CALCULATION OF BENDING ELEMENTS OF WOOD AFTER THE ACTION OF LOW-CYCLE REPEATED LOADS ON THE CRITERION OF DEFORMATION DESTRUCTION

Author(s):  
E M Babich ◽  
S S Gomon

Existing norms of design for wooden constructions valid in different countries including Ukraine entirely disregard the effect of low-cycle repeated loadings during the operation of buildings and structures. The article deals with development of the bearing capacity computation of the bending elements manufactured from solid and glue-laminated wood exposed to repeated loadings in accordance with the deformation model.Equilibrium equations for computing the bending element made of wood after being exposed to repeated loadings are presented in the article. The deformation method is proposed for the computation of the rectangular wooden beams manufactured from solid and glued laminated wood with allowance for the occurrence of folds in the compression zone.The results of the research allow designing the solid and glue-laminated wooden constructions taking into consideration the possibilities of the material and peculiar features of the performance of the element, which in turn will allow choosing the cross-section of the elements of building structures more economically.On the basis of the study of the process of layer deformation by section height and the determination of the characteristics of the stress-strain state of these layers under the effect of repeated loading, it is possible to fulfill more accurate computation of the elements manufactured from wood at different stages of the stress-strain state through destruction.

2018 ◽  
Vol 196 ◽  
pp. 02003 ◽  
Author(s):  
Alexey Beskopylny ◽  
Elena Kadomtseva ◽  
Grigory Strelnikov

The work considers a reinforced concrete beam made of bimodule material on an elastic Winkler base. The influence of the number of reinforcing bars located in the stretched zone on the maximum normal stress and the maximum deflection is numerically investigated. The choice of the cross-section dimensions, such as the width and thickness of the flanges, the height of the beam, causes particular difficulties and is limited by the need to determine specific ratios of I-beam sizes. Numerical investigation allows analyzing the influence of the width of the I-beam flange that is in contact with the elastic base on the maximum tensile stresses and maximum deflection. The effect on the stressed-deformed state of the various cross-section forms is carried out in work for an I-beam, a rectangle, and a T-beam. Related to the fact that for many building materials the elastic moduli for tension and compression differ, it became necessary to determine the influence of material heterogeneity on the stress-strain state of the elements of building structures. In particular, the widespread use of reinforced concrete beams as elements of band foundations requires a refinement of the stress-strain state study taking into account the heterogeneity of concrete.


2014 ◽  
Vol 13 (3) ◽  
pp. 065-070
Author(s):  
Zinoviy Blikharskyy ◽  
Dmytro Dubizhanskyy ◽  
Roman Khmil

Bearing capacity of normal cross section of bending concrete elements reinforced with reinforced concrete ring under load was investigated. Experimental researches of 4 sets of beams with the total number of 16 units were carried out. The results of changes of stress-strain state settings depending on the load level, additional reinforcement, influence of limit level load were analyzed. The three characteristic stages of stress-strain state of reinforced concrete beams strengthened with reinforced concrete ring were defined. Results of experimental investigations of bearing capacity of normal cross section of strengthened beams with reinforced concrete ring under load were presented. Enhancing effect was calculated. According to the results of researches of strengthened beams plots of strain of working armature depending on current bending moment were constructed.


2020 ◽  
Vol 60 (4) ◽  
pp. 324-337
Author(s):  
Oksana Lytvyniak

This article presents a theoretical study of a stress-strain state of layered reinforced concrete - foam concrete floor slabs (hereinafter called as the LRFCS), with the use of a deformation analysis. Compressive and tensile diagrams of the foam concrete, a tensile diagram of the reinforced concrete and compressive and tensile diagrams of the reinforcement rod are used for the estimation of the stress-strain state of the calculated cross-section of the LRFCS. It should be noted that this article presents the deformation method of loading by the scheme of pure bending for the LRFCS. This deformation method of loading is determined by six shapes of the stress-strain state. These shapes of the stress-strain state are represented by the corresponding distribution diagrams of the relative deformations and the distribution diagrams of internal stresses in the calculated cross-section of the floor slab. Also, this article presents the corresponding equilibrium equations of internal efforts and moments, which act in the calculated cross-section of the floor slab for all shapes of its stress-strain state. Consequently, the mentioned recommendations and mathematical dependencies allow to evaluate the stress-strain state of the LRFCS from its initial loading to its destruction.


