Calculation of the deformation properties of materials made of chemical fibres

Various composite building products consisting of layers of different physical-mechanical properties being tied rigidly together are manufactured and used in construction. In many cases such products curve, become flaky, crack and their thermo-insulating capability suffers. It occurs because deformation properties are not adjusted, different layers of such products deform differently under the load. And the deformation effects the behaviour of the whole structure. A correct adjustment of deformations can be achieved with allowance for creep of different layers and of the whole composite. Determination of creep parameters—creep coefficient and specific creep—depends on the orientation of layers in respect of the direction of force action. When layers are situated transverselly in respect of the direction of action of forces (stresses), creep parameters of composite depend on creep parameters of materials of separate layers and on relative volumes of these layers. Creep deformations of a composite can be described by equations describing creep of individual layers. Appropriate equations and formulas ((17)-(25)) are presented for determining such deformations. When layers are parallel to the direction of stresses, redistribution of these stresses between layers takes place. Compression stresses increase in a layer with higher modulus of deformation and decrease in that with lower modules. Proposed equations (37)-(42) enable to determine redistribution of stresses between layers, the main creep parameters of composite, their modulus of deformations and creep deformations themselves when strength of a composite product is reached, E(t0)=E(t)=const and stresses produce linear creep. Such loading of a composite product is the most common in practice. Presented formulas ((46), (52)) and diagrams show that it is possible to design a composite building product or material with creep parameters given in advance by means of appropriate distribution of product layers, selecting ratios between layers and properties of materials.

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Non-linear deformation properties of materials with stochastically distributed anisotropic inclusions

PAMM ◽

10.1002/pamm.201310122 ◽

2013 ◽

Vol 13 (1) ◽

pp. 253-254 ◽

Cited By ~ 1

Author(s):

Lidiia Nazarenko ◽

Swantje Bargmann ◽

Leonid Khoroshun

Keyword(s):

Linear Deformation ◽

Deformation Properties ◽

Non Linear ◽

Properties Of Materials

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Strength evaluation of concrete elements with non-metallic reinforcement under short-term dynamic compression

EPJ Web of Conferences ◽

10.1051/epjconf/201922101035 ◽

2019 ◽

Vol 221 ◽

pp. 01035

Author(s):

Vasilii Plevkov ◽

Igor Baldin ◽

Andrei Nevskii

Keyword(s):

Nonlinear Deformation ◽

Dynamic Compression ◽

Deformation Model ◽

Short Term ◽

External Reinforcement ◽

Deformation Properties ◽

Metallic Reinforcement ◽

Properties Of Materials ◽

Concrete Elements ◽

Nonlinear Deformation Model

The article presents a method for calculating the strength of concrete elements with non-metallic fiber, rod and external reinforcement. The algorithm and the calculation program are shown, which are based on the use of a nonlinear deformation model of the normal section of such elements, taking into account the real deformation properties of materials under static and short-term dynamic loading.

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Limit states and safety factors under repeated loading

PNRPU Mechanics Bulletin ◽

10.15593/perm.mech/2020.3.12 ◽

2020 ◽

pp. 125-135

Author(s):

O. F Chernyavsky ◽

A. O Chernyavsky

Keyword(s):

