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Evaluation of Intensity of Stress Singularity for 3D Dissimilar Material Joints Based on Mesh Free Method (Relationship between Interface Width and Intensity of Stress Singularity)
T. Kurahashi,
A. Ishikawa,
H. Koguchi
Issue:
Volume 1, Issue 2, June 2013
Pages:
28-33
Received:
9 April 2013
Published:
30 May 2013
Abstract: We present the intensity of stress singularity for 3D dissimilar material joints based on mesh free method. When load is applied to surface of the bonded structure, stress at vertex on interface drastically increases and it appears that this stress singularity occur delamination of the bonded structure. Intensity of stress singularity can be expressed by stress distribution and the intensity of stress singularity. Therefore, it is necessary to obtain the stress distribution precisely. In this study, we focus on the mesh free method for the computation of the stress distribution. When this method is applied to compute stress distribution, incompatible cell can be employed and geometrical data for a target structure can be simply prepared. To confirm the validity of the results of mesh free method, comparison of the intensity of stress singularity between the mesh free and the boundary element methods is carried out.
Abstract: We present the intensity of stress singularity for 3D dissimilar material joints based on mesh free method. When load is applied to surface of the bonded structure, stress at vertex on interface drastically increases and it appears that this stress singularity occur delamination of the bonded structure. Intensity of stress singularity can be expres...
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The Hydrodynamic Squeeze Film Lubrication of the Ankle Joint
Albert E. Yousif,
Ali Amer Al-allaq
Issue:
Volume 1, Issue 2, June 2013
Pages:
34-42
Received:
29 May 2013
Published:
20 June 2013
Abstract: The main aim of the study presented in this paper is to determine the characteristics of synovial fluid film region by modeling the human ankle joint to obtain an analytical expression for the pressure distribution, load carrying capacity, coefficient of friction and reduction of synovial film thickness with time of approach. Thus in order to reach a comprehensive analysis of the human ankle joint lubrication, variable behavior of synovial fluid during different time of joint activities and the influences of articular cartilage has to be taken into account. The behavior of the synovial fluid has been assumed to be isothermal, shear thinning and non- Newtonian couple stress fluid. The model of ankle joint has been taken geometrically and kinematically as a partial porous journal bearing under the action of hydrodynamic squeeze film lubrication. Typical geometrical and physical values of the ankle joint were acquired from measured values reported in literature. The problem of ankle joint lubrication has been solved numerically for various couple stress fluid parameters together with effect of varying the porosity of the articular cartilage. It has been shown , in the presence of porous articular cartilage, and by assuming the synovial fluid to be a non- Newtonian shear thinning couple stress fluid that the , pressure distribution, load carrying capacity, synovial film thickness with time of approach increased and a reduction coefficient of friction in the hydrodynamic squeeze action in the ankle joint resulted.
Abstract: The main aim of the study presented in this paper is to determine the characteristics of synovial fluid film region by modeling the human ankle joint to obtain an analytical expression for the pressure distribution, load carrying capacity, coefficient of friction and reduction of synovial film thickness with time of approach. Thus in order to reach...
