scholarly journals Crack resistance of masonry walls

2021 ◽  
Vol 31 (4) ◽  
pp. 43-50
Author(s):  
M. K. Ishchuk ◽  
K. A. Aizyatullin
Keyword(s):  
Crack Resistance ◽  
Creep Deformation ◽  
Field Data ◽  
Strain State ◽  
Computer Models ◽  
Masonry Walls ◽  
Design Calculation ◽  
Masonry Buildings ◽  
Stress Strain ◽  
Stress Strain State

Computer models used in the design calculation of masonry buildings sometimes fail to correctly take into account the stress-strain state of walls and assess the likelihood of cracks caused by the deformation differences of interacting walls.Following the construction of a building, cracks can develop at wall intersections for several years. However, their repair is mostly ineffective until the total damping of masonry creep deformation.Drawing on the analysis of conducted research and field data, the authors give recommendations on ensuring the crack resistance of internal masonry walls.

scholarly journals Critical stresses arising in the destruction of a floating reinforced concrete pontoon

2021 ◽  
Vol 264 ◽  
pp. 03032
Author(s):  
Dina Morozova ◽  
Dmitrii Malakhov
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Strain State ◽  
Wind Wave ◽  
Computer Models ◽  
Stress Strain ◽  
Stress Strain State ◽  
Critical Stresses ◽  
Extreme Wind ◽  
Wave Effects

The article discusses the stress-strain state of a reinforced concrete floating pontoon caused by critical stresses before its destruction. The investigation was motivated by the destruction of the pontoon, which occurred under extreme wind and wave impacts. A method for determining wind, wave and current loads is presented. The investigation was carried out on finite element computer models. As a result of the investigation, critical efforts and stresses were obtained, causing the destruction of the pontoon. The main conclusion of the conducted investigation is the possibility of using a floating reinforced concrete pontoon in waters with limited values of wind, wave effects and loads from the current.

scholarly journals THE STRENGTH OF REINFORCED CONCRETE BEAM ELEMENTS UNDER CYCLIC ALTERNATING LOADING AND LOW CYCLE LOAD OF CONSTANT SIGN

Vestnik MGSU ◽  
2015 ◽  
pp. 36-50 ◽  
Author(s):  
Yuliya Anatol'evna Semina
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Strain State ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Constant Sign ◽  
Stress Strain ◽  
Beam Elements ◽  
Stress Strain State ◽  
The Impact

The behavior of reinforced concrete elements under some types of cyclic loads is described in the paper. The main aim of the investigations is research of the stress-strain state and strength of the inclined sections of reinforced concrete beam elements in conditions of systemic impact of constructive factors and the factor of external influence. To spotlight the problem of cyclic loadings three series of tests were conducted by the author. Firstly, the analysis of the tests showed that especially cyclic alternating loading reduces the bearing capacity of reinforced concrete beams and their crack resistance by 20 % due to the fatigue of concrete and reinforcement. Thus the change of load sign creates serious changes of stress-strain state of reinforced concrete beam elements. Low cycle loads of constant sign effect the behavior of the constructions not so adversely. Secondly, based on the experimental data mathematical models of elements’ strength were obtained. These models allow evaluating the impact of each factor on the output parameter not only separately, but also in interaction with each other. Furthermore, the material spotlighted by the author describes stress-strain state of the investigated elements, cracking mechanism, changes of deflection values, the influence of mode cyclic loading during the tests. Since the data on the subject are useful and important to building practice, the ultimate aim of the tests will be working out for improvement of nonlinear calculation models of span reinforced concrete constructions taking into account the impact of these loads, and also there will be the development of engineering calculation techniques of their strength, crack resistance and deformability.

scholarly journals The impact of the reinforcement percentage on the stress-strain state of the bending steel fiber reinforced concrete elements

2018 ◽  
Vol 230 ◽  
pp. 02001 ◽  
Author(s):  
Oleksandr Andriichuk ◽  
Volodymyr Babich ◽  
Ivan Yasyuk ◽  
Serhii Uzhehov
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Cross Section ◽  
Strain State ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Steel Fiber Reinforced Concrete ◽  
Stress Strain ◽  
Stress Strain State ◽  
Reinforcement Percentage

The use of concrete with traditional reinforcement pose the problem of finding ways to increase the crack resistance, impact strength, frost resistance and other characteristics, which in turn depend on the strength properties of the material. One of the solution is the use of dispersion reinforced concrete steel fiber concrete (with short steel fibers of 30-50mm). The combination of rigid fibers with significant strength reserves and the concrete could increase the crack resistance of the matrix and other strength characteristics. The paper presents the results of theoretical studies of the reinforcement percentage effect on the stress-strain state of the rectangular cross-section elements of steel fiber reinforced concrete (SFRC) in bending from at repeated loads with levels of application η = 0.5 and η = 0.7 . It is found that the limit deformations of the SFRC cross-section in bending is recommended to calculate using a polynomial function, which gives the greatest convergence between the true values and approximations in comparison with the logarithmic and exponential functions.

Assessment of the Stress State of the Coating in Depending on the Porosity of the Cement Substrate

2017 ◽  
Vol 737 ◽  
pp. 179-183 ◽  
Author(s):  
Valentina Ivanovna Loganina ◽  
Jury Skachkov
Keyword(s):  
Stress State ◽  
Crack Resistance ◽  
Internal Stress ◽  
Contact Area ◽  
Coating Thickness ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State ◽  
Technological Methods

It is shown the data on the value of the internal stress in the coating depending on the diameter of the pores of the cement substrate, as well as coating thickness. It is shown the calculated dependences allowing to determine the absence of cracking in the coating. Determined, that the presence of pores in the contact area coating with the cement substrate contributes to a more inhomogeneous stress-strain state in comparison with the smooth, without pores substrate. Shown, that in order to improve the crack resistance must be to seek technological methods to create the cement substrates, characterized by small pores uniformly distributed.

КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ХВОСТО-ВИХ БАЛОК СІТЧАСТОГО ТИПУ З ПОЛІМЕРНИХ КОМПО-ЗИЦІЙНИХ МАТЕРІАЛІВ ВЕРТОЛЬОТІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

2020 ◽  
pp. 15-30
Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Layer Structure ◽  
Metal Structure ◽  
Element Model ◽  
Stress Strain ◽  
Element Analysis ◽  
Mesh Structure ◽  
Stress Strain State ◽  
Mesh Structures

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.

Sign in / Sign up

Export Citation Format

Share Document