Showing papers in "Engineering Solid Mechanics in 2016"

Changes in the topology of a concrete porous space in interactions with the external medium

Abstract: Article history: Received 6 March, 2016 Accepted 27 May 2016 Available online 28 May 2016 The article is devoted to some aspects of research of hostile environment influence on the concrete durability. The mechanism of formation of chaotically diversified difficult structure is described. Chemical interactions of cement with active components of diffusion in steam space are examined. Measures for receiving conditions under which the volume of products of reaction will be equal to the volume of the reacted alkaline components of a cement stone are offered. High-quality and quantitative changes in a pore space, which are irrespective of density and the relative molecular mass of reaction products are described. Besides, movement and distribution of gaseous products of reaction in volumes of a cement stone are simulated. Reasonable integrated dependences of influence of aggressive environment on various types of concrete surfaces are given. The methods of corrosion control offered in article allow substantially to lower or absolutely to exclude adverse effect of hostile environment on concrete and reinforced concrete structures already at a stage of selection of composition of concrete mix. In this case service life of concrete and reinforced concrete structures will increase. © 2016 Growing Science Ltd. All rights reserved.

Thermomechanical transient analysis of a thick-hollow FGM cylinder

Abstract: © 2016 Growing Science Ltd. All rights reserved.

Determination of fracture parameters for a bi-material center cracked plate subjected to biaxial loading using FEOD method

Abstract: Article history: Received 6 October, 2015 Accepted 27 February2016 Available online 27 February 2016 Fracture parameters of a bi-material plate containing a cener crack and subjected to biaxial tensile loading was calculated numerically. Based on the crack tip stress field obtained numerically in a bi-material joint and using the finite element over deterministic (FEOD) method, the stress intensity factors (KI and KII) and also non-singular T-stress terms, were determined for different material properties and biaxial loading cases. Due to asymmetry of loading and material properties in the investigated dissimilar plate, the center crack experinces mixed mode I/II fracture in general. By increasing the bi-material constant value, which shows the difference between the mechanical properties of two materials, the amplitude of stress intensity factor decreases. The obtained results from this method were in good agreement with the displacment field method prevousiuly reported by other researchers. © 2016 Growing Science Ltd. All rights reserved.

Fracture of underwater notched structures

Abstract: Article history: Received 6 September, 2015 Accepted 20 December 2015 Available online 21 December 2015 Underwater structures are subjected to hydrostatic pressure during their service life. Sharp Vnotched components can be seen as a part of many underwater structures. For example, welded components, machined parts, gears, screws and bolts are among the well-known elements that contain sharp V-notches. The notch tip is a likely zone for initiation of cracks due to high stress/ strain concentration. The reliability analysis of the V-notched components requires a good understanding of stress/ strain distribution near the notch tip. The fracture initiation of the Vnotched components can be controlled by the tangential strain field near the notch tip. The tangential strain distribution and fracture initiation conditions are studied in this paper for notched components subjected to hydrostatic pressure. The effect of each tangential strain term on fracture initiation angle as well as tangential strain distribution around the notch tip is investigated using finite element simulation of a V-notched semi-circular specimen. It is shown that not only the singular terms, but also the “constants train field” significantly influence on tangential strain distribution and fracture initiation angle around the notch tip. The results of this paper can be used for standardization of the fracture in underwater structures containing V-notched components. © 2016 Growing Science Ltd. All rights reserved.

Exact solution for whirling analysis of axial-loaded Timoshenko rotor using basic functions

Abstract: A B S T R A C T In this paper, an analytical solution for whirling analysis of axial-loaded Timoshenko rotor is presented and corresponding basic functions are derived. The set of governing equations for whirling analysis of the rotor consists of four coupled partial differential equations; using complex displacements, these equations can be reduced to two coupled partial differential equations. The versatility of the proposed solution is confirmed using published results and the effect of angular velocity of spin, axial load, slenderness and Poisson's ratio on the natural frequencies of the rotor are investigated.

Effect of fiber volume fraction in the tensile properties of renewable Diss fiber /polyester composite

Abstract: This paper presents a novel composite material produced by a natural reinforcement subjected to tensile test. The used reinforcement is made of Diss fibers. The Diss (Ampelodesma mauritanica) is a Mediterranean wild plant. This fiber is characterized in tensile according to ASTM standard. The results obtained show that the fiber Young’s modulus and the stress at break were very interesting and were similar to those obtained for some natural fibers such as sisal fiber. The composite was developed to study by three differing volume fractions of 20%, 30 % and 40 %.

