Models for Fibrous Composites With Different Properties in Tension and Compression

1977 ◽  
Vol 99 (4) ◽  
pp. 344-349 ◽  
Author(s):  
C. W. Bert
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Mathematical Models ◽  
The Other ◽  
Reciprocal Relation ◽  
Angular Orientation ◽  
Compliance Matrix ◽  
Young’S Moduli ◽  
Elastic Composite ◽  
Tension And Compression

It has been observed that certain filamentary composite materials exhibit a different Poisson compliance when loaded transversely to the fibers than when loaded longitudinally (parallel to the fibers). In such cases the following widely used reciprocal relation is not satisfied: νLT/EL=νLT/ET where EL and ET are the L (longitudinal) and T (transverse) Young’s moduli and νLT and νTL are the Poisson’s ratios obtained from uniaxial loading in the L and T directions. Here two entirely different approaches are used to develop mathematical models of an elastic composite material behaving as described above. One method permits the compliance matrix to be unsymmetric but vary smoothly with the angular orientation. The other method, which is believed to be more valid, incorporates one set of symmetric compliances when the fibers are loaded in tension and a different set of symmetric compliances when the fibers are loaded in compression. The two different models are applied to some data for rubber reinforced by aramid (Kevlar) cord. For this composite, the above reciprocal relation is least satisfied, since νTL/ET is approximately 147 times νLT/EL.

Tailoring Composite Materials Through Optimal Selection of Their Constituents

1992 ◽  
Vol 114 (3) ◽  
pp. 451-458 ◽  
Author(s):  
H. M. Karandikar ◽  
F. Mistree
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Multiobjective Optimization ◽  
Material Selection ◽  
The Other ◽  
Economic Factors ◽  
Optimal Selection ◽  
Structural Applications ◽  
Design Requirements ◽  
Selection Of

The use of composite materials has provided designers with increased opportunities for tailoring structures and materials to meet load requirements and changing and demanding environments. This has led to their increased use in structural applications. As with traditional materials the selection of an appropriate material for a design is important. In case of design using composite materials the selection of a material consists of selecting a fiber-resin combination which meets all design requirements. This involves choosing the fiber, the resin, and the proportion of these two constituents in the composite material. The phrase “material selection” refers to the problem of laminate selection. This corresponds to the task of choosing a fiber and resin combination based on technical and economic factors. Materials tailoring, on the other hand, involves manipulating the composition of the composite material to achieve desired properties and it is the selection of a fiber and resin simultaneously but separately. In this paper we present, through an example, a multiobjective optimization-based method for assisting a designer in tailoring composite materials for specific technical and economic objectives.

scholarly journals Determination of Young’s Moduli of the Phases of Composite Materials Reinforced with Longitudinal Fibers, by Global Measurements

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1607
Author(s):  
Renata Ildikó Szavá ◽  
Ioan Szavá ◽  
Sorin Vlase ◽  
Arina Modrea
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Constitutive Law ◽  
Engineering Practice ◽  
Phase Component ◽  
Young’S Moduli ◽  
Transverse Isotropic ◽  
Materials Used ◽  
Independent Parameters

The properties of a composite material are determined by the properties of the constitutive materials. In engineering practice, there are many situations in which we have composite material, but we do not have information about the properties of each phase component. The measurements we can make in such cases are on the existing material, thus being able to determine, experimentally, the global physical properties of the composite. The possibility of realizing an estimate of the mechanical properties of each component poses a problem if we start from these measurements. The paper proposes a method to achieve this, starting from the theoretical estimates established in the literature, then illustrated by an example to determine the properties of wood. Wood is a transverse isotropic material and therefore the constitutive law has symmetries that are manifested in the decrease of the number of parameters that define the stress-strain liason, defined only by five independent parameters. The proposed method can be extended to a diversity of models and materials used in the study of composite materials.

scholarly journals Wear Study On Al-B4C Composite Material

2020 ◽  
Vol 3 (10) ◽  
pp. 56-58
Author(s):  
N. Pavan ◽  
Jaysaheel I. Harti ◽  
K. S. Harishanand
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Composite Materials ◽  
Operating Conditions ◽  
The Other ◽  
Wear Behaviour ◽  
Economical Aspect ◽  
Engineering Materials ◽  
Materials Used ◽  
Commercial Applications

There are various types of engineering materials used in both commercial as well as non-commercial applications, it becomes important to think about the life of the material, to prove about the economical aspect of the material. In order to increase the life, the conventional engineering materials fails in one or the other aspects. So the arrival of composite materials is important, which shows better mechanical properties than the regular engineering materials with lower weights. A study on the wear behaviour of a composite material (Al-B4C), under varying concentration of the reinforcement is made to understand the material usability under the cyclic operating conditions.