Author(s):  
I Belmas ◽  
D Kolosov ◽  
O Dolgov ◽  
H Tantsura ◽  
S Onyshchenko

Purpose. Development and justification of a method of analytical determination of a stress-strain state of a flat rubber-cable tractive-transporting element with breakages of continuity of cable groups in different cross-sections. Methodology of research is in development of a mathematical model of interaction of tractive-transporting element parts considering breakages of groups of random cables, construction of analytical solutions for determining dependencies of force distribution between cables and shear stresses in an elastic shell of a tractive-transporting element with random locations of breakages of cable groups in different cross-sections. Findings. A model of a flat rubber-cable tractive-transporting element with random locations of breakages of cable groups in different cross-sections is developed. Expressions that allow determining a stress-strain state of a flat rubber-cable tractive-transporting element of a hoisting and transporting machine with random locations of breakages of cable groups in different cross-sections are obtained analytically in a closed form. Strength conditions are formulated. Scientific novelty is in establishment of dependencies of interaction of disturbance fields of a stress-strain state of a rubber-cable tractive-transporting element with breakages of continuity of random cable groups in different cross-sections. It is established that disturbance fields caused by breakages of adjacent cables overlap when the breakages are located in one cross-section and there are less than three whole cables located between the broken cables. Disturbance fields also overlap when the same cable or the adjacent cable is broken in both cross-sections and the distance between cross-sections of breakage does not exceed the value, which depends on the design of a flat rubber-cable tractive-transporting element and mechanical properties of its components. Practical significance. The obtained algorithms and strength conditions allow determining a stress-strain state and preventing the breakage of the entire flat rubber-cable tractive-transporting element with breakages of cable groups in different cross-sections. These cross-sections can be: cross-section of the edge of a butt joint, where cables have breakages of continuity; cross-section, which includes the edge of an area of partial restoration of a tractive ability of the element, lost due to breakage of a cable; cross-section of cable or cable group breakage during operation. A possibility of establishing a stress-strain state and the strength conditions of a tractive-transporting element under such conditions allows reasonable determination of a possibility of its further operation in a hoisting and transporting machine.


Author(s):  
Vadym Govorov ◽  
Naryman Sultanov ◽  
Maksim Chusovytyn

Objective: To develop a universal method of track structure elements’ strength analysis, taking into account variable cross-section of elements and the form of foundation. To provide a graph-analytical model of analysis, as the basis of the method, for calculating stress-strain state characteristics of a beam on elastic foundation. Methods: Graph-analytical method was used to identify the characteristics of stress-strain state of a beam on elastic foundation. The method in question is an alternative one, compared to a routine theoretical calculation, the basis of which is a fundamental equation of a bending line and further from this equation, by means of successive integration method, any characteristic of stress-strain state of a beam on elastic foundation can be obtained. Results: A universal graph-analytical method was developed, taking into account factors, which cause deviation from a theoretical scheme of a beam bearing on elastic foundation, such as the possibility of calculating different elements of track structure bearing capacity, considering its variable cross-section (sole chairs, ferroconcrete sleepers, tongues, frogs, etc.), foundation form alternation, on which the calculated elements bear, as well as unequal elasticity of foundation. Practical importance: Application of such a universal method, which differs from an accepted idealized scheme of a beam bearing on elastic foundation, offers wide perspectives in stress-strain state assessment of not only new tracks, being designed, but also in the process of their current state. Application of the method in question makes it possible to avoid analytical lengthy mathematical calculations with any form of cross-section alternation along the length of a beam, with any form of foundation, as well as heavy expenditures, compared to other modern bearing capacity calculating methods, such as finite element method, finite difference method, and finite volume method.


2016 ◽  
Vol 86 ◽  
pp. 02019 ◽  
Author(s):  
Anastasia Chulkova ◽  
Sergey Lukichev ◽  
Marina Romanovich

1999 ◽  
Vol 97 (1) ◽  
pp. 3826-3829
Author(s):  
Ya. M. Grigorenko ◽  
A. T. Vasilenko

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