Failure behavior of electromagnetic driven nailing riveted joint for Al/steel structures subjected to fatigue loading

2021 ◽  
pp. 105941
Author(s):  
Hao Jiang ◽  
Bingkun Li ◽  
Guangyao Li ◽  
Junjia Cui
Keyword(s):  
Steel Structures ◽  
Fatigue Loading ◽  
Failure Behavior ◽  
Riveted Joint

Causes of Structural Failures with Steel Structures

2017 ◽  
Author(s):  
Goran Alpsten
Keyword(s):  
Structural Damage ◽  
Human Error ◽  
Structural Reliability ◽  
Steel Structures ◽  
Fatigue Loading ◽  
Structural Instability ◽  
Human Errors ◽  
Collapse Mode ◽  
Load Carrying ◽  
Structural Failures

This paper is based on the experience from investigating over 400 structural collapses, incidents and serious structural damage cases with steel structures which have occurred over the past four centuries. The cause of the failures is most often a gross human error rather than a combination of “normal” variations in parameters affecting the load-carrying capacity, as considered in normal design procedures and structural reliability analyses. Human errors in execution are more prevalent as cause for the failures than errors in the design process, and the construction phase appears particularly prone to human errors. For normal steel structures with quasi-static (non-fatigue) loading, various structural instability phenomena have been observed to be the main collapse mode. An important observation is that welds are not as critical a cause of structural steel failures for statically loaded steel structures as implicitly understood in current regulations and rules for design and execution criteria.

scholarly journals Failure assessment of steel/CFRP double strap joints

2017 ◽  
Author(s):  
Hamid Reza Majidi ◽  
Seyed Mohammad Javad Razavi ◽  
Filippo Berto
Keyword(s):  
Failure Load ◽  
Steel Structures ◽  
Predictive Modelling ◽  
Failure Behavior ◽  
Static Tensile Loading ◽  
Failure Assessment ◽  
Theoretical Predictions ◽  
Static Tensile ◽  
Failure Loads ◽  
Good Agreement

In the current study, the failure behavior of retrofitted steel structures was studied experimentally and theoretically with steel/CFRP double strap joints (DSJs) under quasi-static tensile loading. A series of DSJs with different bonding lengths are also considered and examined to experimentally assess the effective bond length. To predict the failure load values of the tested specimens, a new stress-based criterion, namely the point stress (PS) criterion is proposed. Although some theoretical predictive modelling for the strength between steel/CFRP joints under various loading conditions has been presented, in this work by using the new proposed approach, one can calculate rapidly and conveniently the failure loads of the steel/CFRP specimens. Furthermore, to assess the validity of the new proposed criterion, further experimental data on steel/CFRP DSJs available in the open literature are predicted using the PS criterion. Finally, it was found that a good agreement exists between the experimental results and the theoretical predictions based on the PS criterion.

Investigation of the fatigue behavior of thermoplastic composites by load increase tests

2020 ◽  
pp. 002199832095452
Author(s):  
Andreas Baumann ◽  
Sebastian Backe ◽  
Joachim Hausmann
Keyword(s):  
Fatigue Behavior ◽  
Numerical Data ◽  
Fatigue Loading ◽  
Polyamide 6 ◽  
Heat Emission ◽  
Thermoplastic Composites ◽  
Failure Behavior ◽  
Glass Fiber Reinforced ◽  
The Matrix ◽  
Load Increase

Fatigue is one major load case in many structures for transport applications. New materials often lack the necessary data base for a fast application in cyclic loaded components due to time consuming testing series. The aim of this study is the evaluation of the load increase test as method to determine a possible fatigue limit of glass fiber reinforced polyamide 6. Under the working hypothesis that cracks are the main contributors for heat emission, the results show that the investigated material exhibits a different behavior in comparison to thermosets. Instead of crack formation experimental and numerical data indicate that the matrix relaxes under fatigue loading. This relaxation could potentially lead to crack prevention but might also result in the observed sudden failure behavior of the material. These findings suggest a totally different behavior of thermoplastic composites under fatigue loading.

