Mechanical Properties of Raw and Vulcanized Rubbers during Periodic Deformation

1940 ◽  
Vol 13 (2) ◽  
pp. 316-325 ◽  
Author(s):  
M. Kornfel'd ◽  
V. Poznyak
Keyword(s):  
Mechanical Properties ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
General Regularity ◽  
Technical Problems ◽  
Automobile Tire ◽  
Periodic Deformation ◽  
Wide Range ◽  
Relative Compression ◽  
Work Of Deformation

Abstract The construction of an apparatus for measuring the modulus of elasticity and the mechanical losses in raw and vulcanized rubbers during the periodical deformation of compression is described. With the aid of this device it is possible to measure these characteristics at frequencies from 10 to 50 cycles per second for relative compression deformations from 1 to 50 per cent and in a wide range of temperatures. The relation between temperature and modulus of elasticity and mechanical losses was studied at 30 cycles per second for various grades of raw and vulcanized rubbers and a general regularity of this dependence was determined. In the solution of technical problems such as the construction of automobile tire treads, the behavior of rubber under conditions of rapidly changing periodic deformation is highly important. Here the two characteristics of rubber: the dynamic modulus of elasticity and the magnitude of that part of work of deformation which is irreversibly spent during one cycle (mechanical losses) are of the greatest interest. In previous studies of these properties, three basic methods have been used:

Relativity Analysis between Dynamic and Static Modulus of Elasticity on Different Thickness Wood-Plastic Structural Plates

2011 ◽  
Vol 121-126 ◽  
pp. 4254-4258 ◽  
Author(s):  
Gui Wen Yu ◽  
Ying Cheng Hu ◽  
Ji You Gu
Keyword(s):  
Mechanical Properties ◽  
Nondestructive Testing ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Bending Test ◽  
Three Point Bending ◽  
Static Modulus ◽  
Dynamic Modulus Of Elasticity ◽  
Static Modulus Of Elasticity ◽  
Different Thickness

The relativity was evaluated between dynamic modulus of elasticity (MOE) and static MOE, in order to assess the potential of using nondestructive testing (NDT) method as a checking tool for mechanical properties of wood-plastic structural plates. The dynamic MOE was evaluated on a FFT system, and the static MOE was determined by three point bending test. All of specimens were made of polyethylene（PE）and poplar flour. A significant correlation between the dynamic MOE and the static MOE was obtained from relativity analysis. These results suggest that the NDT method could be appropriate to estimate the dynamic MOE of specimens with different thickness.

scholarly journals Durability of a New Aerogel Cement-Based Rendering System under Distinct Accelerated Aging Conditions

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5413
Author(s):  
Joana Maia ◽  
Marco Pedroso ◽  
Nuno M. M. Ramos ◽  
Inês Flores-Colen ◽  
Pedro F. Pereira ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Liquid Water ◽  
Adhesive Strength ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Accelerated Aging ◽  
Widespread Application ◽  
Freeze Thaw ◽  
The Matrix ◽  
Aging Conditions

The widespread application of innovative thermal enhanced façade solutions requires an adequate durability evaluation. The present work intends to assess the durability of a new aerogel cement-based rendering system through the adaptation of different accelerated aging cycles, such as heating–freezing, freeze–thawing, and heat–cold. Several mechanical properties and also capillary and liquid water absorptions were tested for uncoated and coated specimens. A decrease in the mechanical strength, especially after freeze–thaw cycles, was observed. However, the water action promoted the late hydration of the cement paste contributing to the densification of the matrix and, consequently, the increase of the adhesive strength. Additionally, a decrease in the dynamic modulus of elasticity and an increase in the Poisson’s ratio were observed after aging, which indicates a higher capacity of the render to adapt to substrate movements, contributing to a reduction of cracking.

scholarly journals THERMOPHYSICAL AND PHYSICO-MECHANICAL CHARACTERISTICS OF EPOXYURETHANE COMPOSITES

2020 ◽  
Vol 86 (8) ◽  
pp. 134-143
Author(s):  
Larisa Yashenko
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Sodium Silicate ◽  
Modulus Of Elasticity ◽  
Relative Deformation ◽  
Scanning Calorimetry ◽  
Physicomechanical Characteristics ◽  
Relative Compression ◽  
Inorganic Constituents ◽  
The Eu

Epoxy urethane composites (EU) have been developed based on polyisocyanate (PIC), epoxy resin (ED-20), and sodium silicate (SS). The results of the study of the influence of the ratio of the components of the EU on their thermophysical and physicomechanical characteristics are presented. The method ofdifferential scanning calorimetry revealed thatthese systems do not have clear temperature transitions, which indicates a fairly homogeneous and rigid structure. Studies of thermal properties by the method of dynamic thermogravimetry have shown that as the amount of sodium silicate increases, the temperature of the onset of decomposition of the EU is shifted by 20 ° C towards lower temperatures. At the same time, there is a slowdown in the decomposition of epoxy urethanes (weight loss is 12-14%), due to the presence of heterocyclic isocyanurate fragments, which is inherent in its own high thermal stability. The mechanical properties of the EU, such as compressive strength, modulus of elasticity, relative compression deformation, flexural strength, and water absorption, are determined depending on the ratio of components. High mechanical properties are shown regardless of the inorganic component amount. The modulus of elasticity, strength, and relative deformation in compression is in the range of 1916.4 - 4187.6 MPa, 117.4 - 133.1 MPa, and 24.7-30.4%, respectively. The highest flexural strengths are characterized by the EC composition of the PIC / SS / ED-20 = 80/20/20, and the lowest - the EC composition of the PIC / SS / ED-20 = 70/30/20. The results of the studies show that, by changing the ratio of organic and inorganic constituents in the EC, it is possible to regulate the thermal stability and physicomechanical properties of epoxy urethane composites depending on their purpose.

