Numerical analysis on stress and displacement of tapered cantilever castellated steel beam with circular openingsTaufiq Ilham Maulana, Hakas Prayuda, Bagus Soebandono, Martyana Dwi Cahyati and Eva Hanifatu ZahraMATEC Web Conf., 195 (2018) 02007DOI: https://doi.org/10.1051/matecconf/201819502007