Damage Assessment of Similar Martensitic Welds Under Creep, Fatigue and Creep-Fatigue Loading

2020 ◽  
Author(s):  
Thorben Bender ◽  
Andreas Klenk ◽  
Stefan Weihe
Keyword(s):  
Base Metal ◽  
Fatigue Behavior ◽  
Base Material ◽  
Fatigue Loading ◽  
Design Guidelines ◽  
Failure Behavior ◽  
Martensitic Steels ◽  
Viscoplastic Material ◽  
Local Strains ◽  
Creep Fatigue

Abstract For the assessment of welds under high-temperature conditions in the creep or creep-fatigue regimes, the knowledge on the damage location and its temporal evolution are of high importance. The failure behavior of similar welds of ferritic-martensitic steels in the creep regime is well known. For creep-fatigue loading, the behavior of welds is still subject to research but it seems that the heat affected zone (HAZ) limits the lifetime of welded components as well. This local failure behavior is not reflected in design guidelines using weld reduction factors or in typical assessment approaches. The evaluation of local strains and stresses in the HAZ is unavoidable. For the improvement of design and inspection guidelines, a more detailed consideration of weld behavior is of interest. In this paper, an overview of current developments in the assessment of welds under creep, fatigue, and creep-fatigue loading conditions is given. An assessment approach for creep damage and failure, including the prediction of rupture time and location, is presented. The assessment is based on numerical analyses considering the different behavior of base material and HAZ represented by three different subzones. The approach is validated with the simulation of a uniaxial cross weld, creep crack, and component tests. Whereas the creep behavior of the HAZ compared to base metal is quite well known, there is only little knowledge of their fatigue behavior. Using a set of fatigue tests on HAZ, base metal specimens and cross weld specimens, the influence of fatigue and creep-fatigue loading on the lifetime and failure location of a weld will be discussed. For the numerical simulations, a viscoplastic material law of Chaboche type is used and an evaluation of the local strains in the HAZ allows an attempt to explain the observed failure locations.

Fatigue strength of a groove weld on steel backing

1984 ◽  
Vol 11 (4) ◽  
pp. 692-700 ◽  
Author(s):  
K. A. Baker ◽  
G. L. Kulak
Keyword(s):  
Finite Element Analysis ◽  
Fatigue Strength ◽  
Fatigue Cracks ◽  
Steel Structures ◽  
Fatigue Loading ◽  
Test Results ◽  
Fabrication Technique ◽  
Element Analysis ◽  
Fillet Weld ◽  
Local Stresses

Groove welding made from one side is a common fabrication technique for joints in steel structures. If a steel backing bar is used, current (1983) North American specifications require that it be removed after welding and the weld ground flush if the detail is to be located transversely to the direction of stress and fatigue loaded. This is an expensive, and in some cases impractical, procedure. In the investigation reported herein, data concerning the fatigue strength of a groove weld with steel backing bar detail have been obtained experimentally. The backing bar was attached with intermittent fillet welds. A finite element analysis has been used to assist in interpretation of the test results.The analysis showed that high local stresses are present at the toe of the fillet weld. However, high stresses also exist at the flush-ground face of the groove weld, and the test results indicated that all fatigue cracks started at this side of the detail. When this detail is present in a structure and subjected to a fatigue loading, category C of the AASHTO or CSA specifications will provide a suitable basis for design. Key words: failure, fatigue, steel, welding.

scholarly journals Identification of Nonlinear Dynamic Behavior and Failure for Riveted Joint Assemblies

2000 ◽  
Vol 7 (3) ◽  
pp. 121-138 ◽  
Author(s):  
B. Langrand ◽  
E. Markiewicz ◽  
E. Deletombe ◽  
P. Drazétic
Keyword(s):  
Sheet Metal ◽  
Constitutive Models ◽  
Numerical Procedure ◽  
Rate Sensitivity ◽  
Type Specimen ◽  
Metal Plate ◽  
Failure Behavior ◽  
Dynamic Experiments ◽  
Riveted Joint

Many different types of rivets need to be modeled to analyze the crashworthiness of aircraft structures. A numerical procedure based on FE modeling and characterization of material failure constitutive models is proposed herein with the aim of limiting the costs of experimental procedures otherwise necessary to obtain these data. Quasi-static and dynamic experiments were carried out on elementary tension (punched) and shear (riveted) specimens. No strain rate sensitivity was detected in the failure behavior of the riveted joint assemblies. Experimental data were used to identify the Gurson damage parameters of each material (2024-T351 and 7050 aluminum alloys for the sheet metal plate and the rivet respectively) by an inverse method. Characterization gave rise to satisfactory correlation between FE models and experiments. Optimized parameters were validated for each material by means of a uniaxial tension test for the sheet metal plate and an ARCAN type specimen in pure tension for the rivet.

scholarly journals Bonded CFRP/Steel Systems, Remedies of Bond Degradation and Behaviour of CFRP Repaired Steel: An Overview

