A Parametric Study on Failure of Pin-Loaded Unidirectional-Woven Composite Joints

2013 ◽  
Author(s):  
O. Aluko
Keyword(s):  
Experimental Data ◽  
Friction Coefficient ◽  
Parametric Study ◽  
Failure Load ◽  
Characteristic Curve ◽  
Experimental Tests ◽  
Composite Joints ◽  
Woven Composite ◽  
Curve Model ◽  
Stress Functions

An analysis was performed to predict the failure load of unidirectional and woven pinned loaded composite joints using the characteristic curve model. The characteristic dimensions used to determine the characteristic curve were evaluated from stress functions without experimental tests. A parametric study was carried out for different coefficient of friction ranging between 0 and 0.15 to evaluate the effect of friction on joints failure using Tsai-Wu failure criterion along the characteristic curve. A comparison of analytical results with the available experimental data showed that the friction coefficient of 0.05 generally gave the best prediction for the joint configurations evaluated.

A Soil Water Characteristic Curve Model Considering Urea Concentration

2013 ◽  
Vol 798-799 ◽  
pp. 157-160
Author(s):  
You Le Wang ◽  
Dong Fang Tian ◽  
Gai Qing Dai ◽  
Yao Ruan ◽  
Lang Tian
Keyword(s):  
Experimental Data ◽  
Water Content ◽  
Soil Water ◽  
Exponential Function ◽  
Characteristic Curve ◽  
Urea Concentration ◽  
Exponential Functions ◽  
Valuable Data ◽  
Soil Water Characteristic Curve ◽  
Curve Model

A new soil water characteristic curve (SWCC) model considering urea concentration is presented in the paper. Two assumptions are used to obtain the model. One is SWCC which could be described by exponential functions in the experiments. Another is relationship between the parameters of exponential functions and urea concentration which is linear based on experimental data. In the research, we have carried out some experiments of SWCC and obtained some valuable data which could affect urea concentration. By using linear fitting, an exponential function between water content and suction and urea concentration is established.

scholarly journals Mechanical Response and Damage of Woven Composite Materials Reinforced with Fique

2018 ◽  
Vol 774 ◽  
pp. 143-148 ◽  
Author(s):  
Octavio Andrés González-Estrada ◽  
Germán Díaz ◽  
Jabid E. Quiroga Mendez
Keyword(s):  
Experimental Data ◽  
Mechanical Behaviour ◽  
Structural Engineering ◽  
Mechanical Response ◽  
Experimental Tests ◽  
Woven Composites ◽  
Reinforced Composites ◽  
Woven Composite ◽  
The Matrix ◽  
Voxel Model

In this paper, we present the experimental and numerical modelling for the mechanical behaviour of woven composites reinforced with fique (furcraeaselloa) fibre, for different fique fibre woven configurations embed in an R744 epoxy matrix. The woven configurations are taken from commercial models and their mechanical properties validated by experimental data. We perform experimental tests using ASTM D3039 for the tensile response. We obtain values for Young’s modulus, ultimate strength, and deformation of unidirectional and woven reinforced composites. Scanning electron microscopy (SEM) is used for the fractographic analysis of the reinforced specimens. For the numerical model of the woven composite, we use the Texgen software to define the finite element voxel model and to estimate orthotropic mechanical parameters. Then, we determine the equivalent elastic properties of the composite, according to the materials and the fibre-matrix relations. We compare and validate the numerical results with the experimental data. We obtain stress and strain fields for the yarns and the matrix. The objective of this work is to establish a baseline of the mechanical behaviour of these natural reinforced composites to propose applications for structural engineering.

Bearing Strength Analysis of Pin-Loaded Elliptical Holes in Laminated Composite Joints

2011 ◽  
Author(s):  
O. Aluko ◽  
H. A. Whitworth
Keyword(s):  
Characteristic Curve ◽  
Laminated Composite ◽  
Complex Stress ◽  
Strength Analysis ◽  
Orthotropic Plates ◽  
Bearing Strength ◽  
Mode Of Failure ◽  
Curve Model ◽  
Stress Functions ◽  
Elliptical Holes

An analysis was performed to predict bearing strength and mode of failure of pin loaded orthotropic plates with elliptic holes of varying sizes using two dimensional stress analyses and a characteristic curve model. The stresses required to analyze joint failure were obtained by utilizing complex stress functions that were determined from assumed displacement expressions that satisfy the boundary conditions around the hole. Three different joint geometries with major-to-minor diameter ratios ranging from 1 to 5 were evaluated and the analysis revealed that the joint strength was found to vary with increasing major-to-minor diameter ratios. The material properties of graphite/epoxy laminates were used in this investigation.

