Laboratory and Numerical Analysis of Steel Cold-Formed Sigma Beams Retrofitted by Bonded CFRP Tapes—Extended Research

The presented research is a part of a broader study of strengthening methods closely associated with cold-formed sigma steel beams with tapes made of Carbon Fiber Reinforcement Polymer/Plastic (CFRP). The presented results are a continuation and extension of the tests described in previous work by the authors and refer to high-slenderness thin-walled steel sigma beams subjected to a significant large rotation. The main idea of this expanded study was to identify the effectiveness of CFRP tapes with respect to different locations, namely at a bottom-tensioned or upper-compressed flange. Six beams with a cross-section of an Σ140 × 70 × 2.5 profile by “Blachy Pruszyński” and made of S350GD steel with a span of L = 270 cm were tested in the four-point bending scheme. Two beams, taken as reference, were tested without reinforcement. The remaining beams were reinforced with the use of a 50-mm wide and 1.2-mm thick Sika CarboDur S512 CFRP tape, with two beams reinforced by placing the tape on the upper flange and two with tape located on the bottom flange. The CFRP tape was bonded directly to the beams (by SikaDur®-30 adhesive). Laboratory tests were aimed at determining the impact of the use of composite tapes on the limitation of displacements and deformations of thin-walled structures. In order to perform a precise measurement of displacement, which is, in the case of beams subjected to large rotations, a very difficult issue in itself, the Tritop system and two coupled lenses of the Aramis system were used. Electrofusion strain gauges were used to measure the deformation. In the next step, numerical models of the analyzed beams were developed in the Abaqus program. Good compliance of the results of laboratory tests and numerical analyses was achieved. The obtained results confirm the beneficial effect of the use of tapes (CFRP) on the reduction in displacements and deformations of steel cold-formed elements.

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Influence of boundary conditions in FEM model on structural behaviour of thin-walled steel beams strengthened by CFRP tapes

Budownictwo i Architektura ◽

10.35784/bud-arch.1671 ◽

2020 ◽

Vol 19 (2) ◽

pp. 073-086

Author(s):

Katarzyna Rzeszut ◽

Ilona Szewczak ◽

Patryk Rozylo

Keyword(s):

Boundary Conditions ◽

Laboratory Tests ◽

Numerical Models ◽

Load Capacity ◽

Steel Beams ◽

Structural Behaviour ◽

Fem Model ◽

Mesh Density ◽

Newton Raphson ◽

Thin Walled

The main aim of the study is verification and validation of FEM numerical model of beams made of thin-walled steel profiles retrofitted by CFRP tapes Sika CarboDur S. Validation is are carried out based on own laboratory tests conducted on “Blachy Pruszyński” S-type beams. The CFRP tape are bonded to the beam at compressed or tensioned flange. The most important part of this study is focused on investigation of boundary conditions influence in FEM model developed in Abaqus program. Moreover the numerical models are also tested in terms of different mesh density and types of finite elements. Numerical analyses are carried out using Newton-Raphson iterative method to solve non-linear equilibrium equation. In the paper special attention is paid to the evaluation of the possibility to increase the load capacity of the beams by appropriate localisation of CFRP tape.

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Laboratory and Numerical Analysis of Steel Cold-Formed Sigma Beams Retrofitted by Bonded CFRP Tapes

Materials ◽

10.3390/ma13194339 ◽

2020 ◽

Vol 13 (19) ◽

pp. 4339 ◽

Cited By ~ 2

Author(s):

Ilona Szewczak ◽

Katarzyna Rzeszut ◽

Patryk Rozylo ◽

Sylwester Samborski

Keyword(s):

