An Experimental Testing of Fillet Welded Specimens

2015 ◽  
Vol 752-753 ◽  
pp. 412-417 ◽  
Author(s):  
Martin Krejsa ◽  
Jiri Brozovsky ◽  
David Mikolasek ◽  
Premysl Parenica ◽  
Libor Zidek ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Stress Analysis ◽  
Numerical Models ◽  
Experimental Testing ◽  
Fem Analysis ◽  
Experimental Tests ◽  
Strength Characteristics ◽  
Fillet Welds ◽  
Commercial Software

The paper describes the experimental tests of steel bearing elements, which were aimed at obtaining material, geometric and strength characteristics of the fillet welds. Preparation of experiment consisted in defining of numerical models of tested samples using FEM analysis and the commercial software ANSYS. Data obtained from described experimental tests are necessary for further numerical modelling of stress analysis of steel structural supporting elements.

Analysis of Composite Shrinkage Stresses on 3D Premolar Models with Different Cavity Design Using Finite Element Method

2013 ◽  
Vol 586 ◽  
pp. 202-205 ◽  
Author(s):  
Milos Milosevic ◽  
Nenad Mitrovic ◽  
Vesna Miletić ◽  
Uroš Tatic ◽  
Andrea Ezdenci
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Models ◽  
Experimental Testing ◽  
Fem Analysis ◽  
Local Stress ◽  
Model Verification ◽  
Polymerization Shrinkage ◽  
Displacement Analysis ◽  
Element Method

Local polymerization stress occurs due to polymerization shrinkage of resin based composites adhesively bonded to tooth tissues. Shrinkage causes local displacements of cavity walls, with possible occurrence of micro-cracks in the enamel, dentin and/or material itself. In order to design a cavity for experimental testing of polymerization shrinkage of dental composites using 3D optical analysis, in this paper finite element method (FEM) was used to analyze numerical models with different cavity radiuses. 3D optical strain and displacement analysis of composite materials and cavity walls is limited by equipment sensitivity i.e. 0.01% for strain and 1 micron for displacement. This paper presents the development of 3D computer premolar models with varying cavity radiuses, and local stress, strain and displacement analysis using FEM. Model verification was performed by comparing obtained results with data from the scientific literature. Using the FEM analysis of local strains, displacements and stresses exerted on cavity walls, it was concluded that the model with 1 mm radius was optimal for experimental optical 3D displacement analysis.

Studies on Establishing a Methodology for Predicting the Riveted Joints Fatigue Durability in Aircraft Structures

2014 ◽  
Vol 1036 ◽  
pp. 668-673
Author(s):  
Roxana Nedelcu ◽  
Daniela Bartiș ◽  
Anca Lupaș ◽  
Constantin Ilie ◽  
Daniela Voicu
Keyword(s):  
Fatigue Crack ◽  
Numerical Models ◽  
Propagation Speed ◽  
Fem Analysis ◽  
Experimental Tests ◽  
Multiple Cracks ◽  
Technological Parameters ◽  
Riveted Joints ◽  
Physical Tests ◽  
The Moment

In this paper are described fatigue physical tests that were performed on a great number of riveted specimens with different constructive and technological parameters. Some of the purposes of the experimental tests, they were: determining the number of load cycles at which cracks by fatigue occurred, determining the moment of initiation, the location and propagation speed of the fatigue crack. For fatigue crack evolution study numerical models were designed. A simplified model for FEM analysis was proposed that reduced considerable the calculus effort and allows models for complex riveted joints. From the described experiments on specimens and numerical simulations there are some important conclusions regarding the fatigue phenomenon in riveted joints such as: important peculiarity of damage by multiple cracks is the cracks junction of adjacent rivet holes, which contributes, by jumping, to increase the degradation rate of assembly; the riveted joint model can be applied with good accuracy to estimate the durability of the structures inclusively to identify and prevent the cases of widespread fatigue damage.

MECHANICAL CHARACTERIZATION OF ANIMAL DERIVED GRAFTS FOR SURGICAL IMPLANTATION

2016 ◽  
Vol 16 (03) ◽  
pp. 1650023 ◽  
Author(s):  
PIERO GIOVANNI PAVAN ◽  
PAOLA PACHERA ◽  
SILVIA TODROS ◽  
CESARE TIENGO ◽  
ARTURO NICOLA NATALI
Keyword(s):  
Stress Relaxation ◽  
Constitutive Model ◽  
Relaxation Process ◽  
Mechanical Response ◽  
Numerical Models ◽  
Experimental Testing ◽  
Axial Stress ◽  
Experimental Tests ◽  
Tissue Samples

Bioprostheses obtained from animal models are often adopted in abdominal surgery for repair and reconstruction. The functionality of these prosthetic implants is related also to their mechanical characteristics that are analyzed here. This work illustrates a constitutive model to describe the short-term mechanical response of Permacol[Formula: see text] bioprostheses. Experimental tests were developed on tissue samples to highlight mechanical non-linear characteristics and viscoelastic phenomena. Uni-axial tensile tests were developed to evaluate the strength and strain stiffening. Incremental uni-axial stress relaxation tests were carried out at nominal strain ranging from 10% to 20% and to monitor the stress relaxation process up to 400[Formula: see text]s. The constitutive model effectively describes the mechanical behavior found in experimental testing. The mechanical response appears to be independent on the loading direction, showing that the tissue can be considered as isotropic. The viscoelastic response of the tissue shows a strong decay of the stress in the first seconds of the relaxation process. The investigation performed is aimed at a general characterization of the biomechanical response and addresses the development of numerical models to evaluate the biomechanical performance of the graft with surrounding host tissues.

