Free vibration characteristics of jute fibre reinforced composite for the determination of material properties: Numerical and experimental studies

2019 ◽  
Author(s):  
Muhammad Rizal ◽  
Amir Zaki Mubarak ◽  
Asbar Razali ◽  
Muhammad Asyraf
Keyword(s):  
Free Vibration ◽  
Material Properties ◽  
Experimental Studies ◽  
Vibration Characteristics ◽  
Jute Fibre ◽  
Reinforced Composite

An Edge-Based Smoothed Discrete Shear Gap Method for Static and Free Vibration Analyses of FG-CNTRC Plates

2019 ◽  
Vol 16 (04) ◽  
pp. 1850102 ◽  
Author(s):  
T. Nguyen-Quoc ◽  
S. Nguyen-Hoai ◽  
D. Mai-Duc
Keyword(s):  
Free Vibration ◽  
Material Properties ◽  
Volume Fraction ◽  
Plate Theory ◽  
Functionally Graded ◽  
Correction Factors ◽  
Reinforced Composite ◽  
Strain Smoothing ◽  
Edge Based ◽  
Discrete Shear Gap

In this paper, an edge-based smoothed stabilized discrete shear gap method (ES-DSG) is integrated with the C0-type high-order shear deformation plate theory (C0-HSDT) for free vibration and static analyses of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plates. The material properties of FG-CNTRC are assumed to be graded through the thickness direction according to several distributions of the volume fraction of carbon nanotubes (CNTs). The stiffness formulation of the ES-DSG based on C0-HSDT is performed by using the strain smoothing technique over the smoothing domains associated with edges of elements. This hence does not require shear correction factors. The accuracy and reliability of the proposed method are confirmed in several numerical examples.

Free Vibration Behavior of Carbon Nanotube Reinforced Composite Conical Shell Panel Under Thermal Environment

2018 ◽  
Vol 24 (8) ◽  
pp. 5915-5918
Author(s):  
S. Yogesh Krishnan ◽  
A. K Caitanya ◽  
P Tripathy ◽  
V. R Kar
Keyword(s):  
Finite Element ◽  
Carbon Nanotube ◽  
Free Vibration ◽  
Material Properties ◽  
Conical Shell ◽  
Volume Fraction ◽  
Thickness Ratio ◽  
Frequency Responses ◽  
Reinforced Composite ◽  
Shell Panel

The free vibration of carbon nanotube reinforced composite conical shell panel is examined under temperature field. In this analysis, single-walled carbon nanotube and poly(m-phenylenevinylene-co-2,5-dioctoxy-pphenylenevinylene) are used as fibre and matrix materials, respectively. The material properties are considered as temperature-dependent. The effective material properties of carbon nanotube reinforced composite panel are evaluated through the extended rule-of-mixture. The finite element model is prepared using commercially available finite element tool ANSYS APDL. An eight node Serendipity shell element (SHELL281) is used to discretize the present conical model. The displacement field is framed in the first-order shear deformation theory with six degrees of freedom. The Block Lanczos eigenvalue extraction method is used to obtain the frequency responses. In order to obtain the appropriate mesh density for the said model, the convergence study is executed for various mesh sizes. The present results are compared and validated with the previously reported results. Finally, the influences of different parameters such as length-to-thickness ratio, volume fraction and temperature on the frequency responses of the carbon nanotube reinforced composite conical shell panel are demonstrated through numerical illustrations. The results reveal that the frequency parameters of conical shell panel enhance with the volume fraction and the length-to-thickness ratio, whereas reduce with the temperature value.

COMPARISON OF VIBRATION CHARACTERISTICS FOR POSTBUCKLED FGM PLATES WITH PIEZOELECTRIC FIBER REINFORCED COMPOSITE ACTUATORS

2009 ◽  
Vol 09 (03) ◽  
pp. 533-559 ◽  
Author(s):  
XIAN-KUN XIA ◽  
HUI-SHEN SHEN
Keyword(s):  
Material Properties ◽  
Plate Theory ◽  
Vibration Characteristics ◽  
Functionally Graded ◽  
Temperature Fields ◽  
Control Voltage ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Piezoelectric Fiber

Vibration analysis is carried out for compressively loaded and thermally loaded postbuckled functionally graded material (FGM) plates with piezoelectric fiber reinforced composite (PFRC) actuators. The temperature field is assumed to be uniformly distributed over the plate surface but it varies through the thickness. The electric field has a non-zero-valued component EZ. Material properties of the substrate FGM layer are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. The material properties of both FGM and PFRC layers are assumed to be temperature-dependent. The formulations are based on a third order shear deformation plate theory and the general von Kármán-type equation that include thermo-piezoelectric effects. The numerical illustrations cover small- and large- amplitude vibration characteristics of postbuckled, mid-plane symmetric FGM plates with surface-bonded or embedded PFRC actuators under uniform and non-uniform temperature fields. The results for monolithic piezoelectric actuators, which is a special case in the present study, are compared with those of PFRC actuators. The results reveal that control voltage has a small effect on the vibration characteristics of the compressed postbuckled FGM plate with PFRC actuators but has a relatively large effect on the natural frequency of thermally postbuckled plates.

