scholarly journals Experimental Investigation and Numerical Simulation of C-Shape Thin-Walled Steel Profile Joints

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 636
Author(s):  
George Taranu ◽  
Ionut-Ovidiu Toma
Keyword(s):  
Negative Impact ◽  
Strain Curve ◽  
Experimental Tests ◽  
Tensile Tests ◽  
Elastic Behavior ◽  
Experimental Program ◽  
Static Structure ◽  
Solid Models ◽  
Low Mass ◽  
Thin Walled

The versatility of steel, its high resistance in relation to its low mass, as well as the easily accessible technology in the context of using recyclable materials and the low negative impact on the environment represent important arguments in using thin-walled steel profiles to make structures for buildings with a low height regime. This paper presents the results of an experimental program that investigated the behavior of three types of joints in a T-shape form made of thin-walled steel profiles to make shear wall panels or truss beam floors. Due to the small dimensions of the C-profiles of 89 × 41 × 12 × 1 mm, and of the technology of their joining, manufacturers prefer the hinged connections of elements with self-drilling screws. The purpose of the research presented in this paper is to assess the maximum capacity of the joints, the elastic and post-elastic behavior until failure, and also the mechanisms failure. The types of joints analyzed are commonly used in the production of structural systems for houses. The experimental program, which consisted of testing 5 specimens for each type of joint in tension (shear on screws), showed different behavior in terms of load-displacement. The experimental, tested models were analyzed by finite element simulations in an ANSYS nonlinear static structure with 3D solid models. The materials were defined by a bilinear true stress–strain curve obtained after some experimental tensile tests of the steel. The results of the experimental tests showed that the main failure mechanism is a yielding of the holes where the screws were mounted and a shearing of the profile walls. Adding an additional screw on each side increases the capacity of the joints, but not until a yield loss is obtained. In conclusion, it is shown that the solution is suitable for a low level of loading in a static manner; however, additional studies are necessary in order to develop and verify other solutions, thus improving the strength of the connection.

scholarly journals A Novel Approach for the Detection of Geometric- and Weight-Related FSW Tool Wear Using Stripe Light Projection

2020 ◽  
Vol 4 (2) ◽  
pp. 60
Author(s):  
Michael Hasieber ◽  
Michael Grätzel ◽  
Jean Pierre Bergmann
Keyword(s):  
Wear Rate ◽  
Tool Wear ◽  
Weld Seam ◽  
Negative Impact ◽  
Experimental Tests ◽  
Tensile Tests ◽  
Industrial Applications ◽  
Robotic Welding ◽  
Friction Stir ◽  
Wide Range

Friction stir welding (FSW) has become an up-and-coming joining method with a wide range of industrial applications. Besides the unique weld seam properties, recent investigations have focused on the process-related tool wear of shoulder and probe, which can have detrimental economic and technological effects. This paper presents a systematic quantitative characterization of FSW tool wear using stripe light projection as a novel method to detect weight and form deviations of shoulder and probe. The investigations were carried out with a robotic welding setup in which AA-6060 T66 sheets, with a thickness of 8 mm, were joined by weld seams up to a total length of 80 m. During the experimental tests, geometrical deviations of the tool induced by wear were detected for varying weld seam lengths and different measuring points on the probe and shoulder. It was shown that wear depended on welding length which in turn caused significant deviations and weight losses on shoulder and probe. Furthermore, it was demonstrated that the wear on shoulder and probe can be considered separately. It was found that there is a progressive wear rate on the shoulder and a degressive wear rate on the probe depending on the weld seam length. To demonstrate the negative impact of tool wear on shoulder and probe after 80 m weld seam length, visual and metallographic inspections and tensile tests were carried out to detect resultant irregularities in the weld seam.

scholarly journals Experimental Validation of a Novel Thin-Walled Beam Prototype

2020 ◽  
Vol 22 (1) ◽  
pp. 7-24
Author(s):  
Hugo Miguel Silva ◽  
José Filipe Meireles ◽  
Jerzy Wojewoda
Keyword(s):  
Finite Element Analysis ◽  
Material Properties ◽  
Experimental Validation ◽  
Experimental Tests ◽  
Tensile Tests ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
Average Value ◽  
Thin Walled