A new method for evaluation nominal coefficient of friction and frictional forces in turning and inserts characterization using cutting forces profiles

Abstract: Article history: Received 6 April, 2015 Accepted 19 October 2015 Available online 28 October 2015 Serviceable engineering components not only rely on their bulk material properties but also on the design and the characteristics of their surface. These characteristics influence directly the surface quality of the machined products. In terms of surface roughness, the influence of the tool material can be also caused by its tribological properties, i.e. a contact behavior between cutting tool and workpiece. This study presents a formulation of the nominal’s coefficient and friction forces generated in machining between workpiece and cutting tool using cutting force profiles. The obtained equations led to the evaluation of coefficient, frictional forces and cutting inserts characterization in terms of better surface finish and lowest frictional forces. Indeed, results show that the contact between cutting tool and workpiece depends on the materials cutting tool nature, and that the cutting tool type can influences the surface roughness of the machined surface. © 2016 Growing Science Ltd. All rights reserved.

DQM modeling of rectangular plate resting on two parameter foundation

Abstract: Article history: Received 6 April, 2015 Accepted 10 October 2015 Available online 11 October 2015 This paper presents two parameter foundation models for free vibration analysis of nonhomogeneous orthotropic rectangular plate resting on elastic foundation whose concept is extensively used in engineering practice. Following Levy approach i.e. the two parallel edges are simply supported, the fourth order differential equation governing the motion of such plates of non-linear varying thickness in one direction has been solved by using an efficient and rapid convergent numerical approximation technique that is called differential quadrature method (DQM). Appropriate boundary conditions accompany the differential quadrature method to transform the resulting differential equation into an eigenvalue problem. The effects of thickness variation, foundation parameters and other plate parameters with boundary conditions on frequency are examined. The numerical results show that the method converges significantly irrespective of parameters involved. © 2016 Growing Science Ltd. All rights reserved.

An effective combination of finite element and differential quadrature method for analyzing of plates partially resting on elastic foundation

Abstract: Article history: Received 6 March, 2016 Accepted 23 June 2016 Available online 23 June 2016 This paper is concerned with the vibration and stability analysis of thick rectangular plates resting on elastic foundation, which is distributed over the particular area of the plate. A twoparameter (Pasternak) model is considered to describe the elastic foundation. The eigenvalue problem in 3-D domain is numerically solved by a combination of the finite element and differential quadrature method (DQM). The energy principle is employed to derive the governing equations in the framework of three-dimensional, linear and small strain theory of elasticity. The in-plane domain of the problem is discretized using two-dimensional finite elements and spatial derivatives of equations in the thickness direction are discretized in strongform using DQM. As a first endeavor, the mixed FE-DQ method has been employed for 3-D buckling and free vibration analysis of rectangular thick plates partially supported by an elastic foundation. The accuracy of obtained results is validated by comparing to the few analytical solutions in the literature. © 2016 Growing Science Ltd. All rights reserved.

Numerical analysis of reinforced concrete beams containing bending and shear opening and strengthened with FRP sheet

Abstract: Article history: Received 6 September, 2015 Accepted 18 January 2016 Available online 18 January 2016 Various methods are available to reinforce concrete members and structures. Wrapping the concrete beams with composite sheets is one of the suggested methods for increasing the load bearing capacity of concrete beams and specially those containing opening. In this paper, the influence of using two composite sheets reinforced with carbon (CFRP) and glass (GFRP) is studied on increasing the strength of concrete beams having opening. A number of concrete beams with and without openings were modeled in ANSYS and using the nonlinear analyses, the initial cracking load, ultimate failure load, cracking pattern and deflection were determined numerically for each beam. Different wrapping schemes were examined for increasing the load bearing capacity of the opening section and it was concluded that wrapping from both inside and exterior of opening with the mentioned composite patches provide the most enhancement in the opening zone. Also the CFRP patch showed better performance in comparison with the GFRP wrapping. © 2016 Growing Science Ltd. All rights reserved.

Influence of machining parameters on surface roughness and dry friction

Abstract: Article history: Received 6 October, 2015 Accepted 7 March 2016 Available online 8 March 2016 Dry friction depends on the surface topography which, in turn, is governed by machining parameters in addition to several other factors,. Therefore, in order to establish a qualitative relationship among these factors, the surface roughness and coefficient of static friction are measured for specimens machined on lathe and shaper machines with different values of machining parameters. For the case of lathe, the measured Ra value is found to increase with increase in feed rate and depth of cut, whereas, a marginal decrease is observed with increasing spindle speed. Similar results with respect to cutting speed have been obtained for the case of shaper machine. On the other hand, the coefficient of static friction, measured on steel substrate using inclined plane method, is found to decrease with increasing Ra values for both the specimen types. © 2016 Growing Science Ltd. All rights reserved.