Hybrid polymer composite materials. Part 2. Preparation technology

2020 ◽  
pp. 8-13
Keyword(s):  
Composite Materials ◽  
Impact Toughness ◽  
Polymer Composites ◽  
The Other ◽  
Polymer Materials ◽  
Hybrid Polymer ◽  
Preparation Technology ◽  
Advantages And Disadvantages ◽  
Hybrid Polymer Composite ◽  
The One

The main methods (pressing and winding) of the processing of hybrid polymer composites to obtain items were examined. Advantages and disadvantages of the methods were noted. Good combinations of different-module fibers (carbon, glass, boron, organic) in hybrid polymer materials are described, which allow one to prepare materials with high compression strength on the one hand, and to increase fracture energy of samples and impact toughness on the other hand.

Study of the Composite Materials Optimal Structure Containing a Hollow Aluminum and Silica Microsphere Dependence on Humidity

2020 ◽  
Vol 12 ◽  
Author(s):  
Alexandra Atyaksheva ◽  
Yermek Sarsikeyev ◽  
Anastasia Atyaksheva ◽  
Olga Galtseva ◽  
Alexander Rogachev
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Strength Function ◽  
Theory And Practice ◽  
Optimal Structure ◽  
Optimal Size ◽  
Structure And Properties ◽  
Power Functions ◽  
Silica Microsphere ◽  
Heat Engineering

Aims:: The main goals of this research are exploration of energy-efficient building materials when replacing natural materials with industrial waste and development of the theory and practice of obtaining light and ultra-light gravel materials based on mineral binders and waste dump ash and slag mixtures of hydraulic removal. Background.: Experimental data on the conditions of formation of gravel materials containing hollow aluminum and silica microsphere with opportunity of receipt of optimum structure and properties depending on humidity with the using of various binders are presented in this article. This article dwells on the scientific study of opportunity physical-mechanical properties of composite materials optimization are considered. Objective.: Composite material contains hollow aluminum and silica microsphere. Method.: The study is based on the application of the method of separation of power and heat engineering functions. The method is based on the use of the factor structure optimality, which takes into account the primary and secondary stress fields of the structural gravel material. This indicates the possibility of obtaining gravel material with the most uniform distribution of nano - and microparticles in the gravel material and the formation of stable matrices with minimization of stress concentrations. Experiments show that the thickness of the cement shell, which performs power functions, is directly related to the size of the raw granules. At the same time, the thickness of the cement crust, regardless of the type of binder, with increasing moisture content has a higher rate of formation for granules of larger diameter. Results.: The conditions for the formation of gravel composite materials containing a hollow aluminosilicate microsphere are studied. The optimal structure and properties of the gravel composite material were obtained. The dependence of the strength function on humidity and the type of binder has been investigated. The optimal size and shape of binary form of gravel material containing a hollow aluminosilicate microsphere with a minimum thickness of a cement shell and a maximum strength function was obtained. Conclusion.: Received structure allows to separate power and heat engineering functions in material and to minimize the content of the excited environment centers.

scholarly journals A General Temperature-Dependent Stress–Strain Constitutive Model for Polymer-Bonded Composite Materials

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1393
Author(s):  
Xiaochang Duan ◽  
Hongwei Yuan ◽  
Wei Tang ◽  
Jingjing He ◽  
Xuefei Guan
Keyword(s):  
Composite Materials ◽  
Constitutive Model ◽  
Model Parameters ◽  
Temperature Dependent ◽  
Stress Strain ◽  
Proposed Model ◽  
Single Temperature ◽  
Testing Data ◽  
Bonded Composite ◽  
Tension And Compression

This study develops a general temperature-dependent stress–strain constitutive model for polymer-bonded composite materials, allowing for the prediction of deformation behaviors under tension and compression in the testing temperature range. Laboratory testing of the material specimens in uniaxial tension and compression at multiple temperatures ranging from −40 ∘C to 75 ∘C is performed. The testing data reveal that the stress–strain response can be divided into two general regimes, namely, a short elastic part followed by the plastic part; therefore, the Ramberg–Osgood relationship is proposed to build the stress–strain constitutive model at a single temperature. By correlating the model parameters with the corresponding temperature using a response surface, a general temperature-dependent stress–strain constitutive model is established. The effectiveness and accuracy of the proposed model are validated using several independent sets of testing data and third-party data. The performance of the proposed model is compared with an existing reference model. The validation and comparison results show that the proposed model has a lower number of parameters and yields smaller relative errors. The proposed constitutive model is further implemented as a user material routine in a finite element package. A simple structural example using the developed user material is presented and its accuracy is verified.

