Model Testing as Applied to Strength of Materials

1933 ◽  
Vol 1 (2) ◽  
pp. 79-84
Author(s):  
R. E. Peterson
Keyword(s):  
Stress Analysis ◽  
Strength Properties ◽  
Model Testing ◽  
Strength Of Materials ◽  
Impact Tests ◽  
Properties Of Materials ◽  
Law Of Similarity ◽  
The Law ◽  
Use Of Models

Abstract This paper is primarily concerned with the effect of size on the ordinary strength properties of materials. The use of models in stress analysis is described briefly. The effect of size in tension, fatigue, and impact tests is considered in detail. Possible explanations for departure from the law of similarity are stated.

Over 70% Fill Factor of All‐Polymer Solar Cells Guided by the Law of Similarity and Intermiscibility

Solar RRL ◽  
2021 ◽  
pp. 2100019
Author(s):  
Shaorong Huang ◽  
Peiqing Cong ◽  
Zuoji Liu ◽  
Feiyan Wu ◽  
Chenxiang Gong ◽  
...  
Keyword(s):  
Solar Cells ◽  
Fill Factor ◽  
Polymer Solar Cells ◽  
Law Of Similarity ◽  
The Law

Stress Analysis of Cord Adhesion Tests — A Route to Improved Tests

1981 ◽  
Vol 54 (4) ◽  
pp. 835-856 ◽  
Author(s):  
R. A. Ridha ◽  
J. F. Roach ◽  
D. E. Erickson ◽  
T. F. Reed
Keyword(s):  
Stress Analysis ◽  
Small Strain ◽  
Good Alternative ◽  
Strength Properties ◽  
Square Root ◽  
Rubber Compound ◽  
Adhesion Test ◽  
Pullout Force ◽  
Pull Through ◽  
Maximum Stresses

Abstract Stress fields were calculated in tire cord adhesion test specimens as a route to the development of improved wire adhesion tests. The calculated stresses were analyzed in order to predict the location of initiation of debonding and to assess the dependence of the cord pullout force on the modulus of the rubber compound. The computational results were validated by experiments on a variety of cord/rubber samples. Conclusions drawn from this study are as follows: The analyzed pull-through test for adhesion of steel wires has a serious drawback. Its major deficiency lies in the presence of a slot under the rubber block specimen. Maximum stresses are consistently higher at the slot edges than at the cord/rubber interface. This is responsible for: (a) initiation of failure at the slot edges rather than at the cord/rubber interface, (b) considerable rubber coverage, and (c) dependence of the cord pullout force on the strength properties of rubber. The test is more likely to test the strength of the rubber compound than it is to test the strength of adhesion. The TCAT test represents a significant improvement over the pull-through test with regard to the location of failure. Stresses at the cord/rubber interface are higher than elsewhere within the sample. Stresses along the cord show a high peak at the cord's embedded end. This highly localized peak initiates debonding at the embedded end and yields good reproducibility (failure is very unlikely to initiate elsewhere). Experiments on the TCAT specimen show a reproducibility of within 4.2%. Maximum stresses in the TCAT specimen vary with approximately the square root of the rubber modulus. Thus, while the TCAT may be an excellent choice for wire studies involving a single control compound, it may be limited when used in compounding studies and other tire applications which involve changes in the rubber properties. In such studies, the dependence on rubber modulus is viewed as a limitation of TCAT because: (a) unintentional changes in the rubber modulus will affect the cord pullout force and can lead to erroneous assessment of the adhesive strength, and (b) intentional changes in the rubber modulus cannot be simply factored out by a square root rule. Our experiments show that the exponent of the rubber modulus depends on how the modulus change is achieved. There are also many definitions of the modulus and several techniques for determining its value. Experiments on the SWAT test show a pullout force proportional to a lower exponent of the rubber modulus than the exponent in the TCAT test. Reproducibility is at 5.6%, i.e., somewhat poorer than the TCAT. The width of the sample, and the presence of cord reinforcements within that width (in addition to the cords being tested), are expected to change the stress distribution along the cords from the distribution in the TCAT test. The 9.5 mm × 9.5 mm steel-backed specimen represents a good alternative for adhesion tests in compounding studies and tire applications. Although its reproducibility is not as good as those of the TCAT and SWAT tests, its independence from the rubber properties and its ease of sample preparation make it a good alternative. Finite element stress analysis of adhesion tests can provide useful information for assessing alternative tests and developing improved tests. Although total cord pullout normally takes place after large deformations in the rubber, simplified, small strain material models can provide a good indication of the behavior of adhesion test specimens.

