Time dependent strength properties of materials

1989 ◽  
pp. 216-225
Author(s):  
L. Sentler
Keyword(s):  
Strength Properties ◽  
Time Dependent ◽  
Properties Of Materials

scholarly journals About the possibility of creation of sealed strong structures of rocket and space equipment FDM printing methods

2021 ◽  
Author(s):  
Oleksandr Salenko ◽  
Kostyantyn Avramov ◽  
Іgor Derevianko ◽  
О. Samusenko ◽  
V. Rogulin ◽  
...  
Keyword(s):  
Shelf Life ◽  
Strength Properties ◽  
Space Technology ◽  
Printing Technology ◽  
Specific Strength ◽  
Properties Of Materials ◽  
Membrane Type

The work shows the possibility of manufacturing products for rocket and space technology using the additive FDM-printing technology. The object of research is the nozzle plugs of the "membrane" type. Taking into account the specific-strength properties of the product during its operation during operation, as well as the features of the FDM-process, the design was optimized, the regularities of the formation of its properties were established. An impregnation technology has been developed to seal the product. The equipment was designed and pneumatic tests were carried out. The properties of materials were investigated taking into account their guaranteed shelf life for 12 years of operation under accelerated climatic tests. It is shown that the production of products by FDM-printing methods is promising and expedient, since the properties being formed are predictable, achievable and stable.

Behavior of Circular Footings and Plate Anchors Embedded in Permafrost

1974 ◽  
Vol 11 (4) ◽  
pp. 531-553 ◽  
Author(s):  
B. Ladanyi ◽  
G. H. Johnston
Keyword(s):  
Mathematical Model ◽  
Bearing Capacity ◽  
Soil Mechanics ◽  
Normal Pressure ◽  
Strength Properties ◽  
Frozen Soil ◽  
Time Dependent ◽  
Nonlinear Viscoelastic ◽  
Permafrost Soils ◽  
Failure Loads

The purpose of this paper is to develop a method for predicting the creep settlement and the bearing capacity of frozen soils under deep circular loads. The theory uses experimentally determined creep parameters of frozen soil and is intended to be applicable to the design of deep circular footings and screw anchors embedded in permafrost soils. On the basis of available experimental evidence, it was concluded that a mathematical model different from that usual in soil mechanics should be used in solving the time-dependent bearing capacity problem of such footings. The solution proposed in the paper was obtained by using the mathematical model of an expanding spherical cavity in a nonlinear viscoelastic-plastic medium with time, temperature, and normal pressure dependent strength properties. For a given footing or anchor, the theory furnishes either isochronous load-displacement curves, or load-creep rate curves, or a time-dependent bearing capacity for which formulas and graphs of nonlinear elastic-plastic bearing capacity factors are supplied.The theoretical predictability of creep rates and ultimate failure loads was checked against the results of screw anchor tests carried out by the Division of Building Research, N.R.C.C., at a permafrost site in Thompson, Manitoba. It was found that the use in the theory of the creep parameters determined by creep-pressuremeter tests performed at the site, resulted in a satisfactory agreement between the predicted and the observed behavior.

scholarly journals Creation of Sealed Strong Structures of Rocket and Space Equipment FDM Printing Methods by Ultem ™ 9085 Pei Plastic

2021 ◽  
Vol 5 (3) ◽  
Author(s):  
Oleksandr Salenko ◽  
Igor Derevianko ◽  
О. Samusenko ◽  
Kostyantin Avramov ◽  
O. Lithot ◽  
...  
Keyword(s):  
Shelf Life ◽  
Strength Properties ◽  
Space Technology ◽  
Printing Technology ◽  
Specific Strength ◽  
Properties Of Materials ◽  
Membrane Type

The work shows the possibility of manufacturing products for rocket and space technology using the additive FDM-printing technology. The object of research is the nozzle plugs of the "membrane" type. Considering the specific-strength properties of the product during its operation during operation, as well as the features of the FDM-process, the design was optimized, the regularities of the formation of its properties were established. An impregnation technology has been developed to seal the product. The equipment was designed, and pneumatic tests were carried out. The properties of materials were investigated considering their guaranteed shelf life for 12 years of operation under accelerated climatic tests. It is shown that the production of products by FDM-printing methods is promising and expedient, since the properties being formed are predictable, achievable, and stable.

