Delamination Buckling of FRP: Experimental Tests and Theoretical Model

2019 ◽  
pp. 753-766
Author(s):  
R. Capozucca ◽  
E. Magagnini ◽  
M. V. Vecchietti
Keyword(s):  
Theoretical Model ◽  
Experimental Tests ◽  
Delamination Buckling

scholarly journals Effect of Processing Parameters on the Dynamic Characteristic of Material Extrusion Additive Manufacturing Plates

2019 ◽  
Vol 9 (24) ◽  
pp. 5345
Author(s):  
Shijie Jiang ◽  
Yinfang Shi ◽  
Yannick Siyajeu ◽  
Ming Zhan ◽  
Chunyu Zhao ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Theoretical Model ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Experimental Tests ◽  
Processing Parameters ◽  
Combination Method ◽  
Mode Shapes ◽  
Material Extrusion ◽  
Function Combination

Material extrusion (ME), an additive manufacturing technique, can fabricate parts almost without geometrical limitations. With the growing application of ME parts, especially in actual working conditions, the dynamic characteristics are needed to be studied to accurately determine their reliability. This study provides an experimental validation of the theoretical model for predicting the dynamic characteristics of ME plates fabricated with three different key processing parameters, i.e., extrusion width, layer height and build direction. The model is set up based on the bidirectional beam function combination method, and a series of experimental tests are performed. It is found that different processing parameters result in the material properties of the samples to vary, thus leading to different dynamic characteristics. Through the comparison between predictions and measurements, it is shown that the influencing trend of the processing parameters is predicted precisely. The theoretical model gives reliable predictions in dynamic characteristics of ME plates. The natural frequency discrepancy is below 13.4%, and the predicted mode shapes are the same as the measured ones. This present work provides theoretical basis and technical support for further research in improving the dynamic performance of ME products, and helps extend the applications of this technique.

scholarly journals The dependence of heat transfer and friction on fin tip configuration

1987 ◽  
Vol 6 (3) ◽  
pp. 130-135
Author(s):  
L. J. C. Steyn ◽  
L. Pretorius ◽  
J. Visser
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Theoretical Model ◽  
Experimental Tests ◽  
Experimental Results ◽  
Tube Heat Exchanger ◽  
Friction Parameters ◽  
Annular Fins

The dependence of heat transfer and friction parameters on fin tip configuration is investigated. Experimental tests are performed on a double tube heat exchanger with transverse annular fins on the inner tube. Seven different fin configurations are investigated. A theoretical model is used to calculate the heat transfer and friction parameters from experimental results.

Column behaviour of cold-formed hollow structural steel shapes

1983 ◽  
Vol 10 (1) ◽  
pp. 125-141 ◽  
Author(s):  
T. A. Davison ◽  
P. C. Birkemoe
Keyword(s):  
Residual Stress ◽  
Theoretical Model ◽  
Structural Steel ◽  
Experimental Tests ◽  
Theoretical Research ◽  
Relative Importance ◽  
Cross Sectional ◽  
Heat Treated ◽  
Steel Shapes ◽  
Sectional Parameters

This paper presents a theoretical model describing the column behaviour of cold-formed heat-treated and non-heat-treated hollow structural steel (HSS) shapes. Member cross-sectional parameters in the form of residual stress and yield strength gradients as well as the member initial crookedness are incorporated into the column model. The parameter magnitudes used and their dispositions throughout the model are based on current experimental and theoretical research. The effect and relative importance of these parameters in determining the theoretical column strength is illustrated. The adequacy of the theoretical model in determining HSS column strength is shown by comparing it with the results of experimental tests conducted on full-sized HSS specimens. Finally, design curves for each of the HSS types studied are recommended.

Experimental and Numerical Simulation of Solar Still for the Production of Drinking Water in Desert Areas of Southern Algeria

2018 ◽  
Vol 26 (03) ◽  
pp. 1850024
Author(s):  
Mekki Zerouali ◽  
Fouad Khaldi ◽  
Zina Belkhiri
Keyword(s):  
Drinking Water ◽  
Theoretical Model ◽  
Saline Water ◽  
Water Film ◽  
Experimental Tests ◽  
Climatic Conditions ◽  
Reference Case ◽  
Simple Method ◽  
Solar Distillation ◽  
Desert Areas

Solar distillation is a simple method used for the production of drinking water from saline or brackish water. This method proposes a solution for the production of fresh water in arid and desert areas, where a large solar field is available and also the existence of underground sources of saline water. A solar distiller with a single basin and double slopes is theoretically examined. The theoretical model is based on the resolution of equations of heat and mass transfer dependent on time for glazing cover, water film and absorber basin. For validating the results of the theoretical model, a comparison with the experimental results was carried out. A series of experimental tests on a solar distiller with double slopes in the climatic conditions of Ouargla in Algeria were performed. The tests were carried out on 19th February 2009. The amount of water distilled was 2.7 liters, after a day’s work. The results show that the cooling of the glazing cover leads to increase in the amount of distilled water of about 17% in comparison with the reference case. In addition, we found a good agreement between the results of the theoretical model and the experimental data.