Numerical Analysis ◽

Numerical Models ◽

Load Capacity ◽

Steel Structures ◽

Bottom Flange ◽

Building Structures ◽

Inner Surface ◽

Carbon Fibre Reinforced Polymer ◽

Thin Walled ◽

The Impact

In this paper, the retrofitting method of thin-walled, cold-formed sigma beams using bonded carbon fibre reinforced polymer (CFRP) tapes is proposed. The effectiveness of the presented strengthening method is investigated by the means of laboratory tests and numerical analysis conducted on simply supported, single-span beams made of 200 × 70 × 2 profile by “Blachy Pruszyński” subjected to a four-point bending scheme. Special attention is paid to the evaluation of possibility to increase the load capacity with simultaneous limitation of beams displacements by appropriate location of CFRP tapes. For this purpose, three beams were reinforced with CFRP tape placed on the inner surface of the upper flange, three with CFRP tape on the inner surface of the web, three beams with reinforcement located on the inner surface of the bottom flange, and two beams were tested as reference beams without reinforcement. CFRP tape with a width of 50 mm and a thickness of 1.2 mm was used as the reinforcement and was bonded to the beams by SikaDur®-30 adhesive. Precise strain measurement was made using electrofusion strain gauges, and displacement measurement was performed using two Aramis coupled devices in combination with the Tritop machine. Numerical models of the considered beams were developed in the Finite Element Method (FEM) program Abaqus®. Experimental and numerical analysis made it possible to obtain a very high agreement of results. Based on the conducted research, it was proved how important is the impact of the applied reinforcement (CFRP tapes) in thin-walled steel structures, with respect to the classic methods of strengthening steel building structures.

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Energy absorbed ability and damage analysis for honeycomb sandwich material of bio-inspired micro aerial vehicle under low velocity impact

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220975427 ◽

2020 ◽

pp. 095440622097542

Author(s):

Jianxun Du ◽

Peng Hao ◽

Mabao Liu ◽

Rui Xue ◽

Lin’an Li

Keyword(s):

Honeycomb Structure ◽

Low Velocity Impact ◽

Parameter Study ◽

Low Velocity ◽

Micro Aerial Vehicle ◽

Thin Walled Structures ◽

Wide Range ◽

Aerial Vehicle ◽

Thin Walled ◽

The Impact

Because of the advantages of light weight, small size, and good maneuverability, the bio-inspired micro aerial vehicle has a wide range of application prospects and development potential in military and civil areas, and has become one of the research hotspots in the future aviation field. The beetle’s elytra possess high strength and provide the protection of the abdomen while being functional to guarantee its flight performance. In this study, the internal microstructure of beetle’s elytra was observed by scanning electron microscope (SEM), and a variety of bionic thin-walled structures were proposed and modelled. The energy absorption characteristics and protective performance of different configurations of thin-walled structures with hollow columns under impact loading was analyzed by finite element method. The parameter study was carried out to show the influence of the velocity of impactor, the impact angle of the impactor and the wall thickness of honeycomb structure. This study provides an important inspiration for the design of the protective structure of the micro aerial vehicle.

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The Impact of 3D Printing Parameters on the Post-Buckling Behavior of Thin-Walled Structures

Materials ◽

10.3390/ma13214742 ◽

2020 ◽

Vol 13 (21) ◽

pp. 4742

Author(s):

Tomasz Kopecki ◽

Przemysław Mazurek ◽

Łukasz Święch

Keyword(s):

3D Printing ◽

Numerical Solutions ◽

Structure Mapping ◽

Thin Walled Structures ◽

Buckling Behavior ◽

Post Buckling ◽

Thin Walled ◽

The Impact ◽

Printing Direction ◽

Bearing Structure

This study presents the results of experimental research and numerical calculations regarding models of a typical torsion box fragment, which is a common thin-walled load-bearing structure used in aviation technology. A fragment of this structure corresponding to the spar wall was made using 3D printing. The examined system was subjected to twisting and underwent post-critical deformation. The research was aimed at determining the influence of the printing direction of the structure’s individual layers on the system stiffness. The experimental phase was supplemented by nonlinear numerical analyses of the models of the studied systems, taking into account the details of the structure mapping using the laminate concept. The purpose of the calculations was to determine the usefulness of the adopted method for modeling the examined structures by assessing the compliance of numerical solutions with the results of the experiment.

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Experimental Nondestructive Test for Estimation of Buckling Load on Unstiffened Cylindrical Shells Using Vibration Correlation Technique

Shock and Vibration ◽

10.1155/2015/729684 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 8

Author(s):

Kaspars Kalnins ◽

Mariano A. Arbelo ◽

Olgerts Ozolins ◽

Eduards Skukis ◽

Saullo G. P. Castro ◽

...