THERMODYNAMICS OF MECHANICAL OSCILLATIONS IN CRYSTALLINE SUPERLATTICES

2007 ◽  
Vol 21 (06) ◽  
pp. 917-930 ◽  
Author(s):  
S. K. JAĆIMOVSKI ◽  
J. P. ŠETRAJČIĆ ◽  
V. M. ZORIĆ ◽  
B. S. TOŠIĆ ◽  
V. D. SAJFERT ◽  
...  
Keyword(s):  
Specific Heat ◽  
Bulk Sample ◽  
Time Dependent ◽  
Superconducting Properties ◽  
Specific Heats ◽  
Mechanical Oscillations ◽  
Phonon Spectra ◽  
Thermal Conducting ◽  
Properties Of Materials ◽  
Bulk Structures

Phonon spectra as well as thermodynamic characteristic of superlattice are analyzed using the method of two-time dependent Green's functions. Free and internal energy of the system as well as specific heat and entropy are found. The temperature behavior of superlattice specific heat is compared with specific heats of bulk structures and thin films. It was shown that at extremely low temperature, superlattice and film specific heats are practically equal and considerably lower than specific heat of bulk sample. The consequences of this fact to the thermal, conducting and superconducting properties of materials was discussed.

scholarly journals Time dependent properties of sandstones and their effects on mine stability

2013 ◽  
Vol 5 (2) ◽  
pp. 897-916 ◽  
Author(s):  
M. Alber
Keyword(s):  
Large Scale ◽  
Hanging Wall ◽  
Strength Properties ◽  
Time Dependent ◽  
Seismic Events ◽  
Mining District ◽  
Delayed Response ◽  
Underground Excavations ◽  
Dependent Failure ◽  
Mine Stability

Abstract. Large scale stress redistribution around longwall panels in coal mines puts rock masses in the vicinity of the underground excavations close to failure. While immediate failure is reflected for example by instantaneous seismic events, there is also a delayed response of the rock mass as noted from decaying seismicity during non-operating times. Sandstone samples from the hanging wall of a coal seam in the Ruhr coal mining district in Germany have been subjected to conventional strength, creep and relaxation tests. From creep and relaxation tests estimates of time dependent strength properties are derived. Numerical modeling was employed to delineate zones of states of stress around underground excavations which are prone to time dependent failure.

scholarly journals The strength properties dependence of aluminum materials on the ZrO2 nanoparticles concentration

2019 ◽  
Vol 485 (6) ◽  
pp. 704-707
Author(s):  
V. V. Mironov ◽  
L. E. Agureev ◽  
Zh. V. Eremeeva ◽  
V. I. Kostikov
Keyword(s):  
Zirconium Oxide ◽  
Pure Aluminum ◽  
Strength Properties ◽  
Zro2 Nanoparticles ◽  
Noticeable Increase ◽  
Nanoparticles Concentration ◽  
Properties Of Materials ◽  
Nano Additives ◽  
Cold Pressed ◽  
Zirconium Oxide Nanoparticles

New data were obtained on the effect of small additions of zirconium oxide nanoparticles on the strength properties of powder matrices based on pure aluminum, including those with the addition of 1.5% copper cold pressed and sintered in forevacuum. It is shown that even with an insignificant concentration of nano-additives, there is a noticeable increase in the mechanical properties of materials: tensile strength, bending, compression, and yield strength.

scholarly journals Analysis of the Generation of Vibration Signals under Uniaxial Loading of Materials Using the Coherent Properties of Laser Radiation

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2046
Author(s):  
Petr Louda ◽  
Artem Sharko
Keyword(s):  
Strength Properties ◽  
Experimental Investigations ◽  
Strain Diagram ◽  
Physical Processes ◽  
Vibration Signals ◽  
Information Parameter ◽  
Vibrational Signals ◽  
Discrimination Level ◽  
Properties Of Materials

The present article describes the results of theoretical and experimental investigations of the force response of materials to external tensile stresses. The method used is based on remote precision measurements of the amplitudes of the harmonics of vibration signals and synchronous fixation of deformations under load. It was determined that the shape of the propagating acoustic signal depends not only on the bias time, but also on the frequency. In addition, fixation of the moments of occurrence of the vibrational signals and determination of the number of excesses in the amplitudes of harmonics over the discrimination level allows structural models to be studied in order to diagnose the strength properties of materials under dynamic loading of solids. The experimental setup consisted of a P100 Labtest-2 tearing machine providing a loading speed of 6.22 mm/min, a Polytech PSV–400 vibrometer including lasers, and a computer. Measurements were made at frequencies of 0.4, 1.6, and 40 kHz. An analysis of the mathematical models of the occurrence and propagation of acoustic signals in a material under load is presented, and the features of their application are reported. Transferring the moments of occurrence of vibrational signals to a strain diagram from the applied load allows the development of physical processes of hardening and destruction of materials to be traced. The occurrence of vibrational signals under load can be used as an information parameter for the diagnosis of developing defects in the structure of materials under load.

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