Termination of Process of Finite Plastic Deformations in Disks under Combined Loadings

1992 ◽  
pp. 547-556
Author(s):  
M. Życzkowski ◽  
K. Szuwalski ◽  
B. Skoczeń
Keyword(s):  
Plastic Deformations ◽  
Combined Loadings

Masonry: the brittle or plastic material?

2019 ◽  
pp. 22-28
Keyword(s):  
Plastic Material ◽  
Experimental Studies ◽  
Point Of View ◽  
Plastic Properties ◽  
Plastic Deformations ◽  
Base Materials ◽  
Stress States ◽  
Creep Deformations ◽  
Structural Point

The results of experimental studies of masonry on the action of dynamic and static (short-term and long-term) loads are presented. The possibility of plastic deformations in the masonry is analyzed for different types of force effects. The falsity of the proposed approach to the estimation of the coefficient of plasticity of masonry, taking into account the ratio of elastic and total deformations of the masonry is noted. The study of the works of Soviet scientists revealed that the masonry under the action of seismic loads refers to brittle materials in the complete absence of plastic properties in it in the process of instantaneous application of forces. For the cases of uniaxial and plane stress states of the masonry, data on the coefficient of plasticity obtained from the experiment are presented. On the basis of experimental studies the influence of the strength of the so-called base materials (brick, mortar) on the bearing capacity of the masonry, regardless of the nature of the application of forces and the type of its stress state, is noted. The analysis of works of prof. S. V. Polyakov makes it possible to draw a conclusion that at the long application of the load, characteristic for the masonry are not plastic deformations, but creep deformations. It is shown that the proposals of some authors on the need to reduce the level of adhesion of the mortar to the brick for the masonry erected in earthquake-prone regions in order to improve its plastic properties are erroneous both from the structural point of view and from the point of view of ensuring the seismic resistance of structures. It is noted that the proposal to assess the plasticity of the masonry of ceramic brick walls and large-format ceramic stone with a voidness of more than 20% is incorrect, and does not meet the work of the masonry of hollow material. On the basis of the analysis of a large number of research works it is concluded about the fragile work of masonry.

scholarly journals Symmetric Nature of Stress Distribution in the Elastic-Plastic Range of Pinus L. Pine Wood Samples Determined Experimentally and Using the Finite Element Method (FEM)

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 39
Author(s):  
Łukasz Warguła ◽  
Dominik Wojtkowiak ◽  
Mateusz Kukla ◽  
Krzysztof Talaśka
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Stress Distribution ◽  
Moisture Content ◽  
Tool Geometry ◽  
Wood Fibers ◽  
Data Set ◽  
Plastic Deformations ◽  
Pine Wood ◽  
Elastic Plastic

This article presents the results of experimental research on the mechanical properties of pine wood (Pinus L. Sp. Pl. 1000. 1753). In the course of the research process, stress-strain curves were determined for cases of tensile, compression and shear of standardized shapes samples. The collected data set was used to determine several material constants such as: modulus of elasticity, shear modulus or yield point. The aim of the research was to determine the material properties necessary to develop the model used in the finite element analysis (FEM), which demonstrates the symmetrical nature of the stress distribution in the sample. This model will be used to analyze the process of grinding wood base materials in terms of the peak cutting force estimation and the tool geometry influence determination. The main purpose of the developed model will be to determine the maximum stress value necessary to estimate the destructive force for the tested wood sample. The tests were carried out for timber of around 8.74% and 19.9% moisture content (MC). Significant differences were found between the mechanical properties of wood depending on moisture content and the direction of the applied force depending on the arrangement of wood fibers. Unlike other studies in the literature, this one relates to all three stress states (tensile, compression and shear) in all significant directions (anatomical). To verify the usability of the determined mechanical parameters of wood, all three strength tests (tensile, compression and shear) were mapped in the FEM analysis. The accuracy of the model in determining the maximum destructive force of the material is equal to the average 8% (for tensile testing 14%, compression 2.5%, shear 6.5%), while the average coverage of the FEM characteristic with the results of the strength test in the field of elastic-plastic deformations with the adopted ±15% error overlap on average by about 77%. The analyses were performed in the ABAQUS/Standard 2020 program in the field of elastic-plastic deformations. Research with the use of numerical models after extension with a damage model will enable the design of energy-saving and durable grinding machines.