Inelastic Deformation ◽

Low Cycle Fatigue ◽

Qualitative Change ◽

Repeated Loading ◽

Calculation Methods ◽

Safety Factors ◽

Limit States ◽

Load Range ◽

Deformation Properties ◽

Properties Of Materials

Verification of the structures operating possibility using numerical modeling beyond the elastic limit requires standardization of safety factors and calculation methods used to get them. In the framework of the discussion on the improvement of the strength standards of the aviation and nuclear industries for structures operating under low-cycle mechanical and reversible dilatation (temperature, hydrogen) external influences, the article discusses the limiting states; the deformation properties of materials necessary for their calculation; safety factors for loads and durability; calculation methods. The article divides limit states of structures under low-cycle actions into two groups: typical, corresponding to a qualitative change in the deformation type, and individual, determined by allowable displacements and cracks for a particular structure. The following types of deformation are considered: inelastic deformation only at the running-in stage (that changes to elastic after the auspicious residual stresses develop and cyclic hardening of the material); alternating flow (that continues with the number of cycles); progressive accumulation of strains and displacements; combined deformation (when both strain span and strain increment are non-zero in a stable cycle). The types of deformation differ in possible consequences for the structure and the initial data for the calculation: mechanical properties of the material required for modeling different types of deformation should be determined by fundamentally different tests. An analysis of individual limit states without taking into account differences in the types of deformation - and thus typical limit states - may be incorrect. The main focus of the article is on typical limit states. The limit states vary depending on the stage of operation at which inelastic cyclic deformation is allowed. Inelastic deformation expands allowable load range, the expansion due to the inelastic deformation at the running-in stage only is usually more significant than additional expansion due to the continuous inelastic deformation; besides, the inelastic deformation only at the running-in stage does not demand analysis of low-cycle fatigue and accumulated strains. Further expansion of the permissible load range, as well as solution of safety problems based on risk assessments, requires a more complete study of the deformation properties of materials at the pre-fracture stage, where cyclic softening predominates.

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Study of the tensile properties of materials for clothing

Bulletin of Kazakh Leading Academy of Architecture and Construction ◽

10.51488/1680-080x/2020.3-38 ◽

2020 ◽

Vol 77 (3) ◽

pp. 280-286

Keyword(s):

Tensile Properties ◽

Experimental Studies ◽

Deformation Properties ◽

Properties Of Materials ◽

Materials Used ◽

Residual Deformations

The article is devoted to the study of the nature and magnitude of deformations in the materials used in the details of shoulder clothing. Experimental studies were performed under the double-walled impact of a tangential deformable load to determine the values f residual deformations. As a result of experimental studies of the deformation properties of samples of coat fabrics, the values of residual deformations are obtained for various load cases. The results of experimental studies are recommended for use in the appointment of constructive increases.

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EFFECT OF DOSAGE OF REDISPUTABLE POWDERS AND THE TYPE OF LOW-MODULAR INCLUSIONS ON THE PROPERTIES OF FINE-AGGREGATE CONCRETE

Herald of Dagestan State Technical University Technical Sciences ◽

10.21822/2073-6185-2019-46-2-167-175 ◽

2019 ◽

Vol 46 (2) ◽

pp. 167-175 ◽

Cited By ~ 1

Author(s):

A. V. Dolgova ◽

G. V. Nesvetaev

Keyword(s):

Fine Aggregate ◽

Fine Grained ◽

Deformation Properties ◽

Low Modulus ◽

Strength And Deformation ◽

Properties Of Materials ◽

Materials Used ◽

Entrained Air ◽

Polymer Powders

Objectives Reliability and durability of structures using materials with various properties (plaster coatings, cement glue, new concrete during repair and restoration of structures, etc.) largely depends on the adhesion of the layers and the deformation properties of the coatings. To obtain the required properties of materials used for coatings, modifiers based on polymers and low-modulus inclusions are introduced into the composition of new concretes, for example, entrained air. The aim of the work is to identify some patterns of change in the properties of concrete with the joint introduction of these modifiers.Method Experimental determination of the tensile strength in bending, compression, E-modulus, adhesion to the concrete base by standard methods.Result The influence of separate and joint introduction of dispersible polymer powders and various low-modulus inclusions into the composition of fine-grained concrete has been established.Conclusion The joint introduction to the composition of fine-grained concrete of various low-modulus inclusions and redispersible polymer powders provides a reduction in the stress level during forced deformations due to the different effects additives on the strength and deformation properties and contributes to increased adhesion to the concrete.

