Quadruple LVDT local rotational displacement measurement in torsional shear tests

Local measurements of the polar deformation response in a hollow cylinder apparatus

“…Although theoretically sound, the local instrumentation set up of inclinometers and proximity transducers used by Hight et al (1983) in the large IC HCA is difficult to implement unless the outer specimen radius is at least 100 mm (Huang et al 2007). This paper describes the set up, calibration and performance of the customised inclinometers and proximity transducers that measure the local deformation response of a smaller testspecimen (35.5 mm inner radius; 50.0 mm outer radius and 200 mm in overall length, H) commonly used in several HCA currently available in a few research laboratories in the world, including University College Dublin (UCD).…”

“…Measurement errors due to apparatus compliance and specimen end-restraint and bedding effects are excluded when the deformation response is measured within the mid-third of the specimen length, with a typical aspect (height to diameter) ratio of two (Jardine et al 1984;Baldi et al 1988). Many innovative techniques have been developed to measure the deformations locally including displacement transducers LVDTs (Cuccovillo and Coop 1997;Huang et al 2007); electrolevel inclinometers (Jardine et al 1984;Symes and Burland 1984); Hall-effect transducers (Clayton and Khatrush 1986); image analysis (Rechenmacher and Finno, 2004) as well as non-contacting electromagnetic techniques, e.g. proximity transducers (Brown et al 1980;Symes and Burland 1984;Hird and Yung 1989;Lo Presti et al 1993;Menkiti 1995).…”