Failure envelope of suction caisson anchors subjected to combined loadings in sand

2021 ◽  
Vol 114 ◽  
pp. 102801
Author(s):  
L. Cheng ◽  
M.S. Hossain ◽  
Y. Hu ◽  
Y.H. Kim ◽  
S.N. Ullah
Keyword(s):  
Failure Envelope ◽  
Suction Caisson ◽  
Combined Loadings

Buckling of Columns in the Presence of Creep

1956 ◽  
Vol 7 (2) ◽  
pp. 125-134 ◽  
Author(s):  
Sharad A. Patel
Keyword(s):  
Critical Time ◽  
Secondary Creep ◽  
Plastic Deformations ◽  
Creep Buckling ◽  
Elastic And Plastic Deformations

SummaryThis paper is concerned with the solution of the creep buckling of columns. Instantaneous elastic and plastic deformations, as well as the transient and secondary creep, are considered. Formulae for the critical time at which a column fails are presented for integral values of the exponents appearing in the creep law.

Upgraded Railway Front Searchlight Design Plastic Deformations by its Vibrations with Resonance Frequencies

2016 ◽  
Vol 684 ◽  
pp. 111-119 ◽  
Author(s):  
Stanislav Rafaelevich Abulkhanov ◽  
Dmitrii Sergeevich Goryainov
Keyword(s):  
Natural Frequencies ◽  
Ansys Software ◽  
Software Environment ◽  
Low Frequencies ◽  
Plastic Deformations ◽  
Vibration Resistance ◽  
First Case ◽  
Resonance Frequencies ◽  
The One ◽  
Electric Lamp

Natural frequencies of the four upgraded front searchlight designs were received in ANSYS software environment. In the first case serial front searchlight incandescent electric lamp was replaced by a LED group which was mounted on the one-piece cylinder backing. The second front searchlight design had the backing which was upgraded by a radial ribs and concentric rigidity ferrules. Analyze of the backing deformation character by vibrations with the natural frequencies established a number of design solutions which make it possible to raise front searchlight vibration resistance. By the front searchlight model were established that the natural frequencies of the searchlight with the one-piece backing appertain to the whole range of the train vibrations. Natural frequencies of the backing with perforation, rigidity ferrules, and radial ribs appertain to the low frequencies of the railway locomotive vibrations spectrum. On basis of devised methodology of analyze of the deformation and natural frequencies of the surface carrying a LED group the vibration-proof searchlight design was introduced and researched.

Comparison of Crystal Plasticity and Isotropic Hardening Predictions for Metal-Matrix Composites

1993 ◽  
Vol 60 (1) ◽  
pp. 70-76 ◽  
Author(s):  
A. Needleman ◽  
V. Tvergaard
Keyword(s):  
Volume Fraction ◽  
Matrix Material ◽  
Isotropic Hardening ◽  
Slip Systems ◽  
Matrix Composites ◽  
Plastic Deformations ◽  
Crystalline Plasticity ◽  
Planar Crystal ◽  
Crystal Model ◽  
Flow Theory Of Plasticity

In a numerical micromechanical study of the tensile properties of a metal reinforced by short whiskers, the elastic-plastic deformations of the metal are described in terms of crystalline plasticity, using a planar crystal model that allows for either two or three slip systems. Plane strain analyses are carried out for a periodic array of aligned whiskers for whisker volume fractions of 10 percent to 30 percent, and comparison is made with predictions based on a corresponding flow theory of plasticity with isotropic hardening. The predicted trend for composite strengthening with whisker volume fraction is the same for the various matrix material constitutive characterizations. It is found that the crystal model can give rise to shear localization, initiating at the sharp whisker edges. As a consequence of this localization, the stress carrying capacity eventually drops.

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