Development of methods to infer structural design properties from non-destructive testing, as a basis for bamboo grading

    Student thesis: Doctoral ThesisDoctor of Philosophy

    Abstract

    This critical overview contains six publications. The first two publications (Trujillo, Ramage et al. 2013; Trujillo, 2013) identify that at their time of publication, grading of bamboo culms (or stems) was a poorly researched and understood topic. Extant guidance was cursory and rarely underpinned by research. Machine grading was non-existent. By identifying which properties and characteristics of bamboo culms affect their structural performance, the third publication (Trujillo and López, 2016) creates the basis for a grading methodology. This third publication also critiques some of the experimental procedures used to determine these properties and stresses the need to consider geometric characteristics of a species, as well as its physical and mechanical properties.

    The fourth publication within the portfolio (Trujillo et al. 2017) presents the findings following the extensive flexural testing of Guadua angustifolia Kunth culms. Numerous non-destructively measured characteristics and properties were measured including linear mass (qtest) and flexural stiffness (EIm,s). External diameter (D) and wall-thickness (t) were also recorded for each specimen. Moment at failure (or flexural capacity - Mult) was also recorded. Correlations between the non-destructively measured properties and destructively-determined properties were undertaken. The publication identifies that correlations between extensive properties (EIm,s versus Mult and qtest versus Mult) are very strong (R2 > 0.86), thus rendering them potentially very good predictors for bamboo machine grading.

    The fifth publication, ISO 19624:2018, is an international standard that presents the framework to develop a visual or machine grading methodology by specifying the considerations or requirements in terms of sampling, testing and frequency of testing to develop a grading methodology. An example of a hybrid ‘capacity grading’ procedure is presented in Annex A.

    Trujillo, Ramage et al. (2013) also identifies that bamboo connection design is an inadequately researched field. The sixth publication (Trujillo and Malkowska, 2018) addresses this inadequacy by experimentally determining three ‘connection design properties’ (dowel embedment strength, slip modulus and screw withdrawal capacity) for Guadua angustifolia Kunth.

    Date of AwardNov 2020
    Original languageEnglish
    Awarding Institution
    • Coventry University
    SupervisorJohn Karadelis (Supervisor)

    Keywords

    • bamboo
    • standards
    • grading
    • connection design
    • non-destructive testing

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