Determination and Compare Analysis for Soil Water Characteristic Curve Model in Planting Soil in Saline Region of Tianjin

2010 ◽  
Vol 12 (3) ◽  
pp. 336-341
Author(s):  
Fei CAI ◽  
Xiaohou SHAO ◽  
Zhenyu WANG ◽  
Mingyong HUANG ◽  
Yaming ZHAI ◽  
...  
Keyword(s):  
Soil Water ◽  
Characteristic Curve ◽  
Soil Water Characteristic Curve ◽  
Curve Model ◽  
Compare Analysis

scholarly journals Experimental Methods for Measuring the Viscous Friction Coefficient in Hydraulic Spool Valves

2021 ◽  
Vol 13 (13) ◽  
pp. 7174
Author(s):  
Massimo Rundo ◽  
Paolo Casoli ◽  
Antonio Lettini
Keyword(s):  
Friction Coefficient ◽  
Viscous Friction ◽  
Experimental Tests ◽  
Experimental Methods ◽  
Displacement Transducer ◽  
A Posteriori ◽  
Displacement Control ◽  
Spool Valves ◽  
The University ◽  
Good Agreement

In hydraulic components, nonlinearities are responsible for critical behaviors that make it difficult to realize a reliable mathematical model for numerical simulation. With particular reference to hydraulic spool valves, the viscous friction coefficient between the sliding and the fixed body is an unknown parameter that is normally set a posteriori in order to obtain a good agreement with the experimental data. In this paper, two different methodologies to characterize experimentally the viscous friction coefficient in a hydraulic component with spool are presented. The two approaches are significantly different and are both based on experimental tests; they were developed in two distinct laboratories in different periods of time and applied to the same flow compensator of a pump displacement control. One of the procedures was carried out at the Fluid Power Research Laboratory of the Politecnico di Torino, while the other approach was developed at the University of Parma. Both the proposed methods reached similar outcomes; moreover, neither method requires the installation of a spool displacement transducer that can significantly affect the results.

A New Dynamic Wettability-Alteration Model for Oil-Wet Cores During Surfactant-Solution Imbibition

SPE Journal ◽  
2013 ◽  
Vol 18 (05) ◽  
pp. 818-828 ◽  
Author(s):  
M. Hosein Kalaei ◽  
Don W. Green ◽  
G. Paul Willhite
Keyword(s):  
Experimental Data ◽  
Oil Recovery ◽  
History Matching ◽  
Mechanistic Model ◽  
Surfactant Solution ◽  
Experimental Tests ◽  
Quantitative Agreement ◽  
Wettability Alteration ◽  
Porous Rock ◽  
Surfactant Solutions

Summary Wettability modification of solid rocks with surfactants is an important process and has the potential to recover oil from reservoirs. When wettability is altered by use of surfactant solutions, capillary pressure, relative permeabilities, and residual oil saturations change wherever the porous rock is contacted by the surfactant. In this study, a mechanistic model is described in which wettability alteration is simulated by a new empirical correlation of the contact angle with surfactant concentration developed from experimental data. This model was tested against results from experimental tests in which oil was displaced from oil-wet cores by imbibition of surfactant solutions. Quantitative agreement between the simulation results of oil displacement and experimental data from the literature was obtained. Simulation of the imbibition of surfactant solution in laboratory-scale cores with the new model demonstrated that wettability alteration is a dynamic process, which plays a significant role in history matching and prediction of oil recovery from oil-wet porous media. In these simulations, the gravity force was the primary cause of the surfactant-solution invasion of the core that changed the rock wettability toward a less oil-wet state.

Turbulence Model Influence on Numerical Investigation of Transonic Axial Compressor Rotor

2011 ◽  
Vol 308-310 ◽  
pp. 1519-1522
Author(s):  
Fang Xie ◽  
Chang Jiang Liu ◽  
You Jun Wang
Keyword(s):  
Experimental Data ◽  
Numerical Investigation ◽  
Turbulence Model ◽  
Characteristic Curve ◽  
Axial Compressor ◽  
Internal Flow ◽  
Turbulent Model ◽  
Compressor Rotor ◽  
Transonic Axial Compressor ◽  
Point Forecast

Numerical method using HI and HOH meshing combined B - L turbulent model and S - A turbulent model separately based on the Rotor 37 compressor Rotor was applied to the steady flow. results on pressure characteristic curve, stall point forecast etc were compared with related experimental data. This paper discussed calculation precision influenced by the turbulence model and numerical computation grid. This numerical investigation was basis for subsequent compressor internal flow field study.