AbstractIn this paper, an experimental validation of a novel beam prototype is performed. Tensile tests, both until rupture and on the elastic domain were done in order to determine the material properties. They were used then in Finite Element Analysis model built in ANSYS Mechanical APDL. Three experimental tests were done to the prototype, and, in order to minimize errors, the average value of the three tests determined, and compared with results obtained from the numerical model. It was shown that it was possible to manufacture the beam by the presented manufacturing methodology. An acceptable correlation between the numerical an experimental results was found.

scholarly journals Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cross Section ◽  
Negative Impact ◽  
Tensile Tests ◽  
Thermal Recovery ◽  
Bending Test ◽  
Small Scale ◽  
Spruce Wood ◽  
The Impact

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.

scholarly journals Tensile Behaviour of FRCM Composites for Strengthening of Masonry Structures—An Experimental Investigation

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3626
Author(s):  
Łukasz Hojdys ◽  
Piotr Krajewski
Keyword(s):  
Tensile Stress ◽  
Strain Curve ◽  
Tensile Tests ◽  
Tensile Failure ◽  
Tensile Behaviour ◽  
Masonry Structures ◽  
Stress Strain ◽  
Flexural Tensile Strength ◽  
Cracking Pattern ◽  
Direct Tensile

This paper presents the results of direct tensile tests performed on six different FRCM (fabric reinforced cementitious matrix) strengthening systems used for masonry structures. The emphasis was placed on the determination of the mechanical parameters of each tested system and a comparison of their tensile behaviour in terms of first crack stress, ultimate stress, ultimate strain, cracking pattern, failure mode and idealised tensile stress-strain curve. In addition to the basic mechanical tensile parameters, accidental load eccentricities, matrix tensile strengths, and matrix modules of elasticity were estimated. The results of the tests showed that the tensile behaviour of FRCM composites strongly depends on the parameters of the constituent materials (matrix and fabric). In the tests, tensile failure of reinforcement and fibre slippage within the matrix were observed. The presented research showed that the accidental eccentricities did not substantially affect the obtained results and that the more slender the specimen used, the more consistent the obtained results. The analysis based on a rule of mixtures showed that the direct tensile to flexural tensile strength ratio of the matrixes used in the test was 0.2 to 0.4. Finally, the tensile stress–strain relationship for the tested FRCMs was idealised by a bi- or tri-linear curve.

Design and testing of Modified Atmosphere Packaging of cow’s ricotta

2018 ◽  
Author(s):  
Sara Ugolotti ◽  
Giuseppe Vignali
Keyword(s):  
Shelf Life ◽  
Modified Atmosphere Packaging ◽  
Experimental Tests ◽  
Experimental Program ◽  
Human Consumption ◽  
Modified Atmosphere ◽  
Multilayer Material ◽  
Product Packaging ◽  
Special Instrument ◽  
Design And Testing

"The aim of this work is to evaluate the shelf life of cow’s ricotta under MAP (Modified Atmosphere Packaging). MAP is a packaging technique commonly used in the food industry in order to control the microbial growth. After the extraction of the air present in the headspace of the package, a mixture of CO2, O2 and N2 in different percentage is usually introduced before the packaging sealing. Based on these premises, a design of experimental tests has been created in order to evaluate the effect of each process parameters. To perform these test, it is also required the creation of thermoformed trays (made with a multilayer material using PET/EVOH/PE) in which the ricotta was inserted and packaged in a modified atmosphere. After the time intervals established in the experimental program, the analysis of the MAP was carried out using a special instrument (“Oxybaby” made by Witt SpA), able to measure the quantity of gas present in the headspace of the thermoformed trays. Then a statistical analysis of the obtained results was carried out. The results showed that after 10 days the product was edible for all types of atmosphere, but at 20 and, especially, at 30 days, even in the trays wrapped with CO2, the product was not acceptable for human consumption. One of the possible solutions, in order to lengthen the shelf life of cow’s ricotta, consists in the pre-sterilization of the trays before the product packaging with a solution of H2O2."

scholarly journals Stress-strain curve of concretes with recycled concrete aggregates: analysis of the NBR 8522 methodology