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Experimental Investigation of Large Deformation Fracture for Rubber Materials

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.417-418.613 ◽

2009 ◽

Vol 417-418 ◽

pp. 613-616

Author(s):

Yi Lan Kang ◽

X. Xiao ◽

Xiao Lei Li ◽

Xiao Hua Tan

Keyword(s):

Large Deformation ◽

Crack Tip ◽

Mixed Mode Fracture ◽

Crack Tip Field ◽

Engineering Structures ◽

Shear Component ◽

Deformation Properties ◽

Properties Of Materials ◽

Digital Moiré ◽

Displacement Information

With the increasing investigation on reliability and stability of engineering structures, it becomes important for reseach on mechanical properties of materials under fracutre conditions. Concerning to fracture problems of large deformation materials, deformation characteristics of the crack tip field is necessarily needed. This paper presents an experimental analysis on a double-cracked rubber disk under the I-II mixed-mode fracture condition. Deformation properties around the crack tip are described through analyzing displacement information acquired by digital moiré method of circular and radial gratings. Also the existence of sector division mode under mixed loading condition is verified, and it is also found experimentally that the shear component makes the sectors shift.

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THE DEVELOPMENT OF METHODS FOR RAPID PREDICTION OF FROST RESISTANCE OF CERAMIC PRODUCTS/KERAMINIŲ GAMINIŲ ATSPARUMO ŠALČIUI SPARČIŲJŲ PROGNOZAVIMO METODŲ RAIDA

Journal of Civil Engineering and Management ◽

10.3846/13921525.1999.10531466 ◽

1999 ◽

Vol 5 (3) ◽

pp. 222-228

Author(s):

Asta Kičaitė

Keyword(s):

Frost Resistance ◽

Ceramic Body ◽

Prediction Methods ◽

Construction Sites ◽

Rapid Methods ◽

Deformation Properties ◽

Rapid Prediction ◽

Destructive Action ◽

Properties Of Materials

One of important parameters determining the quality of ceramic products is the resistance to frost. Frost resistance of ceramic brick can be determined exactly by direct unilateral freezing methods. Investigations by these methods last from some days to several months. Therefore rapid prediction methods become more important. Rapid methods for predicting frost resistance of ceramic products give more detailed data if chosen properties of materials that reflect better destructive action of water during freezing in a ceramic body are more exact. Nowadays the methods for rapid prediction are divided according to the quantity of parameters used for prediction and according to the established characteristics. The prediction of frost resistance of ceramic products can be carried out using a parameter or some parameters. The prediction methods using some parameters are divided into three groups: the prediction of frost resistance of ceramic products according to the size of pores and their distribution; the prediction for frost resistance of ceramic products according to physical, mechanical and structural properties; the prediction for frost resistance of ceramic products according to structural and deformation properties. The analysis leads to the following conclusions: - for prediction of frost resistance of ceramic products during the service life, it is necessary to use methods based on unilateral freezing; - rapid methods of prediction based on usage of more parameters are much more reliable and better correspond to frost resistance of ceramic products; - rapid methods of prediction allow to determine quickly frost resistance and to stop the delivery of poor products to construction sites; - dilatometric methods are more comfortable and therefore more prospective.

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Metallurgical Effects of Grain Boundary Ledges

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078225 ◽

1977 ◽

Vol 35 ◽

pp. 126-129

Author(s):

L.E. Murr

Keyword(s):

Grain Boundary ◽

Quantitative Data ◽

Mechanical Treatment ◽

Unit Length ◽

Physical And Mechanical Properties ◽

Direct Observations ◽

Transmission Electron ◽

Properties Of Materials ◽

Thermo Mechanical Treatment ◽

Ledge Density

Ledges in grain boundaries can be identified by their characteristic contrast features (straight, black-white lines) distinct from those of lattice dislocations, for example1,2 [see Fig. 1(a) and (b)]. Simple contrast rules as pointed out by Murr and Venkatesh2, can be established so that ledges may be recognized with come confidence, and the number of ledges per unit length of grain boundary (referred to as the ledge density, m) measured by direct observations in the transmission electron microscope. Such measurements can then give rise to quantitative data which can be used to provide evidence for the influence of ledges on the physical and mechanical properties of materials.It has been shown that ledge density can be systematically altered in some metals by thermo-mechanical treatment3,4.

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