Strength grading on the basis of high resolution laser scanning and dynamic excitation: a full scale investigation of performance

Olsson, Anders; Oscarsson, Jan

doi:10.1007/s00107-016-1102-6

Cited by 55 publications

(61 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Prior to the test, the modulus of elasticity (E) and the bending strength of the beam were assessed by means of high-resolution laser scanning and dynamic excitation. 26 Information of the tested beam is shown in Table 3.…”

Section: Resultsmentioning

confidence: 99%

Effective cross‐sectional method for timber frame assemblies—definition of coefficients and zero‐strength layers

et al. 2018

View full text Add to dashboard Cite

Summary The load‐bearing capacity of timber members in fire conditions can be evaluated by an analytical design model known as effective cross‐sectional method (ECSM). For this method, an effective cross section of a member in fire is calculated by decreasing the original cross section by a notional charring depth and a so‐called zero‐strength layer. Then, the load‐bearing capacity can be evaluated by applying the mechanical properties as at ambient temperature to this effective cross section. The ECSM for timber frame assemblies (TFA) exposed to standard fire conditions according to European Norm 1363‐1 has been presented earlier in the European technical guideline Fire Safety in Timber Buildings (FSITB) with a limited field of application. This design model considers the fire protection provided by claddings and a limited range of cavity insulations. To cover the fire protection of a wider range of cavity insulation products, a new design approach has been developed. In this study, the zero‐strength layers for TFA with different cavity insulations are determined by means of a series of thermal and mechanical simulations. This paper proposes the protection coefficient for TFA with generic stone wool products as cavity insulation and zero‐strength layers for TFA with different cavity insulations.

show abstract

Section: Resultsmentioning

confidence: 99%

Effective cross‐sectional method for timber frame assemblies—definition of coefficients and zero‐strength layers

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Employing a nearest-neighbour interpolation, the stiffness values are homogenised over each cross section, resulting in a stiffness profile for each board. In Olsson and Oscarsson (2017), it has been shown that the weakest value in such a stiffness profile correlates well to the strength of a single board.…”

Section: Stiffness Profilesmentioning

confidence: 99%

“…In addition, an approach of directly employing the stiffness profiles E(x) was pursued. This approach is inspired by the promising procedure presented in Olsson et al (2013), Oscarsson et al (2014), and Olsson and Oscarsson (2017). Therein, the minimum value of the stiffness profile E(x) of a board is assumed to present the weakest defect.…”

Section: Simplified Models For Prediction Of Glt Stiffness and Strengthmentioning

confidence: 99%

Experimental study on glued laminated timber beams with well-known knot morphology

2018

View full text Add to dashboard Cite

Nowadays, the impact of knots on the failure behaviour of glued laminated timber (GLT) beams is considered by subjecting the single lamellas to a strength grading process, where, i.a., tracheid effect-based laser scanning is used to obtain information about knot properties. This approach single-handedly defines the beam's final strength properties according to current standards. At the same time, advanced production processes of such beams would allow an easy tracking of a scanned board's location, but, at this point, previously obtained detailed information is already disregarded. Therefore, the scanning data is used to virtually reconstruct knot geometries and group them into sections within GLT beams. For this study, a sample of 50 GLT beams of five different configuration types was produced and tested under static four-point-bending until failure. As for each assembled lamella the orientation and position within the corresponding GLT beam is known, several parameters derived from the reconstructed knots can be correlated to effective GLT properties. Furthermore, the crack patterns of the tested beams are manually recorded and used to obtain measures of cracks. A detailed analysis of the generated data and their statistical evaluation show that, in the future, dedicated mechanical models for such timber elements must be developed to realistically predict their strength properties. A potential approach, using fluctuating section-wise effective material properties, is proposed.

show abstract

“…For determining the mechanical properties of individual timber boards, data acquired through laser scanning is used [4]. Based on the obtained data, the 3D knot geometry is reconstructed automatically [5].…”

Section: Materials Model For Timber Boardsmentioning

confidence: 99%

Stochastic engineering framework for timber structural elements

Kandler

Lukacevic

Wolff

et al. 2018

Beton und Stahlbetonbau

View full text Add to dashboard Cite

Due to the natural growth process of trees, the resulting wooden boards show a high amount of random fluctuation in their mechanical properties. In this work, a framework able to consider the impact of random stiffness fluctuations of wooden boards on the performance of glued laminated timber (GLT) is presented. A 2D finite element model is employed to depict the interactions between individual laminations and is integrated into a commercial robustness analysis and optimisation software package. The mechanical properties of each board are obtained during the grading process and are condensed into so‐called stiffness and strength profiles. Based thereon, a probabilistic material model is developed for the random generation of an arbitrary number of stiffness and strength profiles. On basis of the probabilistic material model and the mechanical FE model, the sensitivity to changes in the design can be explored. Subsequently, the optimal design parameters of the user‐defined structure are identified. An exemplary application scenario shows the workflow for determining the optimum hole dimensions and location in a GLT beam. The material model indicates large scatter in the mechanical properties, leading to conservative results. Nonetheless, the example shows the strengths of the employed workflow from sensitivity analysis to best designs.

show abstract

Strength grading on the basis of high resolution laser scanning and dynamic excitation: a full scale investigation of performance

Cited by 55 publications

References 6 publications

Effective cross‐sectional method for timber frame assemblies—definition of coefficients and zero‐strength layers

Effective cross‐sectional method for timber frame assemblies—definition of coefficients and zero‐strength layers

Experimental study on glued laminated timber beams with well-known knot morphology

Stochastic engineering framework for timber structural elements

Contact Info

Product

Resources

About