Guillotine side trimming shear machine: A case study of plate mill in Bhilai steel plant

Abstract: Article history: Received 6 October, 2015 Accepted 23 April 2016 Available online 24 April 2016 Double-sided trimming shear machine is used for longitudinal both–sided trimming of steel plates and simultaneous scraping of trimmed edges at specific length. Side trimming shear (STS) executes the most vital role in increasing the productivity of plate mill and due to its feature, efficiency of plate mill division is enormously increases. In general, frequency of the occurrence of breakdown in STS machine is a most challenging task when STS performs side trimming and scrap cutting machining process. Bhilai Steel Plant (Steel Authority of India at Bhilai) in India is continuously facing a problem due to breakdown of STS machine. The use of separate knife for side trimming and scrap cutting reduces the possibility of scrap jamming which is a major reason for breakdown of STS machine. Researchers and practitioners also suggest the use of arc guillotine shear for side trimming and straight guillotine shear for scrap cutting for minimizing the breakdown in STS machine. The aim of this study is to describe the problems faced by the steel industry as well as the necessary steps which should be taken for improvement of the productivity of STS machine and also it has made contribution to Bhilai Steel Plant by its growth and prosperity. The methodology of study is purely qualitative and the results point out the problems, its implications, steps taken to improve the overall productivity of Bhilai steel plant. © 2016 Growing Science Ltd. All rights reserved.

Rayleigh wave in a micropolar thermoelastic medium without energy dissipation

Abstract: Article history: Received 6 April, 2015 Accepted 19 October 2015 Available online 19 October 2015 The linear governing equations of a micropolar thermoelastic medium without energy dissipation are solved for surface wave solutions. The appropriate solutions satisfying the radiation conditions are applied to the required boundary conditions at the free surface of the half-space of the medium. A frequency equation is obtained for Rayleigh wave in the medium. The non-dimensional speed of the propagation of Rayleigh wave is computed for a specific model of the material and are shown graphically against frequency and non-dimensional parameter. © 2016 Growing Science Ltd. All rights reserved.

A train bearing fault detection and diagnosis using acoustic emission

Abstract: Article history: Received 6 September, 2015 Accepted 9 December 2015 Available online 9 December 2015 This paper provides a method of acoustic emission (AE) technique to detect a train bearing fault of tapered bearing unit (TBU). An approach is to utilize acoustic emission signals which were captured from piezoelectric transducer and processed using Fourier transform. The transformed signals may contain unique characteristic features relating to the various types of bearing faults. The experiments on different operating conditions were investigated and they corresponded to (a) a normal bearing and (b) outer race defect bearing. The result is promising for faulty bearing identification and discrimination between different bearing conditions. © 2016 Growing Science Ltd. All rights reserved.

Feature extraction and optimized support vector machine for severity fault diagnosis in ball bearing

Abstract: In this paper, a method for severity fault diagnosis of ball bearings is presented. The method is based on wavelet packet transform (WPT), statistical parameters, principal component analysis (PCA) and support vector machine (SVM). The key to bearing faults diagnosis is features extraction. Hence, the proposed technique consists of preprocessing the bearing fault vibration signal using statistical parameters and energy obtained through the application of Db8- WPT at the third level of decomposition. After feature extraction from vibration signal, PCA is employed for dimensionality reduction. Finally, particle swarm optimization with passive congregation-based support vector machine is used to classify seven kinds of bearing faults. The classification results indicate the effectiveness of the proposed method for severity faults diagnosis in ball bearings.

Three dimensional viscoelastic medium under thermal shock

Abstract: Article history: Received 6 March, 2016 Accepted 23 June 2016 Available online 23 June 2016 This article deals with the thermoelastic interaction in a three-dimensional homogeneous and isotropic viscoelastic medium under the Dual-phase-lag model of generalized thermoelasticity. The resulting non-dimensional coupled equations are applied to a specific problem of a halfspace whose surface is traction-free and is subjected to a time-dependent thermal shock. The analytical expressions for the displacement components, stress, temperature and strain are obtained in the physical domain by employing normal mode analysis. These expressions are also calculated for a copper-like material and have been depicted graphically. Discussions have been made to highlight the effect of viscosity on the studied field. The phenomenon of a finite speed of propagation is observed for each field. Also, if the effect of viscosity is neglected, the results agree with the existing literature. © 2016 Growing Science Ltd. All rights reserved.

Force transducers – A review of design and metrological issues

Abstract: Article history: Received 6 September, 2015 Accepted 4 December 2015 Available online 4 December 2015 The present work reports the retrospective investigation of force transducers widely used for force measurement related applications in variety of areas. The paper discusses the salient features of different types of force transducers along with their design and metrological features. The force transducers are covered from the analogue type to modern force transducers. The paper attempts to discuss the limitations of the different types of force transducers. © 2016 Growing Science Ltd. All rights reserved.