CLUSTER-IMPACT FUSION WITH CLUSTER BEAMS

1991 ◽  
Vol 06 (25) ◽  
pp. 2259-2270 ◽  
Author(s):  
Y. E. KIM ◽  
R. A. RICE ◽  
G. S. CHULICK ◽  
M. RABINOWITZ
Keyword(s):  
Theoretical Model ◽  
Experimental Tests ◽  
Rutherford Backscattering ◽  
Experimental Results ◽  
Heavy Atoms ◽  
Cluster Beams

Recent experiments in which beams of D 2 O clusters impact on deuterated targets have been observed to produce higher than expected deuterium-deuterium ( D - D ) fusion rates, whereas similar experiments with pure D clusters produced no observable D - D fusion. We present a theoretical model capable of explaining these apparently conflicting experimental results. Our calculations indicate that heavy atoms such as O in the cluster, and Ti, Zr, or C in the target are essential for obtaining high fusion rates and D energy enhancement by double Rutherford backscattering in the experiments as conducted. We predict the conditions for obtaining comparable yields from D , D 2 O , and H 2 O clusters and propose a set of experimental tests.

Theoretical and Experimental Analysis of a Cycloidal Speed Reducer

2007 ◽  
Author(s):  
Piermaria Davoli ◽  
Carlo Gorla ◽  
Francesco Rosa ◽  
Claudio Longoni ◽  
Franco Chiozzi ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Structural Characteristics ◽  
Design Procedure ◽  
Experimental Tests ◽  
Mechanical Efficiency ◽  
Industrial Applications ◽  
Fine Tuning ◽  
Design Parameters ◽  
Good Efficiency ◽  
Speed Reducer

Compared with common speed reducers, the cycloidal ones (also known as cycloid drives) cover a wider range of transmission ratios, have a higher load-carrying capacity, are smaller, exhibit a smoother running and a good efficiency. These characteristics make them attractive for industrial applications, especially for robotics applications, machine tools and linear axis positioning in assembly machinery. In this paper, a theoretical and experimental investigation on an innovative cycloidal speed reducer will be presented. The typical cycloid drive has a planet wheel, the profile of which is the inner offset of an epitrochoid, meshing with cylindrical rollers connected to the case. This reducer, on the contrary, has an external ring gear, the transverse profile of which is the external offset of an epitrochoid, and engages with the planet wheel by means of cylindrical rollers. This paper will investigate the structural characteristics and the kinematical principles of this type of reducer. A theoretical approach based on the envelope theory (following Litvin’s approach) will be developed and compared with a development of Blanche and Yang’s approach. Furthermore, a simplified procedure to calculate force distribution on cycloid drive elements, as well as its power losses and theoretical mechanical efficiency will be presented. The effects of design parameters on the values of the forces will be studied, for an optimal design of this type of reducer. The theoretical model will be then tuned using the results of tests on a specific rig. As a result of the experimental tests, the reducer mechanical efficiency dependency on speed and torque will be described. The aim of this work is to perform the fine tuning of a theoretical model in order to predict the operating behavior of the cycloid drive, and to improve its design procedure.

A New Mathematical Model of the Force in Pneumatic Tire-Snow Chain Systems

2006 ◽  
Author(s):  
Juan C. Botero ◽  
Massimiliano Gobbi ◽  
Giampiero Mastinu
Keyword(s):  
Mathematical Model ◽  
Theoretical Model ◽  
Traction Force ◽  
Experimental Tests ◽  
Safety Device ◽  
Transmitted Force ◽  
Basic Concepts ◽  
External Forces ◽  
The Mathematical Model ◽  
Made In

In this paper a new theoretical model to estimate the transmitted force in a snow-chain safety device is presented. Starting with a detailed analysis of the significant external forces acting on the system, the mathematical model is developed using some basic concepts of the contact mechanics theory. A MATLAB® code was developed in order to perform numerical simulations and experimental tests were carried out to validate the model. The results obtained show that for certain conditions of the driving surface and the tire's tread the force transmitted along the chain can be several times the longitudinal traction force applied to the tire itself. The importance of the interaction between the blocks on the tire and the chain segments is discussed. Some conclusions and recommendations are made in order to improve the design process of this kind of devices.

scholarly journals A Theoretical Model for Debonding Prediction in the RC Beams Externally Strengthened with Steel Strip and Inorganic Matrix

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4961
Author(s):  
Francesco Bencardino ◽  
Mattia Nisticò
Keyword(s):  
Theoretical Model ◽  
Steel Strip ◽  
Structural Response ◽  
Experimental Tests ◽  
Rc Beams ◽  
Matrix Interface ◽  
Differential Problem ◽  
Bond Slip ◽  
Strain Compatibility ◽  
Lap Shear

This paper shows a theoretical model for predicting the moment–curvature/load–deflection relationships and debonding failure of reinforced concrete (RC) beams externally strengthened with steel reinforced geopolymeric matrix (SRGM) or steel reinforced grout (SRG) systems. Force equilibrium and strain compatibility equations for a beam section divided into several segments are numerically solved using non-linear behaviour of concrete and internal steel bars. The deflection is then obtained from the flexural stiffness at a mid-span section. Considering the appropriate SRGM-concrete bond–slip law, calibrated on single-lap shear bond tests, both end and intermediate debonding failures are analysed. To predict the end debonding, an anchorage strength model is adopted. To predict intermediate debonding, at each pair of flexural cracks a shear stress limitation is placed at concrete–matrix interface and the differential problem is solved at steel strip–matrix interface. Based on the theoretical predictions, the comparisons with experimental data show that the proposed model can accurately predict the structural response of SRGM/SRG strengthened RC beams. It can be a useful tool for evaluating the behaviour of externally strengthened RC beams, avoiding experimental tests.

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