scholarly journals Stress state of the foundations of buildings and structures

Author(s):  
E. K. Agakhanov ◽  
S. T. Khidirov ◽  
G. G. Gabibulaev

Objective. Determination of the stress state of a ground base with a trapezoidal cutoff from the action of own weight, according to the conditions of equivalence of effects, is reduced to determining the stress state from the external surface load distributed according to the hydrostatic law. Methods. The problem of determining the stresses in the structure foundations at any degree of areas development of a plastic strain of the soil has a strict mathematical formulation, and similarity criteria can be obtained using a simpler construct of similarity theory. The simulation is performed by using similarity criteria based on which the model is executed, the loading conditions are determined, and the transition from the values measured on the model to the corresponding values of the full-scale structure is carried out. Similarity criteria can be obtained either with the help of similarity theory or with the help of dimensional analysis. An even greater effect of increasing the self-weight of a model made of transparent optically sensitive material can be achieved using the immersion method in conjunction with the centrifugal modeling method. If necessary, the stresses in the model area are fixed using the "freeze" method. Result. Using the equations system of the mixed problem of the elasticity and plasticity theory, and the scale method, similarity criteria are established for modeling stresses in the foundations of buildings and structures. Limitations on the choice of similarity multipliers for loose soils, the possibility of using the method of centrifugal modeling, as well as features of modeling connected soils are noted. Conclusion. A necessary condition for the similarity of the stress states of loose homogeneous bases in nature and the model is the equality of the similarity multipliers of the geometric scale and the force factor. 

2014 ◽  
Vol 611 ◽  
pp. 405-411 ◽  
Author(s):  
Oskar Ostertag ◽  
Eva Ostertagová ◽  
Peter Frankovský

The presented article is dedicated to stress state development while assessing the concentration of stresses in samples with continuously changing notches. These samples represent connecting elements of structural parts. The stress states of selected samples were determined experimentally by means of reflection photoelasticity. This method is suitable mainly for determination of stress state in the whole area in question, predominantly though for the analysis of stress concentration and its gradient in the notched area. Within the method of reflection photoelasticity, a layer was used to analyse the stress field. When loaded, this layer exhibits the ability of temporal birefringence. One of the statistical methods was selected in order to predict the stress state of other samples with bigger notches.


2015 ◽  
Vol 11 (1) ◽  
pp. 29-37
Author(s):  
Giang Nguyen

Abstract The paper deals with the determination of stress induced in spread foundation subsoil by Slovak Technical Standard STN 73 1001:2010 (STN) and Polish Standard PN-81/B-03020 (PN). While STN does not consider with stress state in subsoil just after carrying out excavation and the stress is determined from overloading only, PN considers with stress states after carrying out excavation and follows loading. Differences are also in determination of foundation stiffness and taking into account soil structural strength. It will be shown that different approaches make difference in the value of additional stress up to 18.6 %.


1988 ◽  
Vol 41 (2) ◽  
pp. 189 ◽  
Author(s):  
RA Winholtz ◽  
JB Cohen

The determination of residual stresses via X-ray diffraction is briefly reviewed, with particular emphasis on the triaxial stress state. A new method is proposed for determining the general stress tensor, which considerably reduces the variances of the stresses due to counting statistics and gradients. The procedure involves a generalised least-squares solution of strains measured at various tilts of the X-ray beam to the sample, and a new set of tilts is recommended to minimise these errors.


2021 ◽  
Vol 27 (1) ◽  
pp. 33-39
Author(s):  
Dragan Petrović ◽  
Milan Bižić

The task of this paper is determining the zone of influence of a circular hole on the stress state of a homogeneous isotropic plate in pure bending condition. For solving the problem, the complex variable method was used which allows the complete analytical determination of the stresses at every point of the plate, and particularly on the contour of the circular hole. The analytical expressions for stresses in the plate of infinite dimensions were the basis for deriving a mathematical formulation which defines the zone as a function of diameter of the hole, inside which there is influence of the hole on the stress state of the plate. Obtained results are verified with FEM using the ANSYS software package whereby the input data for spatial discretization and mesh generation are not previously adjusted but was used a mesh that is generated automatically by the program.


2015 ◽  
Vol 31 (1) ◽  
pp. 20-30 ◽  
Author(s):  
William S. Helton ◽  
Katharina Näswall

Conscious appraisals of stress, or stress states, are an important aspect of human performance. This article presents evidence supporting the validity and measurement characteristics of a short multidimensional self-report measure of stress state, the Short Stress State Questionnaire (SSSQ; Helton, 2004 ). The SSSQ measures task engagement, distress, and worry. A confirmatory factor analysis of the SSSQ using data pooled from multiple samples suggests the SSSQ does have a three factor structure and post-task changes are not due to changes in factor structure, but to mean level changes (state changes). In addition, the SSSQ demonstrates sensitivity to task stressors in line with hypotheses. Different task conditions elicited unique patterns of stress state on the three factors of the SSSQ in line with prior predictions. The 24-item SSSQ is a valid measure of stress state which may be useful to researchers interested in conscious appraisals of task-related stress.


Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1495
Author(s):  
Dan-Andrei Șerban ◽  
Cosmin Marșavina ◽  
Alexandru Viorel Coșa ◽  
George Belgiu ◽  
Radu Negru

In this article, the yielding and plastic flow of a rapid-prototyped ABS compound was investigated for various plane stress states. The experimental procedures consisted of multiaxial tests performed on an Arcan device on specimens manufactured through photopolymerization. Numerical analyses were employed in order to determine the yield points for each stress state configuration. The results were used for the calibration of the Hosford yield criterion and flow potential. Numerical analyses performed on identical specimen models and test configurations yielded results that are in accordance with the experimental data.


2011 ◽  
Vol 70 ◽  
pp. 225-230 ◽  
Author(s):  
Agnieszka Derewonko ◽  
Andrzej Kiczko

The purpose of this paper is to describe the selection process of a rubber-like material model useful for simulation behaviour of an inflatable air cushion under multi-axial stress states. The air cushion is a part of a single segment of a pontoon bridge. The air cushion is constructed of a polyester fabric reinforced membrane such as Hypalon®. From a numerical point of view such a composite type poses a challenge since numerical ill-conditioning can occur due to stiffness differences between rubber and fabric. Due to the analysis of the large deformation dynamic response of the structure, the LS-Dyna code is used. Since LS-Dyna contains more than two-hundred constitutive models the inverse method is used to determine parameters characterizing the material on the base of results of the experimental test.


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