Fracture of underwater notched structures
, Pages: 43-52
M.M. Mirsayar and Behrouz Takabi PDF (650K)
Abstract: Underwater structures are subjected to hydrostatic pressure during their service life. Sharp V-notched 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 V-notched 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.
Keywords: Underwater structures, V-notch, Fracture, Hydrostatic pressure
Numerical study of shear wall behavior coupled with HPFRCC beam and diagonal reinforcements
, Pages: 53-62
Hamid Reza Ashrafi and Peyman Beiranvand PDF (650K)
Abstract: 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.
Keywords: Shear wall, Diagonal reinforcement, Nonlinear finite element, HPFRCC
A train bearing fault detection and diagnosis using acoustic emission
, Pages: 63-68
Tonphong Kaewkongka PDF (650K)
Abstract: 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.
Keywords: Acoustic emission, Bearing, Train, Detection, Diagnosis
Aggrandizing and analysis of the adaptability of photovoltaic panels
, Pages: 69-80
Anurag Ranjan, Ira Bhatnagar, Kavita Prajapati PDF (650K)
Abstract: 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.
Keywords: Alternative, Cooling, Overheating, Photovoltaic panel, Efficiency, Analyses
Force transducers – A review of design and metrological issues
, Pages: 81-90
Rajesh Kumar and S. Maji PDF (650K)
Abstract: 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.
Keywords: Force transducer, Uncertainty of measurement, MEMS, Strain gauge
Effect of fiber volume fraction in the tensile properties of renewable Diss fiber /polyester composite
, Pages: 91-96
Bouakba Mustapha, Issasfa Bahim, Boukatem Mourad and Belloufi Abderrahim PDF (650K)
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 %.
Keywords: Renewable fibers, Diss, Ampelodesma mauritanica, Natural fibers, Composite, Tensile properties
Exact solution for whirling analysis of axial-loaded Timoshenko rotor using basic functions
, Pages: 97-108
K. Torabi and H. Afshari PDF (650K)
Abstract: 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.
Keywords: Basic functions, Whirling analysis, Timoshenko rotor, Axial load
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