Numerical study of shear wall behavior coupled with HPFRCC beam and diagonal reinforcements

Abstract: Article history: Received 6 September, 2015 Accepted 20 December 2015 Available online 21 December 2015 High performance fiber-reinforced cementitious composites (HPFRCC) are aggregates like cement grout with fine grains and fibers which can be used in many cases like seismic improvement of building components. One of these building components is connecting beam in coupled shear wall which can increase plasticity and energy absorption. In this paper nonlinear finite element model of coupled beam containing HPFRCC is analyzed and the influence diagonal reinforcement is investigated on cracking patterns, stress contours and hysteresis diagrams of shear wall. It was observed that diagonal reinforcements play significant role in shear load bearing capacity of shear wall coupled with HPFRCC beam. © 2016 Growing Science Ltd. All rights reserved.

Leak detection and localization using acoustic emission technique

Abstract: Article history: Received 6 April, 2015 Accepted 10 October 2015 Available online 11 October 2015 This article provides a method of acoustic emission (AE) technique to detect leakage in pipeline and locate the position of the leakage. The AE sensor is made of piezoelectric effect transducer to pick up the acoustic emission signal which is generated from the turbulent flow at the leak position. The signal conditioning unit is used to enhanced and eliminate the background noise from the leak location sources. The main acoustic emission processing unit is used to acquire and process the extracted AE characteristic parameters from preprocessing waveform. The leak pipeline is simulated by drilling the hole and plugged with M8 screw at different locations. The results show that the proposed AE method can detect and locate simultaneous leak condition in pipeline with promising results. © 2016 Growing Science Ltd. All rights reserved.

High-speed thermal-cycle processing of low-carbon steel in the initially hardened and initially cold-deformed condition

Abstract: Article history: Received 6 October, 2015 Accepted 27 January 2016 Available online 27 January 2016 The article is concerned with the research of the processes of formation of the structure and properties of systemically alloyed low carbon steel 10H3G3MF in initially hardened and initially cold-deformed condition at high speed thermal-cycle processing (TCP). Metallographic, dilatometric and fractographic analysis, transmission electronic microscopy and uniaxial tensile test and impact test (salt spray chamber) are used as the research methods. It is shown that the maximum fine crushing of grain structure of austenite to 1 micron with high speed TCP of the researched steel in initially cold-deformed condition occurs at the first cycle of heating to 900 ° C, at the same time nanostructural condition of martensite is realized with an average size of stick in the plane of the foil of 60 ± 10 nm, which results in a substantial increase of complex of mechanical properties. It was found that in all studied modes of high speed TCP the α → γ-conversion with heating in the inter-critical temperature range consists of three stages. © 2016 Growing Science Ltd. All rights reserved.

Aggrandizing and analysis of the adaptability of photovoltaic panels

Abstract: Article history: Received 6 September, 2015 Accepted 4 December 2015 Available online 4 December 2015 The use of solar energy has been adduced as an alternative way for generating electricity. This electricity is generated by solar panel but as temperature increases efficiency of panel decreases too. The main objective of this research paper is to minimize the use of the amount of water, electrical energy and required time needed for cooling of a solar panel. This paper discusses a new approach by acquiring water as a coolant for accomplishing Photovoltaic panels at their moderate temperature and limits it from overheating. It is the cheapest method to enhance the efficiency of the Photovoltaic panel in developing countries like India. This paper also analyses the material used in increasing the efficiency of PV panel. © 2016 Growing Science Ltd. All rights reserved.

Introducing resilience factor in the structure as a new control coefficient

Abstract: Article history: Received 6 March, 2016 Accepted 27 June 2016 Available online 28 June 2016 When a structure is influenced by the earthquake external force, some energy imposed to the structure is dissipated and remained energy causes structure displacements. Dissipated energy in the structure depends on the type of structure and its optimal engineering design. In any typical structure, the type of connections, stiffness of structure, dampers, place of windfall and damper and other factors play significant role in the amount of dissipated energy. This article introduces a new resilience factor which is a function of energy dissipation factors of input seismic energy. Mathematical equations are presented for this factor and its limits are determined for different periods. The applicability of the proposed factor is also investigated for two typical structural examples. © 2016 Growing Science Ltd. All rights reserved.

Finite element analysis of out-of-plane compressive properties of a honeycomb structures with hexagonal topology fabricated by the kirigami technique

Abstract: Article history: Received 6 September, 2015 Accepted 12 January 2016 Available online 14 January 2016 This work illustrates the manufacturing of the honeycomb hexagonal topology structures by the kirigami technical, and the compressive testing of this specimen. The cellular configuration is simulated using a series of finite element models representing fullscale. The models are benchmarked against experimental results from pure compression tests. Finite element models of the honeycomb assemblies under compressive loading have been developed using nonlinear shell elements from an ANSYS code. Good agreement is observed between numerical nonlinear simulations and the experimental results. © 2016 Growing Science Ltd. All rights reserved.