scholarly journals ANALYSIS OF STRENGTH CRITERIA IN THE DESIGN OF PRODUCTS FROM COMPOSITE MATERIALS

2021 ◽  
pp. 46-51
Author(s):  
Andrzej Dzierwa ◽  
Nataliia Stelmach
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Optimal Design ◽  
Composite Structures ◽  
Single Layer ◽  
Unidirectional Composite ◽  
Strength Criteria ◽  
Optimal Criterion ◽  
Allowable Load ◽  
Unidirectional Composite Material

Technological progress gives rise to the continuous expansion of the class of structural materials and the improvement of their properties. The appearance of new materials is due to the natural desire to increase the efficiency of the structures under development. One of the most striking manifestations of progress in the development of materials, structures and technology is associated with the development and application of composite materials. Composites have a number of obvious advantages over other materials, in particular over metals. Such advantages are high specific strength and rigidity, high corrosion resistance, good ability to withstand alternating loads and others. It should be noted another, perhaps the most important feature of composites - is the ability to change the properties of the material in accordance with the purpose of the structure and the nature of its load during operation. Under the influence of loads on the structure, its strength is estimated by the ultimate state of the materials of the structural elements. When a boundary state arises in a material, its transition to another mechanical state - elastic, plastic, or fracture state - occurs. This article aims to determine the optimal criterion for the strength of composite material that takes into account different values of ultimate stresses not only in different directions of the coordinate axes, but also to stretch and compress and further calculate the maximum allowable load for single-layer unidirectional composite material During the research the main properties of composite materials, methods of manufacturing parts from composite material, their main properties and methods of destruction were considered. The characteristics of the strength criteria of composite materials are given, the most suitable for calculating the maximum value of the allowable load for a single-layer unidirectional composite material is determined. The proposed approach to the optimal design of elements of single-layer composite structures may be of interest to developers of numerous and analytical methods for solving problems of optimal design of more complex structures.  

scholarly journals FORECASTING CHARACTERISTICS OF COMPOSITE STRENGTH ON THE BASIS OF PREFORMS IN ELEMENTS OF BUILDING STRUCTURES

2020 ◽  
Vol 6 (159) ◽  
pp. 2-9
Author(s):  
A. Kondratiev ◽  
O. Andrieiev
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Composite Structures ◽  
High Speed ◽  
Mechanical Characteristics ◽  
Unidirectional Composite ◽  
Test Material ◽  
Practical Implementation ◽  
Building Structures ◽  
Physical And Mechanical Characteristics

Currently, wicker composite structures for various purposes are widely used in many industries. The use of such preforms allows to provide the possibility of automation of production, high speed and efficiency of the process of manufacturing polymeric composite materials and structures based on them. Knowledge of their properties allows you to optimize the production of structures with the necessary parameters during design. In the article the model of composite material on the basis of wicker reinforcement was further developed. For the practical implementation of this model, it is sufficient to test material samples with three different angles between the harnesses, for example, ± 30º, ± 45º and ± 60º. A mathematical description of the model is given. The model made it possible to predict the physical and mechanical characteristics of the composite material when it is laid out on curved surfaces. At the same time some fictitious limits of durability of a composite are defined. This is due to the fact that each value of the angle between the harnesses corresponds to its physical and mechanical characteristics of the unidirectional composite material. In this case, the ultimate strength curves necessarily pass through the points corresponding to the experimental data. The article shows that the possible deviations of the strength limits in the range of angles between the harnesses will lie within the range of characteristics obtained by testing. The article shows that in the realized interval of angles between the harnesses, almost any polynomial criterion of strength will accurately describe the strength of the composite reinforced with a braided sleeve. The obtained parameters, in contrast to the existing ones, allow to predict the strength characteristics of the composite on the basis of braided sleeves depending on the positioning and location of the material on the forming surface. The obtained results are the basis for solving the problems of calculating the strength of building structures from composite materials based on wicker preforms.