2017 ◽  
Vol 10 (3) ◽  
pp. 547-567 ◽  
Author(s):  
D. A. GUJEL ◽  
C. S. KAZMIERCZAK ◽  
J. R. MASUERO
Keyword(s):  
Test Procedure ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Load Test ◽  
Recycled Aggregates ◽  
Elastic Behavior ◽  
It Use ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Brazilian Standard

ABSTRACT This work analyses the methodology "A" (item A.4) employed by the Brazilian Standard ABNT 8522 (ABNT, 2008) for determining the stress-strain behavior of cylindrical specimens of concrete, presenting considerations about possible enhancements aiming it use for concretes with recycled aggregates with automatic test equipment. The methodology specified by the Brazilian Standard presents methodological issues that brings distortions in obtaining the stress-strain curve, as the use of a very limited number of sampling points and by inducing micro cracks and fluency in the elastic behavior of the material due to the use of steady stress levels in the test. The use of a base stress of 0.5 MPa is too low for modern high load test machines designed do high strength concrete test. The work presents a discussion over these subjects, and a proposal of a modified test procedure to avoid such situations.

scholarly journals Stiffness of Concrete-Filled Thin-Walled Steel Tubular Slender Columns

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alireza Bahrami ◽  
Ali Mahmoudi Kouhi
Keyword(s):  
Uniform Distribution ◽  
Experimental Tests ◽  
Simulation Method ◽  
Steel Tube ◽  
Initial Stiffness ◽  
Cross Sectional ◽  
Circular Column ◽  
Finite Element Software ◽  
Thin Walled ◽  
Slender Columns

Abstract Concrete-filled thin-walled steel tubular slender columns are studied in this paper to evaluate their stiffness. The slender columns have various steel tube thicknesses, length/diameter (width) ratios, and concrete compressive strengths. The columns are loaded by axial and eccentric loads. Two experimental tests of the slender and stub columns are described. Also, the finite element software ABAQUS is utilised to simulate and analyse the columns. The tested columns are simulated taking into account all their features in the tests to verify the simulation of the columns. The simulation results are compared with the tests results which reveal that good agreements exist between them. Thus, the proposed simulation method of the columns is verified. In order to assess the stiffness of the columns under different conditions, various load eccentricities (0 mm, 25 mm, and 50 mm), cross-sectional configurations (circular, rectangular, and square), and steel tube thicknesses (2 mm, 3.35 mm, and 5 mm) are adopted for the developed columns. The columns are simulated and analysed based on the verified simulation method considering the mentioned conditions. As a conclusion, the stiffness of the columns is generally reduced by the increase of the load eccentricity from 0 mm to 25 mm and 50 mm. Further, more uniform distribution of the stiffness is witnessed for the columns with lower eccentricities. In addition, the enhancement of the load eccentricity increased the reduction slope of the stiffness graph for the columns. Although the initial stiffness of the circular column is slightly lower than the rectangular and square columns, the stiffness has more uniform distribution which is preferred. Larger stiffness is achieved for the columns by increasing the steel tube thickness from 2 mm to 3.35 mm and 5 mm.

Experimental Investigations on Spot Welded Built-Up Cold-Formed Steel Beams

2018 ◽  
Vol 1146 ◽  
pp. 142-151
Author(s):  
Viorel Ungureanu ◽  
Ioan Both ◽  
Mircea Burca ◽  
Ştefan Benzar ◽  
Thai Hoang Nguyen ◽  
...  
Keyword(s):  
Spot Welding ◽  
Steel Sheet ◽  
Experimental Program ◽  
Experimental Investigations ◽  
Steel Beams ◽  
Technological Solution ◽  
Research Project ◽  
Steel Sheets ◽  
Cold Formed Steel ◽  
Thin Walled

Within the WELLFORMED research project, ongoing at the CEMSIG Research Center of the Politehnica University of Timisoara, a new technological solution was proposed for built-up beams made of corrugated steel sheets for the web and thin-walled cold-formed steel profiles for the flanges, connected by spot welding. The research project integrates an extensive experimental program on such beams, using full scale specimens, to demonstrate the feasibility of the proposed solutions and to assess their performance, followed by numerical simulations to characterize and optimize the connecting details. The present paper presents the results of a large experimental program, on small specimens subjected to shear, consisting of two or three layers of steel sheet connected by spot welding.

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