Introduction. The results of surveillance of the processes of roads structures under climatic conditions of Ukraine testify that, as a rule, their largest intensity occurs as a consequence of daily and seasons changes of the environmental temperature. As this takes place, at the initial stage, the most noticeable delaminations and destructions are realized in form of transversal cracks in the zones of its free surface. In this publication, the possibility of these destructions initiation under change in time of the temperature perturbations is analyzed taking into account the variation of the stiffness characteristics of the road materials/
Problems. In the last time, throughout the world motorways, the tendency of enlargement of heavy trucks traffic intensity and increase of heavy load multi-axes automobiles and motor trains is realized. Essential influence on the road structures stress-strain states is rendered by the temperature and climate actions stipulated by daily and seasonal changes of the road coverings temperatures. The main property of the thermo-loaded states analysis of the road structures is associated their multiparametericity. First of all, the road overlay is essentially non-homogeneous. In the mechanics of deformable media, the multi-layer heterogeneous systems are separated, which consist of elastic layers with different thermo-mechanical characteristics, and gradiently heterogeneous media are considered with properties continuously changing along spatial variables. Inasmuch as the road overlay can be related as multi-layered heterogeneous systems in mathematic modelling thermo-mechanic processes, it is necessary to take into consideration the specificity of distribution of the fields of temperature, strains and stresses (and sometimes, displacements) are discontinuous and it is difficult to describe them by simple analytic or numerical methods. These peculiarities are the reasons of essential complication of mechanical phenomena occurring in these structures.
Purpose. The mathematic modeling of thermo-elastic loading of the road coating structures.
The research object. The research object is mathematic modelling of thermo-elastic loading phenomena in the road overlay structures. The mathematic models of the phenomena of thermo elastic deforming the layered road coatings with planar and curvilinear surfaces under conditions of daily and seasonally changing temperatures and transport loads are proposed. It is shown through the use of finite element method that the temperature fields caused by the external thermal perturbations have the modes of high gradient boundary effects formed in the boundary zones of the system. For this reason, the generated stress functions are discontinuous and include the concentration zones in different regions of the body. The spots with maximal values of tensile and shear forces, initiating the structure, delamination, are established. The loading situations for different values of geometric, structural and thermal parameters are considered. Some paradoxical effects in the mechanisms of the system destruction are detected.
Conclusions. The problem of the numerical investigation of the layered is stated with allowance made for change and seasonal variations of the environmental temperatures. The constitutive differential equations are formulated, their finite element analogs are constructed. It is established that the stated problem is singularly perturbed at the selected values of the geometric and thermo-mechanic parameters of the road structure and the temperature fields (evolving in time) have the forms of boundary effects in the vicinity of the first and second layers of the road. It is shown that the maximal values of longitudinal tensile stresses in the top layer of the overlay and of shear stresses are localized
between the first and so they can be the main cause of the lateral crack initiation and road destruction in the winter and spring seasons.
Mechanical effects and paradoxical phenomena in the thermoelastic stress of the road pavement structures
published: 2019-07-10
Number: Issue 18(2018)
Section: Construction and civil engineering
The page spacing of the article: 128-145
Keywords: road pavement, road pavement structure, thermoelastic stress, temperature field, stress field.
How to quote an article:
Viktor Mozghovyi, Viktor Gaidaichuk, Yurii Zaiets, Liudmyla Shevchuk. Oleksandr Gustieliev, Oleksandr Kutsman. Mechanical effects and paradoxical phenomena in the thermoelastic stress of the road pavement structures. Dorogi і mosti [Roads and bridges]. Kyiv, 2018. 18. P. 128-145 [in Ukrainian]
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