Damage detection of unidirectional carbon fiber–reinforced laminates with embedded magnetostrictive particulates: A preliminary study

2012 ◽  
Vol 24 (8) ◽  
pp. 991-1006 ◽  
Author(s):  
Oliver J Myers ◽  
George Currie ◽  
Jonathan Rudd ◽  
Dustin Spayde ◽  
Nydeia Wright Bolden
Keyword(s):  
Composite Materials ◽  
Carbon Fiber ◽  
Nondestructive Evaluation ◽  
Composite Laminates ◽  
Composite Structures ◽  
Single Layer ◽  
Polymeric Composite ◽  
Analytical Models ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced

Defects in composite laminates are difficult to detect because of the conductive and paramagnetic properties of composite materials. Timely detection of defects in composite laminates can improve reliability. This research illustrates the preliminary analysis and detection of delaminations in carbon fiber laminate beams using a single layer of magnetostrictive particles and noncontacting concentric magnetic excitation and sensing coils. The baseline analytical models also begin to address the intrusive nature of the magnetostrictive particles as well as relate the applied excitation field with the stress and magnetic flux densities induced in the magnetostrictive layer. Numerical methods are used to begin to characterize the presence of magnetostrictive particles in the laminate and the behavior of the magnetostrictive particles in relationship to the magnetic field used during sensing. Unidirectional laminates with embedded delaminations are used for simulations and experimentations. A novel, yet simplified fabrication method is discussed to ensure consistent scanning and sensing capabilities. The nondestructive evaluation scanning experiments were conducted with various shapes and sizes of damages introduced into carbon fiber–reinforced polymeric composite structures. The results demonstrate high potential for magnetostrictive particles as a low-cost, noncontacting, and reliable sensor for nondestructive evaluation of composite materials.

Damage in Composite Material: A Microwave Detection

2014 ◽  
Vol 605 ◽  
pp. 303-305
Author(s):  
Jerome Rossignol ◽  
Alain Thionnet
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Dielectric Material ◽  
Low Cost ◽  
Unidirectional Composite ◽  
Microstrip Resonator ◽  
Microwave Frequencies ◽  
Fibre Break ◽  
Materials Used ◽  
Non Destructive

In the field of the transport, the increase of the security rule recommends to a periodic control of the structure to detect damage due to mechanical loadings. Now, current materials, used in the case of transport applications, are the composite materials. The methods, to control these materials or composite structures, need to be low cost, non-destructive, in-situ and swiftness as far as possible. The scientific literature reports many methods to control the damage in composite materials and structures. However the above requirements and the adaptation to composite materials reduce the number of methods that can be used. Currently, the adapted methods are based on infrared thermography, acoustical emission, EMIR (ElectroMagnetic InfraRed) or microwave imagery. We present an innovative non-destructive method of detecting damages in composite materials. The method is based on the observation and analysis of the modification in dielectric material resulting from damage. The originality of this method is that the diagnostic is obtained by using a microstrip resonator at microwave frequencies. The feasibility of the method is demonstrated by the detection of a fibre break into an unidirectional composite submitted to a flexural loading. The fibre break is the damage to detect. The perspective of this work is to develop a quantification and a localization of damages.

scholarly journals Optimal Design of Plated/Shell Structures under Flutter Constraints—A Literature Review

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4215 ◽  
Author(s):  
Aleksander Muc ◽  
Justyna Flis ◽  
Marcin Augustyn
Keyword(s):  
Composite Materials ◽  
Optimal Design ◽  
Composite Structures ◽  
Optimization Problems ◽  
Piezoelectric Actuators ◽  
Functionally Graded ◽  
Shell Structures ◽  
Objective Functions ◽  
Graded Materials ◽  
Definition Of

Aeroelastic optimization has become an indispensable component in the evaluation of divergence and flutter characteristics for plated/shell structures. The present paper intends to review the fundamental trends and dominant approaches in the optimal design of engineering constructions. A special attention is focused on the formulation of objective functions/functional and the definition of physical (material) variables, particularly in view of composite materials understood in the broader sense as not only multilayered laminates but also as sandwich structures, nanocomposites, functionally graded materials, and materials with piezoelectric actuators/sensors. Moreover, various original aspects of optimization problems of composite structures are demonstrated, discussed, and reviewed in depth.

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