Corrosion Engineering And Corrosion Science

CORROSION ◽  
1963 ◽  
Vol 19 (6) ◽  
pp. 199t-204t ◽  
Author(s):  
M. G. FONTANA
Keyword(s):  
Mechanical Properties ◽  
Stress Analysis ◽  
Human Nature ◽  
Mechanical Engineering ◽  
Electrical Engineering ◽  
Quality Of Work ◽  
Physical Chemical ◽  
Corrosion Science ◽  
Properties Of Materials

Abstract The corrosion scientist and corrosion engineer are complementary; their efforts are synergistic in solving problems of corrosion control. The broad background of a corrosion engineer capable of covering the entire field of corrosion engineering includes knowledge of chemistry, metallurgy, physical, chemical and mechanical properties of materials, electrical engineering, mechanical engineering, biology, stress analysis, economics, human nature and many other fields. The corrosion scientist and corrosion engineer should regard each other with equal esteem, the only basis for evaluating the other's efforts being quality of work.

scholarly journals Analysis of steady flow in a circular cylindrical pipe with hydraulically smooth walls

2020 ◽  
Author(s):  
В.А. Павловский
Keyword(s):  
Steady Flow ◽  
Reynolds Numbers ◽  
Explicit Representation ◽  
Turbulent Regime ◽  
Cylindrical Pipe ◽  
Pipe Axis ◽  
Law Of Similarity ◽  
The Law ◽  
The Relationship ◽  
Analytical Expressions

Анализируются формулы для скоростей и сопротивлений при установившемся течении несжимаемой вязкой жидкости в круглой цилиндрической трубе. Используется закон подобия скоростей при турбулентном режиме течения для получения представления коэффициента сопротивления в явном виде. Рассматривается связь между числами Рейнольдса, вычисляемых по средней и по динамической скоростями. Сформулирован принцип нахождении профилей скорости по закону сопротивления. Приведены аналитические выражения для всего универсального профиля скоростей. Приводится алгоритм построения кривой сопротивления по профилю скоростей в универсальных координатах. Предлагается единая формула для коэффициента сопротивления при любом режиме течения и формула для учёта отклонения от логарифмики на профиле скоростей в области вблизи оси трубы. The formulas for the velocities and resistances in the steady flow of an incompressible viscous fluid in a round cylindrical pipe are analyzed. The law of similarity of velocities in the turbulent regime is used to obtain an explicit representation of the drag coefficient. The relationship between the Reynolds numbers calculated by the average and dynamic speeds is considered. The principle of finding velocity profiles according to the law of resistance is formulated. Analytical expressions are given for the for any flow regime and a formula for taking into account deviations from the logarithm on the velocity profile in the region near the pipe axis.

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.

scholarly journals Simulation of BHA sticking elimination effectiveness using jarring devices

2018 ◽  
pp. 64-71
Author(s):  
V. M. Charkovskyi ◽  
M. М. Slepko
Keyword(s):  
Mathematical Model ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Queuing Theory ◽  
Strength Properties ◽  
Laboratory Research ◽  
Rock Destruction ◽  
The Law ◽  
Device Use ◽  
Restraining Force

A stochastic mathematical model of the jarring device use effectiveness for releasing the stuck BHA was studied based on Monte-Carlo method of probability of the corresponding result. Distribution histograms were designed and the law of sticking force distributionp in various cases was defined. The conditions, when the probability of growth of the restraining force is unacceptably high were defined. The time of jarring and the number of impacts for probable tool release were defined using queuing theory elements. The results of laboratory research of strength properties of some Precarpathian rocks were given and approach for their accounting as criteria of rock destruction during jarring were proposed.

scholarly journals Increasing the performances of low permeable cement composites

Vestnik MGSU ◽  
2021 ◽  
pp. 1346-1356
Author(s):  
Valery S. Lesovik ◽  
Roman S. Fediuk
Keyword(s):  
Effective Diffusion ◽  
Control Sample ◽  
Vapor Permeability ◽  
Low Permeability ◽  
Second Phase ◽  
Cement Composites ◽  
Composite Binder ◽  
Wide Range ◽  
Law Of Similarity ◽  
The Law

Introduction. The purpose of the article is to expand the range of compositions for special structures, which will allow them to be operated in extreme conditions. To achieve this goal, a number of tasks have been solved containing ways to improve the efficiency of composites, incl. low-permeability ones. Materials and methods. The research methodology includes a system of transdisciplinary approaches that evaluate the composite as a complex system, taking into account the provisions of geomimetics, such as the law of similarity, the law of affinity of structures, technogenic metasomatism, and micromechanics of composite media. Results. A wide range of cement concretes has been created for unique objects: low-permeability (for protective objects, reservoirs and hydraulic structures). The developed composites have the following performance characteristics (the results for the control sample are given in parentheses): water absorption by weight — 2.5 % (6.1 %), waterproof grade — W14 (W10), air permeability — 0.0253 cm3/s (0.0565 cm3/s), vapor permeability — 0.0021 mg/(m-h-Pa) (0.0030 mg/(m-h-Pa)), effective diffusion coefficient — 1.34 · 10–4 cm2/s (1.56 · 10–4 cm2/s). Conclusions. The similarity in the work of the components of different composite binders, incl. During the two-stage hydration of clinker minerals, in particular, in the first phase, the formation of low-density compounds of different phases occurs, and in the second phase, the binding of calcium hydroxide to low-basic crystalline hydrates occurs. The increase in the activity of the composite binder is due to the synergistic effect of a number of reasons: amorphous silica-containing components bind Ca(OH)2, released during the hydration of clinker minerals, in the second generation CSH(I); limestone particles clog the pores, compacting the structure; and fly ash microspheres are centers of crystallization of new growths.

The Law of Similarity

2017 ◽  
pp. 341-354
Author(s):  
V.M. Bekhterev ◽  
Lloyd H. Strickland
Keyword(s):  
Law Of Similarity ◽  
The Law
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