicated failure mode resulted in a puzzling characteristic.

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