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1533
Author(s):  
Daniel Borrie ◽  
Saad Al-Saadi ◽  
Xiao-Ling Zhao ◽  
R. K. Singh Singh Raman ◽  
Yu Bai
Keyword(s):  
Influencing Factor ◽  
Surface Preparation ◽  
Steel Structures ◽  
Fatigue Loading ◽  
Civil Structures ◽  
Industrial Practice ◽  
Multiple Parameters ◽  
Frp Composite ◽  
Bond Degradation ◽  
Welding Steel

This literature review has examined the use of FRP composite materials as a potential retrofitting technique for civil structures. Importantly, the various material properties, bond mechanisms, durability issues and fatigue resistance have been discussed. Studies exploring the performance of CFRP repaired steel have strongly indicated its potential as a rehabilitation material. These systems offer many improvements over the current bulky and less chemically resistant methods of bolting or welding steel plate patches. This review has established and highlighted the factors that affect CFRP/steel bond durability, namely surface preparation, curing, corrosion, fatigue loading, temperature and moisture ingress through studies that focus on their effect. These studies, however, often focus on a single influencing factor or design criteria. Only limited studies have investigated multiple parameters applied simultaneously, even though they commonly occur together in industrial practice. This review aimed to summarise the numerous influencing parameters to give a clearer understanding of the relevance of CFRP repaired steel structures.

Elastic Properties and Failure Behavior of Tiled Laminate Composites

2018 ◽  
Vol 774 ◽  
pp. 564-569 ◽  
Author(s):  
Wouter de Corte ◽  
Arne Jansseune ◽  
Wim van Paepegem ◽  
Jan Peeters
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Properties ◽  
Fatigue Loading ◽  
Failure Behavior ◽  
Element Analysis ◽  
Laminate Composites ◽  
Permanent Formwork ◽  
Laminate Theory ◽  
Highly Loaded

This paper focuses on the elastic properties and the failure behavior of tiled laminate composites. Such laminates, in which the plies are not parallel to the outer surfaces are found in InfraCore® based GFRP panels. This technology is developed for the construction of a robust FRP panel that is applicable for highly loaded structures, e.g. for bridges or lock gates. In general, the drawback in traditional FRP sandwich structures has always been debonding of skin and core. Such a debonding problem may occur after impact, followed by fatigue loading. Through the use of the InfraCore® technology, debonding is no longer possible, as multiple overlapping Z-shaped and two-flanged web structures are alternated with polyurethane foam cores acting as non-structural permanent formwork. Consequently, the fibers in the upper and lower skins as well as in the vertical webs run in all directions, especially in the connection between them, rendering a resin-dominated crack propagation impossible. As a result of the integration of core and skin reinforcement, a skin material is created in which the reinforcement is not parallel to the outer surfaces, but at a small angle. Such stacking is called a tiled laminate (TL), as opposed to plane-parallel (PP) and is not fully described by the classic laminate theory. In the paper, finite element analysis is used to assess the effect of the ply angle and the interlaminar properties on the assessment of stiffness and failure behavior of a tiled laminate.

scholarly journals On Welding Residual Stresses Near Fatigue Crack Tips

2014 ◽  
Vol 996 ◽  
pp. 801-807 ◽  
Author(s):  
Jonas Hensel ◽  
Thomas Nitschke-Pagel ◽  
Klaus Dilger
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Fatigue Strength ◽  
Yield Strength ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Steel Structures ◽  
Fatigue Loading ◽  
Diffraction Measurement ◽  
Stress Effect

Residual stresses in welded joints are supposed to change during fatigue loading. Residual stresses can be, depending on the loading conditions, relaxed as well as build up and they can be affected by fatigue crack growth. Furthermore residual stresses are supposed to affect the fatigue strength of welded steel structures. However, tensile residual stresses decrease and compressive residual stresses increase the fatigue strength. This residual stress effect on the fatigue strength is mostly explained with different crack propagation rates.The presented work is on welded longitudinal stiffeners, made of unalloyed fine grained carbon steel, with different fatigue crack lengths in which residual stresses have been determined. The residual stress measurement was conducted using Neutron diffraction. The results of the diffraction measurement show that the initial tensile residual stresses near the weld toe are, caused by phase transformation at low temperatures, below the base materials yield strength. Tensile residual stresses in the order of the yield strength can be found below the materials surface. These areas of high residual stresses are moving with the propagating crack tip through the specimen during fatigue loading.

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