Keyword(s):

Large Scale ◽

Numerical Models ◽

Cylindrical Shells ◽

Laser Scanner ◽

Experimental Tests ◽

Buckling Load ◽

Correlation Technique ◽

Thin Walled Structures ◽

Instability Point ◽

Thin Walled

Nondestructive methods, to calculate the buckling load of imperfection sensitive thin-walled structures, such as large-scale aerospace structures, are one of the most important techniques for the evaluation of new structures and validation of numerical models. The vibration correlation technique (VCT) allows determining the buckling load for several types of structures without reaching the instability point, but this technique is still under development for thin-walled plates and shells. This paper presents and discusses an experimental verification of a novel approach using vibration correlation technique for the prediction of realistic buckling loads of unstiffened cylindrical shells loaded under axial compression. Four different test structures were manufactured and loaded up to buckling: two composite laminated cylindrical shells and two stainless steel cylinders. In order to characterize a relationship with the applied load, the first natural frequency of vibration and mode shape is measured during testing using a 3D laser scanner. The proposed vibration correlation technique allows one to predict the experimental buckling load with a very good approximation without actually reaching the instability point. Additional experimental tests and numerical models are currently under development to further validate the proposed approach for composite and metallic conical structures.

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Modeling the Varying Dynamics of Thin-Walled Aerospace Structures for Fixture Design Using Genetic Algorithms

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.223.652 ◽

2011 ◽

Vol 223 ◽

pp. 652-661

Author(s):

Mouhab Meshreki ◽

Helmi Attia ◽

József Kövecses

Keyword(s):

Numerical Models ◽

Research Work ◽

Computational Effort ◽

Computational Time ◽

Fixture Design ◽

Structural Elements ◽

Thin Walled Structures ◽

Thin Walled ◽

High Flexibility ◽

High Level

Fixture design for milling of aerospace thin-walled structures is a challenging process due to the high ﬂexibility of the structure and the nonlinear interaction between the forces and the system dynamics. At the same time, the industry is aiming at achieving tight tolerances while maintaining a high level of productivity. Numerical models based on FEM have been developed to simulate the dynamics of thin-walled structures and the effect of the ﬁxture layout. These models require an extensive computational effort, which makes their use for optimization very unpractical. In this research work, a new concept is introduced by using a multi-span plate with torsional and translational springs to simulate the varying dynamics of thin-walled structure during machining. A formulation, based on holonomic constraints, was developed and implemented to take into account the effect of rigid ﬁxture supports. The developed model, which reduces the computational time by one to two orders of magnitude as compared to FE models, is used to predict the dynamic response of complex aerospace structural elements including pockets and ribs while taking into account different ﬁxture layouts. The model predictions are validated numerically. The developed model meets the conﬂicting requirements of prediction accuracy and computational efﬁciency.

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Impact Response of Thin-Walled Tubes: A Prospective Review

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.165.130 ◽

2012 ◽

Vol 165 ◽

pp. 130-134 ◽

Cited By ~ 6

Author(s):

Fauziah Mat ◽

K. Azwan Ismail ◽

S. Yaacob ◽

O. Inayatullah

Keyword(s):

Compressive Loading ◽

Axial Loading ◽

Geometrical Parameters ◽

Axial Deformation ◽

Thin Walled Structures ◽

Structural Applications ◽

Thin Walled ◽

Energy Absorbers ◽

Energy Absorbing ◽

The Impact

Thin-walled structures have been widely used in various structural applications asimpact energy absorbing devices. During an impact situation, thin-walled tubesdemonstrate excellent capability in absorbing greater energy through plastic deformation. In this paper, a review of thin-walled tubes as collapsible energy absorbers is presented.As a mean of improving the impact energy absorption of thin-walled tubes, the influence of geometrical parameters such as length, diameter and wall thickness on the response of thin-walled tubes under compression axial loading are briefly discussed. Several design improvements proposed by previous researchers are also presented. The scope of this review is mainly focus on axial deformation under quasi-static and dynamic compressive loading. Other deformations, such as lateral indentation, inversion and splitting are considered beyond the scope of this paper. This review is intended to assist the future development of thin-walled tubes as efficient energy absorbing elements.