scholarly journals Prediction of Mechanical Properties of Hardwood Species Using the Longitudinal Vibration Acoustic Method

2021 ◽  
Vol 71 (4) ◽  
pp. 391-400
Author(s):  
Kayode Olaoye ◽  
Lawrence Aguda ◽  
Bolade Ogunleye
Keyword(s):  
Mechanical Properties ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Longitudinal Vibration ◽  
Modulus Of Rupture ◽  
Damping Factor ◽  
Acoustic Parameters ◽  
Static Modulus ◽  
Hardwood Species ◽  
Static Modulus Of Elasticity

Abstract Acoustic test methods such as longitudinal vibration have been developed to predict the elastic properties of wood. However, attention has not been shifted to using this method to predict other mechanical properties, especially on Nigeria's preferred, and lesser-used wood species. Thus, we further investigate relationships among mechanical and acoustic properties of selected hardwood species with a view of predicting the mechanical properties of wood from acoustic parameters. Clear wood samples (324) of 20 by 20 by 20 mm3 were collected axially from Albizia adianthifolia, Gmelina arborea, Delonix regia, and Boscia anguistifolia trees, and conditioned before testing. The longitudinal vibration method was adopted to test for the dynamic (acoustic) parameters and properties (fundamental frequency, damping factor, dynamic modulus of elasticity, sound velocity, specific elastic modulus, radiation coefficient, acoustic conversion efficiency, acoustic impedance) while the universal testing machine was used to test for the mechanical properties (static modulus of elasticity, modulus of rupture, maximum compression strength parallel to grain). The damping factor, dynamic modulus of elasticity, and acoustic impedance were the best acoustic parameters that significantly correlated with the static modulus of elasticity (−0.57, 0.81, 0.76), modulus of rupture −0.64, 0.82, 0.85) and maximum compression strength parallel to grain (−0.52, 0.78, 0.84), respectively. There was a significant difference in the mechanical properties with respect to species, thus A. adianthifolia and G. arborea were mechanically better than D. regia and B. anguistifolia for construction or structural purposes. This study revealed that additional new acoustic measures are suitable for inferring mechanical wood properties.

Predicting mechanical properties of clear wood from Acacia mangium provenances using ultrasound

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 8309-8319
Author(s):  
Doan Van Duong ◽  
Masumi Hasegawa
Keyword(s):  
Mechanical Properties ◽  
Compression Strength ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Significant Positive Correlation ◽  
Correlation Coefficients ◽  
Acacia Mangium ◽  
Longitudinal Direction ◽  
Modulus Of Rupture ◽  
Clear Wood

Ultrasound was considered as a means for determining mechanical properties of clear wood in six different Acacia mangium provenances from a trial forest planted in Vietnam. A total of 30 trees (5 trees from each provenance) with no major defects were selected, and a 50-cm-long log was obtained at 1.3 m above the ground from each tree for the assessment of mechanical properties. The measured average ultrasound velocities for provenances tested in the longitudinal direction ranged from 4094 m/s to 4271 m/s. The predicted average dynamic modulus of elasticity (Ed) values varied from 7.42 GPa to 8.70 GPa among provenances. The Ed indicated significant positive correlation coefficients with modulus of elasticity (0.64 to 0.96), modulus of rupture (0.44 to 0.87), and compression strength (0.54 to 0.92) for provenances examined in this study. The results indicated that the use of ultrasound was feasible to determine the mechanical properties of A. mangium provenances planted in Vietnam.

scholarly journals Experimental Investigation of Material Properties and Self-Healing Ability in a Blended Cement Mortar with Blast Furnace Slag

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2564
Author(s):  
Seunghyun Na ◽  
Wenyan Zhang ◽  
Madoka Taniguchi ◽  
Nguyen Xuan Quy ◽  
Yukio Hama
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Blended Cement ◽  
Self Healing ◽  
Replacement Ratio ◽  
Dynamic Modulus Of Elasticity ◽  
Different Types ◽  
Furnace Slag

This paper presents the results of an experimental investigation on the material properties and self-healing ability of a blended cement mortar incorporating blast furnace slag (BFS). The effect of different types and Blaine fineness of BFS on the material properties and self-healing was investigated. Thirteen cement mixtures with BFS of different types and degrees of Blaine fineness are tested to evaluate the mechanical properties, namely compressive strength, bending strength, freeze–thaw, and accelerated carbonation. The pore structure is examined by means of mercury intrusion porosimetry. Seven blended mortar mixtures incorporating BFS for cement are used to evaluate the mechanical properties after applying freeze–thaw cycles until the relative dynamic modulus of elasticity reached 60%. The experimental results reveal that incorporating BFS improves the mechanical properties and self-healing ability. In the investigation of self-healing, smaller particle and high replacement ratios of BFS contribute to increasing the relative dynamic modulus of elasticity and decreasing the carbonation coefficient in the mortar after re-water curing. Moreover, BFS’s larger particles and high replacement ratio are found to provide better self-healing ability. A regression equation is created to predict the relative dynamic modulus of elasticity in mortar considering the Blaine fineness, BFS replacement ratio, and curing conditions.

