Kajian Analitik Pengaruh Beban Termal Terhadap Stabilitas Tiang Pipa Baja
DOI:
https://doi.org/10.5614/jts.2007.14.3.4Keywords:
Stabilitas, Beban termal, Tegangan sisa, Ketidaklurusan tiang, Suhu leleh pertama, Suhu runtuh, Beban antitekuk.Abstract
Abstrak. Kolom pipa baja banyak dijumpai pada bangunan industri, khususnya pada bangunan instalasi kilang minyak. Banyak diantara kolom pipa baja direncanakan untuk beroperasi pada kondisi temperatur tinggi. Perencanaan beban termal hingga 800oC dari struktur pipa baja di lingkungan kilang minyak merupakan perencanaan yang tidak lazim dan ini memerlukan kajian khusus. Makalah ini menyampaikan kajian kondisi khusus dari tiang pipa baja yang ditumpu sederhana dan beroperasi pada beban termal tinggi yang terdistribusi sepanjang pipa hingga 800oC. Perencanaan di bawah aksi temperatur tinggi menjadikan pemecahan persoalan semakin sulit untuk mengikuti kriteria perencanaan yang tersedia. Kondisi ketidaksempurnaan awal kolom, seperti tegangan sisa, dan ketidaklurusan kolom juga merupakan besaran yang turut diperhitungkan di dalam simulasi ini.Stabilitas tiang pipa baja akan menjadi pertimbangan penting di dalam perencanaannya. Metoda numerik berbasis elemen hingga dipergunakan untuk mensimulasikan masalah yang diajukan ini. Hasil analisis menunjukkan bahwa stabilitas tiang pipa baja yang diindikasikan dengan suhu leleh pertama dan suhu runtuh tiang sangat dipengaruhi terutama oleh dimensi dari tiang, ketidaklurusan tiang, tegangan residu, serta distribusi beban termal. Beban antitekuk minimum meningkat nilainya seiring dengan meningkatnya beban termal, namun beban antitekuk maksimum menurun nilainya dengan meningkatnya beban termal.Abstract. Steel pipes are found at almost industrial structures, especially in refinery plant. More and more often, steel pipes have to be designed to operate at higher temperature. Design temperature until 8000C which we find at refinery plant is not uncommon. This paper deals with particular case of pillar of steel pipe which is simply supported and operates at elevated and distributed temperature until 8000C. When the design of temperature is very high, it becomes increasingly difficult to meet the current design criterion. Initial imperfection like residual stress and out-of-straightness is covered in this simulation. In this simulation, initial imperfect column condition such as residual stress, out-of-straightness are considerated as well. Stability becomes to be an important consideration. Numerical method based on finite element is used to simulate this case. The result of the analysis shows that the stability of steel pipe indicated by first yield temperature and collapse temperature are determined especially by dimension of steel pipe, out-of-straightness, residual stress, as well as thermal load distribution. The minimum antibuckle axial force increases with the thermal load, but the opposite condition for the maximum antibuckle axial force.
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