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Performance Evaluation of Cymbal Hydrophones for Underwater Applications
C. Kannan,
R. Dhilsha,
P. M. Rajeshwari,
Shibu Jacob,
M. A. Atmanand
Issue:
Volume 1, Issue 2, June 2013
Pages:
43-48
Received:
20 May 2013
Published:
20 June 2013
Abstract: This paper reports the performance differences in the receiving sensitivity and band width of Class V flex tensional transducers (Cymbals) both in-air and in-water by varying the design parameters. Cymbal elements with device diameter 8mm and 13mm with optimum designs achieved using finite element software ATILA is presented. The in-air and underwater characteristics of such transducers are described in this paper. The performance evaluation of the transducers both in air and water are also reported in this paper. It has been established that the resonance frequency shifts towards higher side while increasing the cavity depth retaining the cap diameter fixed. However, there exists a tradeoff between the choice of sensitivity and optimum cavity depth. A maximum Receiving Sensitivity (RS) of -203 dB re 1V/µPa @ 1m is obtained analytically for a single element with 13mm diameter and a cavity depth of 600 micron with a band of 2-20 kHz. Also a wide band of 1-30kHz is achieved with 8mm cymbal element having the same cavity depth with a Receiving Sensitivity -202.84 dB re 1V/µPa @ 1m. Effect of encapsulation on the performance of cymbal transducers is studied and analytical results are in agreement with experimental results. There exist critical fabrication factors that affect the performance of these elements while fabricated in bulk quantities for an array. Reliable production procedure has been developed for manufacturing of cymbal elements and its arrays. A 1×3 array of 13mm diameter cymbal transducer has been fabricated and tested for in-air and in-water performances. The RS showed a maximum value of -178 dB re 1V/µPa @ 1m in a frequency range of 2-20 kHz with an in-house developed preamplifier having a gain of 20dB for a single element using brass as cap material. An array gain of nearly 6 dB is obtained when connected in series. The procedure adopted for the fabrication of Cymbal elements is critical for obtaining a flat hydrophone array response over a wide frequency range.
Abstract: This paper reports the performance differences in the receiving sensitivity and band width of Class V flex tensional transducers (Cymbals) both in-air and in-water by varying the design parameters. Cymbal elements with device diameter 8mm and 13mm with optimum designs achieved using finite element software ATILA is presented. The in-air and underwa...
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“Muechas”–Design and Construction of An Active Solar Dryer for Biological Materials
Radivoj M. Topić,
Nenad Lj. Ćuprić,
Milan R. Božović
Issue:
Volume 1, Issue 2, June 2013
Pages:
49-58
Received:
4 June 2013
Published:
20 June 2013
Abstract: This paper presents an original design and construction of a small scale, mobile, universal, ecological, chamber, active, dryer “MUECHAS” for drying medical and aromatic plants and non-timber forest products. The drying process uses only solar energy. The drying agent is a mixture of hot pure air and already used drying agent from the drying chamber exhaust. Pure air is heated in flat plate solar collectors and it is pulled by an electrical fan placed on the top of the drying chamber. The mobility of the collectors and dryer provides optimal utilization of sun energy throughout the day. PV modules, placed on the roof of the dryer, generate all necessary electric power for the fan, the control system and charge a set of accumulators during the day. Experimental results and kinetics of the drying process obtained by the solar dryer prototype are also given.
Abstract: This paper presents an original design and construction of a small scale, mobile, universal, ecological, chamber, active, dryer “MUECHAS” for drying medical and aromatic plants and non-timber forest products. The drying process uses only solar energy. The drying agent is a mixture of hot pure air and already used drying agent from the drying chambe...
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Detect Tool Breakage By Using Combination Neural Decision System & Anfis Tool Wear Predictor
Soheil Mohtaram,
Mohammad Amin Nikbakht
Issue:
Volume 1, Issue 2, June 2013
Pages:
59-63
Received:
23 May 2013
Published:
30 June 2013
Abstract: The original contribution of the research is the developed monitoring system that can detect tool breakage in real time by using a combination of neural decision system and ANFIS tool wear predictor. The ANFIS method uses the relationship between flank wear and the resultant cutting force to estimate tool wear. Therefore, the ANFIS method is used to extract the features of tool states from cutting force signals. A neural network is used in tool condition monitoring system (TCM) as a decision making system to discriminate different malfunction states from measured signal. A series of experiments were conducted to determine the relationship between flank wear and cutting force as well as cutting parameters. The forces were measured using a piezoelectric dynamometer and data acquisition system. Simultaneously flank wear at the cutting edge was monitored by using a tool maker’s microscope. The experimental force and wear data were utilized to train the developed simulation environment based on ANFIS modeling. By developed tool condition monitoring system (TCM) the machining process can be on-line monitored and stopped for tool change based on a pre-set tool-wear limit.
Abstract: The original contribution of the research is the developed monitoring system that can detect tool breakage in real time by using a combination of neural decision system and ANFIS tool wear predictor. The ANFIS method uses the relationship between flank wear and the resultant cutting force to estimate tool wear. Therefore, the ANFIS method is used t...
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