Performance study on mounting system for displacement transducer in mechanical tests of timber samples using photogrammetry method

Abstract

Performance study on mounting system for displacement transducer in mechanical tests of timber samples using photogrammetry method, Wood Material Science & Engineering,

A new concept of bio-based prestress technology with experimental Proof-of-Concept on Bamboo-Timber composite beams

“…Glulam beam is one of the best options to trial this new concept. The glulam [20][21][22][23][24] is commonly used in modern timber construction with excellent structural performance as well as thermal insulation, attractive textures, and very economic, sustainable materials. Manufacturing multi-material/species glulam beams with components that have different strength grades is an effective way to produce low cost, high strength structural members with optimised material exploitation.…”

Applicability of the torsion test and photogrammetric approach on structural timber beams

“…Torsion tests are of benefit as they are the only method that imposes a state of pure shear stress on a specimen, and have proven to have more advantages for measuring the shear modulus value of timber and glulam beams (Vafai and Pincus, 1973; Hindman et al, 2005). Recently, the torsion test has been adopted more frequently by researchers (Vafai and Pincus, 1973; Gharavi and Zhang, 2018; Gharavi and Zhang, 2018; Gharavi et al, 2018; Gupta et al, 2002; Gupta and Siller, 2005; Khokar, 2010; Mohamed et al, 2021a, 2021b; Mohamed et al, 2015; Zhang, 2011; Zhang, 2012) to evaluate the shear modulus of structural-size timber and glulam beams, as well as laminated structural glass beams (Uheida et al, 2021).…”

“…When performing torsion tests, one must consider how to effectively measure and extract the torque-rotation relationship – unfortunately, it is not feasible to use the torsion machines end rotation data alone to determine the beams mechanical properties such as the shear modulus (Gharavi et al, 2018; Mohamed et al, 2021a, 2021b; Zhang et al, 2012). Measuring the required torsional displacements can be performed with fair accuracy using traditional contact-based devices such as inclinometers or linear variable differential transformers (LVDTs) (Mohamed et al, 2021a, 2021b, 2021c; Mohamed et al, 2015; Zhang, 2012), although these still come with limitations. Inclinometers are limited to one device per data point, the measurement accuracy is limited by the base size of the sensor and can only measure in x and y dimensions.…”

“…Monitoring tools using photogrammetry and image processing have been used in timber to measure mechanical properties, 3D displacements, or deformations at various points of the same specimen, as proposed in various experiments (Gharavi et al, 2017; Gharavi and Zhang, 2018; Gharavi et al, 2018; Mohamed et al, 2021a, 2021b, 2021c; Mohamed et al, 2015; Zhang, 2011; Zhang, 2012; Zhang et al, 2012; Choi et al, 1991; Dahl and Malo 2009a, 2009b; Franke et al, 2007; Franke et al, 2007; Garcia and Orteu, 2001; Maas and Hampel, 2006). In contrast to traditional techniques, the binocular stereo vision approach is a non-contact measurement technique that can be used to extract reliable measurements of physical objects from stereo images.…”

Verification of the photogrammetric approach on the torsion test method for timber beams

“…This test is the only method that imposes a state of pure shear stress on a specimen, and it has been proven to have more advantages for measuring the shear modulus value of timber and glulam beams. Recently, the torsion test has been adopted more frequently by researchers to evaluate the shear modulus of structural-size timber and glulam beams (Gupta et al 2002; Gupta and Siller 2005; Hindman et al 2005; Khokhar et al 2010; Zhang et al 2011; Mohamed et al 2015; Mohamed, A., et al 2021; Mohamed, A., et al 2021; Gharavi et al 2017; Gharavi et al 2018; Gharavi, N. and H. Zhang, 2018), as well as laminated structural glass beams (Uheida, K., et al 2021; Zhang et al 2021).…”