Sains Malaysiana 47(4)(2018): 683-689

http://dx.doi.org/10.17576/jsm-2018-4702-05

Evaluation of Tensile Strength of Brazilian Test under Solid and Ring Disks using Finite Element Analysis

(Penilaian Kekuatan Regangan bagi Uji Kaji Brazil di bawah Cakera Utuh dan Cincin menggunakan Analisis Unsur Terhingga)

RINI ASNIDA ABDULLAH¹* & TAKASHI TSUTSUMI²

¹Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor Darul Takzim, Malaysia

²Urban Environmental Design and Engineering, National Institute of Technology, Kagoshima College, Hayato, Kirishima, Kagoshima 899-5193, Japan

Diserahkan: 20 Jun 2017/Diterima: 26 Oktober 2017

ABSTRACT

The tensile strength of intact rock materials has been determined by indirect method more frequent than the direct method. The most commonly used indirect method is Brazilian test. Stress and deformability undergo during the test reflected by geometry shape of the samples with respect to the different diameter ratio. This study focuses on influence of geometry shape in solid and ring disk with different diameter ratio on the stress distribution and deformations within sandstone subjected to indirect tensile loading by Brazilian test. Then, the finite element method in RS² software was utilised to simulate and gain in depth understanding the behaviour of Brazilian test. The analysis shown that the maximum tensile strength in a ring disk with diameter ratio of 0.1 is three times higher than in solid disk. Meanwhile, as the diameter ratio of ring disk increases, it produces lower tensile strength. The numerical simulation also has successfully illustrated the shear failure which observed near the loading platen of solid disk during Brazilian test. The finite element analysis utilised in this research has successfully enables the stress distribution and deformation behaviour of the rock under tension to be studied closely.

Keywords: Brazilian test; finite element method; ring test; RS²; tensile strength

ABSTRAK

Kekuatan regangan batuan utuh ditentukan dengan kaedah tidak langsung lebih kerap berbanding daripada kaedah langsung. Kaedah tidak langsung yang paling biasa digunakan adalah uji kaji Brazil. Tekanan dan perubahan bentuk yang dialami semasa uji kaji merujuk kepada bentuk geometri sampel dengan perkaitan nisbah diameter yang berbeza. Kajian ini memberi tumpuan kepada pengaruh bentuk geometri dalam cakera utuh dan cincin dengan nisbah diameter yang berbeza pada agihan tegasan dan perubahan bentuk di dalam batu pasir yang tertakluk kepada bebanan regangan tidak langsung dari uji kaji Brazil. Kaedah unsur terhingga di dalam perisian RS² telah digunakan untuk mensimulasi dan memahami dengan lebih mendalam sifat uji kaji Brazil. Analisis menunjukkan bahawa kekuatan regangan maksima di dalam cakera cincin dengan nisbah diameter 0.1 adalah tiga kali lebih besar daripada cakera utuh. Sementara itu, semakin besar nisbah diameter cakera cincin, semakin kecil kekuatan regangan yang dihasilkan. Simulasi berangka telah berjaya menggambarkan tegasan ricih yang wujud berhampiran beban plat di dalam uji kaji Brazil pada cakera utuh. Analisis unsur terhingga yang digunakan dalam kajian ini telah berjaya membolehkan agihan tegasan dan perubahan sifat bentuk batuan di bawah tekanan untuk dikaji dengan teliti.

Kata kunci: Kaedah unsur terhingga; kekuatan regangan; RS²; uji kaji Brazil; uji kaji cincin

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*Pengarang untuk surat-menyurat; email: asnida@utm.my