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Investigation of the Impact Analysis of Microscale Thin-Walled Structures Manufactured by High-Speed Machining

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.1599 ◽

2006 ◽

Vol 326-328 ◽

pp. 1599-1602

Author(s):

Bo Sung Shin

Keyword(s):

Finite Element ◽

Cutting Force ◽

High Speed ◽

Impact Analysis ◽

Thin Wall ◽

High Speed Machining ◽

High Speed Cutting ◽

Thin Walled Structures ◽

Thin Walled ◽

The Impact

High-speed machining (HSM) is very useful method as one of the most effective manufacturing processes because it has excellent quality and dimensional accuracy for precision machining. Recently micromachining technologies of various functional materials with very thin walls are needed in the field of electronics, mobile telecommunication and semiconductors. However, HSM is not suitable for microscale thin-walled structures because of the lack of their structure stiffness to resist high-speed cutting force. A microscale thin wall machined by HSM shows the characteristics of the impact behavior because the high-speed cutting force works very shortly on the machined surface. We propose impact analysis model in order to predict the limit thickness of a very thin-wall and investigate its limit thickness of thin-wall manufactured by HSM using finite element method. Also, in order to verify the usefulness of this method, we will compare finite element analyses with experimental results and demonstrate some applications.

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Fem and Experimental Analysis of Thin-Walled Composite Elements Under Compression

International Journal of Applied Mechanics and Engineering ◽

10.1515/ijame-2017-0023 ◽

2017 ◽

Vol 22 (2) ◽

pp. 393-402 ◽

Cited By ~ 8

Author(s):

P. Różyło ◽

P. Wysmulski ◽

K. Falkowicz

Keyword(s):

Numerical Analysis ◽

Cross Section ◽

Numerical Models ◽

Fem Analysis ◽

Geometrical Parameters ◽

Loss Of Stability ◽

Composite Columns ◽

Thin Walled Structures ◽

Operating Stability ◽

Thin Walled

Abstract Thin-walled steel elements in the form of openwork columns with variable geometrical parameters of holes were studied. The samples of thin-walled composite columns were modelled numerically. They were subjected to axial compression to examine their behavior in the critical and post-critical state. The numerical models were articulately supported on the upper and lower edges of the cross-section of the profiles. The numerical analysis was conducted only with respect to the non-linear stability of the structure. The FEM analysis was performed until the material achieved its yield stress. This was done to force the loss of stability by the structures. The numerical analysis was performed using the ABAQUS® software. The numerical analysis was performed only for the elastic range to ensure the operating stability of the tested thin-walled structures.

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Numerical Models of the Connection of Thin-Walled Z-Profile Roof Purlins

Materials ◽

10.3390/ma14216573 ◽

2021 ◽

Vol 14 (21) ◽

pp. 6573

Author(s):

Přemysl Pařenica ◽

Petr Lehner ◽

Jiří Brožovský ◽

Martin Krejsa

Keyword(s):

Cross Section ◽

Numerical Models ◽

Element Model ◽

Cross Sectional ◽

Physical Test ◽

Thin Walled Structures ◽

Practical Design ◽

Thin Walled ◽

Bolt Connection ◽

Experimental Preparation

High thin-walled purlins of Z cross-section are important elements in steel wide-span structures. Their behaviour is influenced by many variables that need to be examined for every specific case. Their practical design thus requires extended knowledge of their behaviour for the possible configurations and dimensions. Numerical analysis verified by experimental investigation can thus enrich such knowledge. Numerical models have the advantage of repeatability and the ability to offer parametric changes. The parametric study presented shows a detailed description of a finite element model of thin-walled cross-sectional roof purlins connected to other roof elements. Models include various approaches to modelling bolt connection. Two schemes of purlins, with and without cleats, are presented. The results of different approaches in numerical modelling are compared with the results of a physical test on a real structure. The article shows a significant agreement in the case of specific approaches and points out the differences with others. The results can be helpful in terms of how to approach the modelling of thin-walled structures and the effective approach to experimental preparation.

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