Rounded Fin Edge and Step Position Effects on Discharge Coefficient in Rotating Labyrinth Seals

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Andrea Rapisarda ◽  
Alessio Desando ◽  
Elena Campagnoli ◽  
Roberto Taurino
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Leading Edge ◽  
Experimental Tests ◽  
Velocity Profiles ◽  
Pollutant Emission ◽  
Leakage Flow ◽  
Labyrinth Seals ◽  
Position Effects ◽  
Impact Reduction

The design of modern aircrafts propulsion systems is strongly influenced by the important objective of environmental impact reduction. Through a great number of researches carried out in the last decades, significant improvements have been obtained in terms of lower fuel consumption and pollutant emission. Experimental tests are a necessary step to achieve new solutions that are more efficient than the current designs, even if during the preliminary design phase, a valid alternative to expensive experimental tests is the implementation of numerical models. The processing power of modern computers allows indeed the simulation of more complex and detailed phenomena than the past years. The present work focuses on the implementation of a numerical model for rotating stepped labyrinth seals installed in low-pressure turbines. These components are widely employed in sealing turbomachinery to reduce the leakage flow between rotating components. The numerical simulations were performed by using computational fluid dynamics (CFD) methodology, focusing on the leakage performances at different rotating speeds and inlet preswirl ratios. Investigations on velocity profiles into seal cavities were also carried out. To begin with, a smooth labyrinth seal model was validated by using the experimental data found in the literature. The numerical simulations were extended to the honeycomb labyrinth seals, with the validation performed on the velocity profiles. Then, the effects of two geometrical parameters, the rounded fin tip leading edge, and the step position were numerically investigated for both smooth and honeycomb labyrinth seals. The obtained results are generally in good agreement with the experimental data. The main effect found when the fin tip leading edge was rounded was a large increase in leakage flow, while the step position contribution to the flow path behavior is nonmonotone.

A transfer function of a soil water characteristic curve model for sands

2010 ◽  
pp. 453-459 ◽  
Author(s):  
Em_ke Imre ◽  
Kalman Rajkai ◽  
R Genovese ◽  
C Jommi
Keyword(s):  
Transfer Function ◽  
Soil Water ◽  
Characteristic Curve ◽  
Soil Water Characteristic Curve ◽  
Curve Model

scholarly journals EFFECT OF FRICTION ON VIBRATIONAL CHARACTERISTICS OF ROTOR SYSTEM DURING ROTOR-STATOR INTERACTION

2020 ◽  
pp. 22-31
Author(s):  
Anton Kurakin ◽  
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Friction Coefficient ◽  
Rotor System ◽  
Aluminum Bronze ◽  
Rotor Systems ◽  
Vibrational Characteristics ◽  
Rotor Stator Interaction ◽  
Intermediate Value ◽  
Impact Motion

Systems operation which include rotating elements in certain cases is associated with occurrence of contact between the rotating parts (rotor) and the stationary parts (stator). There were cases then rotor-stator interaction led to damage or to complete unit destruction. For this reason, rotor-stator interaction is one of the main problem of rotor systems exploitation. The main aim of the work is to gather detail data about effect of friction on vibrational characteristics of rotor system during rotor-stator interaction. In this article the experimental investigation method and experimental investigation of dynamic behavior of rotor during rotor-stator interaction is presented. The analysis of experimental data obtained during interaction between steel rotor and stator made of aluminum, bronze and PTFE is presented. All results with rotor-stator contact and without were compared by using Campbell diagrams, orbits and frequency responses. Analysis of experimental data shows that friction has strong effect on vibrational characteristics of rotor system during rotor-stator interaction. According to friction ratio three kinds of vibrational characteristics of rotor system are distinguished: forward slipping if friction coefficient is small, backward rolling if friction coefficient is big, vibratory impact motion if friction coefficient has intermediate value. Created experimental method and gathered data about rotor dynamics during rotor-stator contact can be used for verification and tuning of mathematical models.

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