Study on Durability of C100 Concrete in Shenyang Royal WAN XIN Hotel

2009 ◽  
Vol 405-406 ◽  
pp. 19-23
Author(s):  
Da Li Zhang ◽  
Yuan Wang ◽  
Cui Hong Chen
Keyword(s):  
Mechanical Properties ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
High Strength Concrete ◽  
Evaluation Method ◽  
Chloride Ion ◽  
High Strength ◽  
Test Results ◽  
Strength Concrete

Durability of C100 concrete in Shenyang WAN XIN Hotel engineering including long-term mechanical properties, dynamic modulus of elasticity, and chloride ion resistance was tested and analyzed. Test results appeared that C100 concrete had very good density and extremely good durability. Simultaneously we suggest improving the evaluation method to test the durability of super-high strength concrete in order to enhance the evaluation level effectively. It will provide one according of durability to apply super-high strength concrete.

scholarly journals ASSESSMENT OF MIX PROPORTIONS FOR DEVELOPING LIGHTWEIGHT CEMENTITIOUS COMPOSITES WITH WOOD WASTES

2017 ◽  
Vol 41 (1) ◽  
Author(s):  
Monica Garcez ◽  
Estela Garcez ◽  
Aline Machado ◽  
Darci Gatto
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Water Absorption ◽  
Bulk Density ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Void Ratio ◽  
Eucalyptus Grandis ◽  
Cementitious Composites ◽  
Wood Composites

ABSTRACT The main objective of this work was to assess mix proportions for developing lightweight cementitious composites, manufactured with Eucalyptus grandis sawdust. Different wood:cement, water:cement and admixture:cement ratios were used to evaluate physical (water absorption, void ratio and density) and mechanical (compressive strength, static and dynamic modulus of elasticity) properties of the cement-wood composites. Results shows that, bulk density is directly proportional to the compressive strength and elastic modulus, and inversely proportional to the percentage of timber, considering composites with same water:cement ratio, without superplasticizer. The performance of the cement-wood composites, regarding mechanical properties, can be improved if superplasticizer is used to increase paste fluidity. Higher values of bulk density are related to lower void ratio and water absorption and higher compressive strength and modulus of elasticity.

Mechanical Properties of Cement Composite with Material Based on Waste Marble Powder and Crushed Limestone

2017 ◽  
Vol 1144 ◽  
pp. 9-13
Author(s):  
Lukáš Hlubocký ◽  
Zdeněk Prošek
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
Construction Industry ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Cement Composite ◽  
Waste Materials ◽  
Marble Powder ◽  
Crushed Limestone

This paper deals with the use of waste materials from processing of stone in the construction industry. The tested mixtures consisted of Portland cement CEM I 42.5 R, micronized waste marble powder and crushed waste limestone. The article examines the effect of varying the amount of waste on the mechanical properties of the cement composite. At first, samples were tested non-destructively for determine the dynamic modulus of elasticity and then were tested destructively for determine tensile bending and compressive strength.

scholarly journals Fine sepiolite addition to air lime-metakaolin mortars

Clay Minerals ◽  
2011 ◽  
Vol 46 (4) ◽  
pp. 621-635 ◽  
Author(s):  
S. Andrejkovičová ◽  
E. Ferraz ◽  
A. L. Velosa ◽  
A. S. Silva ◽  
F. Rocha
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Adsorption Properties ◽  
Lime Mortar ◽  
The Core ◽  
Lime Mortars ◽  
Low Humidity ◽  
Repair Mortars

AbstractLime-based mortars with admixtures of metakaolin (10, 20 and 30 wt.%) and fine sepiolite (5 wt.%) were prepared with the aim of facilitating their use as repair mortars in low-humidity conditions. The mechanical properties and the dynamic modulus of elasticity were studied after 28, 90 and 180 days of curing. With an increasing amount of metakaolin in lime mortars, improved mechanical strength was observed mainly after 90 days. Addition of fine sepiolite, due to its adsorption properties for storing water for later supply to the mortar system and its microfibrous morphology, led to an improvement of compressive and flexural strength of blended air lime/air lime-metakaolin mortars, espec ially at later ages of curing. Incorporation of fine sepiolite into air lime-metakaolin mortars resulted in comprehensive densification of the core of the mortars. Air lime mortar containing 5 wt.% of fine sepiolite and 20 wt.% of metakaolin appears to be an optimal admixture.

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