Numerical Modelling of the Experimental Response of SRG Systems

2019 ◽  
Vol 817 ◽  
pp. 37-43
Author(s):  
Marialaura Malena ◽  
Marialuigia Sangirardi ◽  
Francesca Roscini ◽  
Gianmarco de Felice
Keyword(s):  
Numerical Modelling ◽  
Large Scale ◽  
Numerical Models ◽  
High Strength ◽  
Experimental Tests ◽  
Tensile Tests ◽  
Technical Committee ◽  
Structural Performance ◽  
Rilem Technical Committee ◽  
Test Procedures

Modern repairing and retrofitting methods for existing structures make use of composite materials, consisting of high strength textiles and a matrix, which can be either polymeric or inorganic. These kinds of techniques have been largely applied to masonry structures, since they significantly improve structural performance with a small increase of weight and a minimum invasiveness. However, the application of organic gluing agents on masonry has revealed some well-known drawbacks, which are almost all overcome resorting to inorganic matrixes, namely cement or lime mortars. An entire class of composites is thus identified as TRM (Textile Reinforced Mortars) or FRCM (Fibre Reinforced Cementitious Matrices). Among them, Steel Reinforced Grout (SRG) are characterized by Ultra High Tensile Strength Steel (UHTSS) cords embedded in mortar matrix and their use to improve the structural performance of existing historical masonry buildings is becoming more and more diffused. Qualification tests and acceptance criteria for SRG have just been defined. Nonetheless, numerical simulation of current available test procedures is mandatory to identify peculiar aspects of the response that at a following stage become an integral part of large scale models, when entire reinforced structures or portions need to be analysed. To this end, this work presents the numerical modelling of two different direct tensile tests on SRG systems: the Clamping-grip setup (RILEM Technical Committee 232-TDT 2016) and the Clevis-grip setup (ICC-ES AC434 2016). Numerical models able to replicate experimental tests and catch fundamental differences in their failure mechanisms are present

scholarly journals Development of Impact-Echo Multitransducer Device for Automated Concrete Homogeneity Assessment

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2144
Author(s):  
Bartłomiej Sawicki ◽  
Tomasz Piotrowski ◽  
Andrzej Garbacz
Keyword(s):  
Nondestructive Testing ◽  
Numerical Study ◽  
Numerical Models ◽  
Experimental Testing ◽  
Experimental Tests ◽  
Impact Echo ◽  
University Of Technology ◽  
Homogeneity Assessment

A combination of multiple nondestructive testing (NDT) methods speeds up the assessment of concrete and increases the precision. This is why the UIR-Scanner was developed at Warsaw University of Technology. The scanner uses an Impact-Echo (IE) method with a unique arrangement of multiple transducers. This paper presents the development of the IE module using numerical models validated with experimental testing. It was found that rectangular arrangement of four transducers with the impactor in the middle is optimal for quick scanning of area for faults and discontinuities, changing the method from punctual to volumetric. A numerical study of void detectability depending on its position with respect to the IE module is discussed as well. After confirmation of the findings of models using experimental tests, the module was implemented into the scanner.

scholarly journals A HUMAN CROWD EFFECT MODELLED BY THE DISCRETE-TIME FOURIER SERIES

2018 ◽  
pp. 139
Author(s):  
Miomir Jovanović ◽  
Goran Radoičić
Keyword(s):  
Discrete Time ◽  
Experimental Testing ◽  
Fem Analysis ◽  
Experimental Tests ◽  
Human Power ◽  
Equipment Safety ◽  
Crowd Effect ◽  
Transport Machine ◽  
Human Crowd ◽  
The Mathematical Model

Accidental actions caused by vibrations of supporting structures in mechanical systems represent the dynamic tasks of specific scientific and professional research in the field of human and equipment safety. This paper determines the mathematical model of physical excitation force created by   human power, based on the discrete-time Fourier transformation. For experimental verification of the model, we made a special platform for measuring bouncing force of people who create natural impulse oscillation. The paper shows the results of individual and group experimental testing of living force as the cause of accidents and dangerous effects on the structure. In the end, the excitation of the human operation of a malicious nature (heavy transport machine – crane) has been used to show the application of Fourier model to simulate one incident. For this purpose, the transient FEM analysis and the eigenvalues predetermined modal analysis are used. The paper is illustrated with photographs of experimental tests of dangerous human impulse in several working machines (objects).