Hierarchical ZSM-22/PHTS composite material and its hydro-isomerization performance in hydro-upgrading of gasoline

2021 ◽  
Author(s):  
Jiyuan Fan ◽  
Chengkun Xiao ◽  
Jinlin Mei ◽  
Cong Liu ◽  
Aijun Duan ◽  
...  
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Impregnation Method ◽  
Molar Ratios

CoMo series catalysts based on ZSM-22/PHTS (ZP) composite materials with different SiO2/Al2O3 molar ratios were prepared via the impregnation method. The properties of the ZP material and the corresponding catalysts...

scholarly journals Acoustic Emission and K-S Metric Entropy as Methods for Determining Mechanical Properties of Composite Materials

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 145
Author(s):  
Lesław Kyzioł ◽  
Katarzyna Panasiuk ◽  
Grzegorz Hajdukiewicz ◽  
Krzysztof Dudzik
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Composite Material ◽  
Composite Materials ◽  
Testing Machine ◽  
Measurement Data ◽  
Entropy Method ◽  
Displacement Sensor ◽  
Metric Entropy ◽  
Plastic Phase

Due to the unique properties of polymer composites, these materials are used in many industries, including shipbuilding (hulls of boats, yachts, motorboats, cutters, ship and cooling doors, pontoons and floats, torpedo tubes and missiles, protective shields, antenna masts, radar shields, and antennas, etc.). Modern measurement methods and tools allow to determine the properties of the composite material, already during its design. The article presents the use of the method of acoustic emission and Kolmogorov-Sinai (K-S) metric entropy to determine the mechanical properties of composites. The tested materials were polyester-glass laminate without additives and with a 10% content of polyester-glass waste. The changes taking place in the composite material during loading were visualized using a piezoelectric sensor used in the acoustic emission method. Thanks to the analysis of the RMS parameter (root mean square of the acoustic emission signal), it is possible to determine the range of stresses at which significant changes occur in the material in terms of its use as a construction material. In the K-S entropy method, an important measuring tool is the extensometer, namely the displacement sensor built into it. The results obtained during the static tensile test with the use of an extensometer allow them to be used to calculate the K-S metric entropy. Many materials, including composite materials, do not have a yield point. In principle, there are no methods for determining the transition of a material from elastic to plastic phase. The authors showed that, with the use of a modern testing machine and very high-quality instrumentation to record measurement data using the Kolmogorov-Sinai (K-S) metric entropy method and the acoustic emission (AE) method, it is possible to determine the material transition from elastic to plastic phase. Determining the yield strength of composite materials is extremely important information when designing a structure.

scholarly journals Development of Detailed FE Numerical Models for Assessing the Replacement of Metal with Composite Materials Applied to an Executive Aircraft Wing

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 178
Author(s):  
Valerio Acanfora ◽  
Roberto Petillo ◽  
Salvatore Incognito ◽  
Gerardo Mario Mirra ◽  
Aniello Riccio
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Numerical Model ◽  
Numerical Models ◽  
Structural Performance ◽  
Aircraft Wing ◽  
Resin Infusion ◽  
Effectiveness Analysis ◽  
Liquid Resin Infusion ◽  
Process Constraints

This work provides a feasibility and effectiveness analysis, through numerical investigation, of metal replacement of primary components with composite material for an executive aircraft wing. In particular, benefits and disadvantages of replacing metal, usually adopted to manufacture this structural component, with composite material are explored. To accomplish this task, a detailed FEM numerical model of the composite aircraft wing was deployed by taking into account process constraints related to Liquid Resin Infusion, which was selected as the preferred manufacturing technique to fabricate the wing. We obtained a geometric and material layup definition for the CFRP components of the wing, which demonstrated that the replacement of the metal elements with composite materials did not affect the structural performance and can guarantee a substantial advantage for the structure in terms of weight reduction when compared to the equivalent metallic configuration, even for existing executive wing configurations.

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