Residual stress measurements on cold-formed HSS hollow section columns

Somodi, B.; Kövesdi, Balázs

doi:10.1016/j.jcsr.2016.10.008

Cited by 63 publications

(42 citation statements)

References 9 publications

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“…Solving those three matrix systems, the unknown vectors P j , Q j and T j are found; finally, using equation (5), the stress distribution can be obtained for each depth j in the coordinate system defined by the gauges. The non-dimensional coefficients a ij and b ij represent the strain relieved after the removal of step i due to a unit stress at depth j.…”

Section: Residual Stress Measurement By the Holedrilling Methodsmentioning

confidence: 99%

“…3 Experimental determination of residual stresses in those cold-formed profiles usually relies on X-ray diffraction 4 or in sectioning methods. 5,6 However, while the former is expensive, the latter gives coarse and nonlocalised measurements. As an alternative, hole-drilling method is an experimental technique that can be used to obtain residual stresses in a workpiece point by drilling a small hole on a material surface.…”

Section: Introductionmentioning

confidence: 99%

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Application of the hole-drilling method for the evaluation of residual stresses near rounded ends

Alegre

Díaz

Cuesta

et al. 2019

The Journal of Strain Analysis for Engineering Design

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The experimental measurement of residual stresses by the hole-drilling method is a versatile technique due to its great simplicity. The technique consists of drilling on a material surface and measuring the relieved deformation on the surface by means of strain gauge rosettes. The most widespread method to obtain residual stresses from relieved deformation is the integral method and is found in the ASTM E837-13a standard. The procedure is standardised for very specific conditions, which are based on the application of the technique on a large flat-plate. To apply this technique to situations outside the standard scope, it is necessary to perform studies that validate its applicability. One of these situations is to evaluate the stresses introduced in hot- or cold-rolled profiles, where the residual stresses are concentrated on the rounded corners generated by rolling operations. In this study, a numerical simulation by finite elements has been carried out to obtain the relieved deformations for the case of drilling near rounded ends. The results show that the hole-drilling technique is applicable for the case of rounded ends; however, there is a significant deviation from the flat-plate condition which can be minimised by considering new matrices for the specific rounding radius and thickness of the analysed workpiece.

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Section: Residual Stress Measurement By the Holedrilling Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of the hole-drilling method for the evaluation of residual stresses near rounded ends

Alegre

Díaz

Cuesta

et al. 2019

The Journal of Strain Analysis for Engineering Design

View full text Add to dashboard Cite

show abstract

“…Some researchers consider that cold forming introduces mostly transversal residual stresses and that longitudinal residual stresses are almost inexistent. The model of residual stresses chosen is presented and has been applied for NSS and HSS as recommended in Somodi and Kövesdi (2017a, b). Compressive residual stresses were introduced in the flat part and tensile stresses in the corner.…”

Section: Methodsmentioning

confidence: 99%

Stability analysis of newly developed polygonal cross-sections for lattice wind towers

2018

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The pursuit for cheaper energy is leading the current wind tower design to increased heights. Common wind turbine tower designs would generate unjustified costs for transportation and erection leading to inefficient use of materials. In order to reduce these costs, several simplified erection methods have been proposed. One of such is the hybrid lattice-tubular steel tower. For economic feasibility, built-up cold-formed polygonal cross-sections have been proposed for the lattice part. This article presents a numerical investigation of the failure modes of closed polygonal cross-sections. The first part contains a presentation of structural systems which incorporate elements composed of plates and cold-formed members. The evaluation of the polygonal sections is done by means of finite element analysis considering local and global geometrical imperfections and residual stresses generated in the fabrication procedure. A comparative study is performed between several finite element models to propose a corresponding European buckling curve for calculating the flexural buckling resistance. The results show that the design of polygonal sections can be done according to European buckling curves methodology.

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“…Previous research results show that high strength steel columns have favourable flexural buckling behaviour than similar columns from normal strength steel, and the application of the current design rules gives uneconomic results [2], [3]. The main reason is that the typical residual stress in high strength steel sections is different than in case of normal strength steel sections [4], [5]. The current design rule for flexural buckling resistance in the EN 1993-1-1 [1] is based on the Ayrton-Perry formula taking the effect of the residual stress and geometric imperfections as generalized imperfections into account.…”

Section: Introductionmentioning

confidence: 98%

05.20: Modified Ayrton‐Perry formula for flexural buckling of HSS welded box sections

Kövesdi

Somodi

2017

ce papers

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The residual stress in steel structural elements has significant influence on the flexural buckling behaviour of compressed members. This phenomenon causes that hot-rolled, cold-formed and welded sections with the same geometry have different flexural buckling behaviour and resistance. Previous research results showed that the residual stress pattern of members made from high strength steel (HSS) is different than for normal strength steel (NSS) structures, which results in different flexural buckling behaviour. The current design rules of the EN 1993-1-1 [1] for column buckling resistance is based on the Ayrton-Perry type formula taking the effect of the residual stress and geometric imperfections as generalized imperfections into account. The effect of the residual stress magnitudes is not implemented directly in the method, therefore its implementation could result a more precise column buckling curve, which can differentiate between hot-rolled, coldformed and welded sections, as well as NSS and HSS structures. The current paper introduces a method, which implements the effect of the residual stress pattern of welded box section columns into the Ayrton-Perry type formula. This new formulation results in a revised and improved column buckling curve. This new buckling curve is compared to the general buckling curves of the EN 1993-1-1 [1] and also compared to recent experimental and numerical results conducted by the authors. The parameters of the improved buckling curve are studied and evaluated in the details. The effect of the magnitude of the residual stress on the buckling resistance is studied and compared to the numerical results. Based on a detailed experimental and numerical research program an improved formulation of the Ayrton-Perry formula is proposed, which is validated for welded square box sections applicable for NSS and also for HSS grades.

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Residual stress measurements on cold-formed HSS hollow section columns

Cited by 63 publications

References 9 publications

Application of the hole-drilling method for the evaluation of residual stresses near rounded ends

Application of the hole-drilling method for the evaluation of residual stresses near rounded ends

Stability analysis of newly developed polygonal cross-sections for lattice wind towers

05.20: Modified Ayrton‐Perry formula for flexural buckling of HSS welded box sections

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