scholarly journals Strength Parameters Of Masonry Walls In Modelling Historic Constructions

2015 ◽  
Vol 18 (3) ◽  
pp. 55-64 ◽  
Author(s):  
Michał Gołębiewski ◽  
Izabela Lubowiecka ◽  
Marcin Kujawa
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Material Properties ◽  
Experimental Studies ◽  
Basic Material ◽  
Masonry Walls ◽  
The Finite Element Method ◽  
Strength Parameters ◽  
Element Size

Abstract The paper presents the determination of the basic material properties of a historic brickwork. Experimental studies were used to identify the basic material properties of bricks. The mechanical properties of the masonry, as an orthotropic homogenized material, were calculated. Then, numerical simulations using the Finite Element Method (FEM) were performed to verify the experimental outcomes. Macromodels with element sizes of 40, 20, 10 and 5 mm, and a micromodel with an element size of 5 mm were applied. The results were compared with experimental data and results available in literature.

On Experimental Studies of Longitudinal and Flexural Wave Propagations: An Annotated Bibliography

1986 ◽  
Vol 39 (6) ◽  
pp. 853-865 ◽  
Author(s):  
M. M. Al-Mousawi
Keyword(s):  
Wave Propagation ◽  
Cross Section ◽  
Material Properties ◽  
Experimental Studies ◽  
Flexural Wave ◽  
Experimental Investigations ◽  
Velocity Impact ◽  
Flexural Wave Propagation ◽  
The Impact

Experimental investigations in the field of longitudinal wave propagation in beams are plentiful; however, experimental studies of flexural wave propagation problems are scarce and are restricted mainly to uniform and infinite structures where the effects of reflected waves are not generally included. This review is mostly restricted to low velocity impact and does not cover the so-called high velocity impact such as those of bullets and explosives. In addition to a brief survey of classical work related to impact, this article covers publications related to experimental studies of longitudinal and flexural elastic waves due to impact. This includes the longitudinal, central as well as eccentric impact and transverse impact of two bars and the impact achieved by sphere impinging on a beam. Many workers used experimental findings to study the adequacy of various theoretical solutions of the wave propagation problem such as those by Pochhammer and Chree, Euler–Bernoulli, and the Timoshenko beam theory. The revival of interest in the recent years is due to, among other things, the advancement of experimental equipment and measurement techniques for data acquisition of stress waves and associated signals. An important application of transient waves is their use for the determination of material properties under various loading conditions and strain rates that can be studied by the split Hopkinson pressure bar techniques. The problem of longitudinal and flexural waves in bars with discontinuities of cross section are covered, and some publications on fracture of materials due to bending waves are also included. Experimental investigations demonstrate the effect of abrupt change of cross section and/or material properties on reflected and transmitted waves where reflections are to be taken into consideration when estimating the level of stresses and strains in finite beam with discontinuities. In the field of flexural wave propagation, comparison of theoretical predictions with experimental results verified and validated the adequacy of the Timoshenko theory for the determination of bending strain in finite structures, a one-dimensional theory that takes into account the effect of shear deformation and rotatory inertia.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

Energetic properties of peat saturated with petroleum products

2020 ◽  
Vol 13 (2) ◽  
pp. 105-109
Author(s):  
E. S. Dremicheva
Keyword(s):  
Crude Oil ◽  
Diesel Fuel ◽  
Energy Use ◽  
Experimental Studies ◽  
Calorific Value ◽  
Petroleum Products ◽  
Ash Content ◽  
Motor Oil ◽  
Initial Sample

This paper presents a method of sorption using peat for elimination of emergency spills of crude oil and petroleum products and the possibility of energy use of oil-saturated peat. The results of assessment of the sorbent capacity of peat are presented, with waste motor oil and diesel fuel chosen as petroleum products. Natural peat has been found to possess sorption properties in relation to petroleum products. The sorbent capacity of peat can be observed from the first minutes of contact with motor oil and diesel fuel, and significantly depends on their viscosity. For the evaluation of thermal properties of peat saturated with petroleum products, experimental studies have been conducted on determination of moisture and ash content of as-fired fuel. It is shown that adsorbed oil increases the moisture and ash content of peat in comparison with the initial sample. Therefore, when intended for energy use, peat saturated with petroleum products is to be subjected to additional drying. Simulation of net calorific value has been performed based on the calorific values of peat and petroleum products with different ratios of petroleum product content in peat and for a saturated peat sample. The obtained results are compared with those of experiments conducted in a calorimetric bomb and recalculated for net calorific value. A satisfactory discrepancy is obtained, which amounts to about 12%. Options have been considered providing for combustion of saturated peat as fuel (burnt per se and combined with a solid fuel) and processing it to produce liquid, gaseous and solid fuels. Peat can be used to solve environmental problems of elimination of emergency spills of crude oil and petroleum products and as an additional resource in solving the problem of finding affordable energy.

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