scholarly journals Numerical Modelling and Validation of the Response of Masonry Infilled RC Frames Using Experimental Testing Results

Buildings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 182 ◽  
Author(s):  
Gianrocco Mucedero ◽  
Daniele Perrone ◽  
Emanuele Brunesi ◽  
Ricardo Monteiro
Keyword(s):  
Numerical Modelling ◽  
Experimental Testing ◽  
Experimental Tests ◽  
Masonry Infill ◽  
Masonry Infills ◽  
Rc Frames ◽  
Mediterranean Countries ◽  
Modelling Uncertainties ◽  
Infilled Rc Frames ◽  
Masonry Infilled Rc Frames

Reinforced concrete (RC) frame buildings with masonry infills represent one of the most common structural typologies worldwide. Although, in the past, masonry infills were frequently considered as non-structural elements and their interaction with the structure was neglected, earthquakes occurring over the last decades have demonstrated the important role of these elements in the seismic response of all RC-infilled building typologies. In this regard, the selection of the most suitable numerical modelling approaches to reproduce the hysteretic response of the masonry infills—and their interaction with the RC frames—is still an open issue. To deal with this issue, in this study, a macro-classification based on different available databases of experimental tests on infilled RC frames, is firstly proposed to understand the variability in the infill properties and the corresponding numerical modelling uncertainties. Five masonry infill types are selected as representative for the typical existing configurations in Italy and other Mediterranean countries. Three of those masonry infill types are then selected to carry out a more detailed analysis, namely their numerical modelling validation using experimental testing results, considering and comparing the main formulations available in the literature for the definition of the hysteretic behaviour of infills. From such a comparison, the model that minimizes the prediction error, according to specific features of the selected masonry infill, is identified for each masonry infill type.

scholarly journals Additively Manufactured Parts Made of a Polymer Material Used for the Experimental Verification of a Component of a High-Speed Machine with an Optimised Geometry—Preliminary Research

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 137
Author(s):  
Artur Andrearczyk ◽  
Bartlomiej Konieczny ◽  
Jerzy Sokołowski
Keyword(s):  
Polymer Material ◽  
High Speed ◽  
Numerical Models ◽  
Flow Analysis ◽  
Experimental Tests ◽  
Strength Analysis ◽  
Compressor Wheel ◽  
Operational Characteristics ◽  
3D Printed ◽  
Novel Method

This paper describes a novel method for the experimental validation of numerically optimised turbomachinery components. In the field of additive manufacturing, numerical models still need to be improved, especially with the experimental data. The paper presents the operational characteristics of a compressor wheel, measured during experimental research. The validation process included conducting a computational flow analysis and experimental tests of two compressor wheels: The aluminium wheel and the 3D printed wheel (made of a polymer material). The chosen manufacturing technology and the results obtained made it possible to determine the speed range in which the operation of the tested machine is stable. In addition, dynamic destructive tests were performed on the polymer disc and their results were compared with the results of the strength analysis. The tests were carried out at high rotational speeds (up to 120,000 rpm). The results of the research described above have proven the utility of this technology in the research and development of high-speed turbomachines operating at speeds up to 90,000 rpm. The research results obtained show that the technology used is suitable for multi-variant optimization of the tested machine part. This work has also contributed to the further development of numerical models.

On-Site Experimental Testing to Study the Vibration of Composite Floors

2014 ◽  
Vol 601 ◽  
pp. 231-234
Author(s):  
Cristian Lucian Ghindea ◽  
Dan Cretu ◽  
Monica Popescu ◽  
Radu Cruciat ◽  
Elena Tulei
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Testing ◽  
Concrete Slab ◽  
Human Perception ◽  
Experimental Tests ◽  
International Standards ◽  
Structural Element ◽  
Element Analysis ◽  
Floor Slabs ◽  
Composite Floors

As a general trend, in order to reduce material consumption or to reduce the mass of the structures, composite floor slabs solutions are used to achieve large spans floor slabs. This solutions led to floors sensitive to vibrations induced generally by human activities. As a verification of the design concepts of the composite floors, usually, it is recommended a further examination of the floor after completion by experimental tests. Although the experimental values of the dynamic response of the floor are uniquely determined, the processing can take two directions of evaluation. The first direction consist in determining the dynamic characteristics of the floor and their comparison with the design values. Another way that can be followed in the processing of the experimental results is to consider the human perception and comfort to the vibration on floors. The paper aims to present a case study on a composite floor, with steel beams and concrete slab, tested on-site. Both aspects of data processing are analyzed, in terms of the structural element, and in terms of the effect on human perception and comfort. Experimentally obtained values for the dynamic characteristics of the floor are compared with numerical values from finite element analysis, while the second type of characteristic values are compared with various human comfort threshold values found in international standards.

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