Utomo, Fachrur Rozi (2008) Analisa sifat perambatan retak pada pipa mildsteel dengan metode elemen hingga. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Pada konstruksi kapal, selain profil dan pelat, juga digunakan pipa baja sebagai komponen konstruksi. Sebagai akibatnya, sifat-sifat mekanis, termasuk perambatan retak pada komponen konstruksi, menjadi penting untuk diketahui. Studi dilakukan pada pipa _mild steel_ untuk cacat _outer circumferential crack_ dengan pembebanan _tension_ atau mode pembebanan menggunakan Mode I. Penggunaan metode elemen hingga dengan program aplikasi ANSYS 10.0 ini akan menghasilkan nilai _Stress Intensity Factor_. Selanjutnya, dengan persamaan Paris akan diperoleh kecepatan perambatan retak tersebut.
Pada analisis ini digunakan material pipa _mild steel_ X-65 dengan variasi dimensi panjang retak (c/nR) dan tebal pipa. Dari hasil analisis didapatkan bahwa semakin dalam retak, maka semakin besar nilai ΔK dan semakin tebal pipa, maka semakin lambat pertumbuhan retaknya. Hal ini dapat dilihat pada pipa dengan tebal 20 mm untuk c/nR = 0,04, pada setiap pertumbuhan retak 1% diperoleh rata-rata persentase pertambahan ΔK sebesar 14,32%. Untuk pipa dengan tebal 40 mm dengan c/nR = 0,04, pada setiap pertumbuhan retak 1% diperoleh rata-rata persentase pertambahan ΔK sebesar 8,68%. Selain itu, panjang retak pada pipa (c/nR) berpengaruh terhadap besarnya _Stress Intensity Factor_. Semakin panjang retak, maka semakin cepat pertumbuhan retaknya. Pada pipa dengan tebal 20 mm dan c/nR = 0,04, persentase pertambahan ΔK sebesar 14,32%. Untuk c/nR = 0,1, persentase pertambahan ΔK sebesar 21,82%. Untuk c/nR = 0,3, persentase pertambahan ΔK sebesar 34,47%. Untuk c/nR = 0,4, persentase pertambahan ΔK sebesar 34,82%. Hal ini sesuai dengan teori kegagalan pertumbuhan retak material, yaitu retak pada suatu material akan terus merambat sampai mencapai kondisi patah (_failure_).
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In ship construction, besides profiles and plates, steel pipes are also used as structural components. Consequently, their mechanical characteristics, including crack growth behavior, are important to understand. This study was conducted on a mild steel pipe with an outer circumferential crack under tensile loading or Mode I loading. The Finite Element Method using ANSYS 10.0 was applied to obtain the Stress Intensity Factor. Furthermore, the Paris equation was used to determine the crack growth rate.
In this analysis, a mild steel X-65 pipe was used with variations in crack length (c/nR) and pipe thickness. The results showed that the deeper the crack, the greater the ΔK value, while the thicker the pipe, the slower the crack growth rate. This is shown in the 20 mm-thick pipe with c/nR = 0.04, where a 1% increase in crack growth resulted in an average increase in ΔK of 14.32%. Meanwhile, for the 40 mm-thick pipe with c/nR = 0.04, a 1% increase in crack growth resulted in an average increase in ΔK of 8.68%. In addition, the crack length (c/nR) affects the Stress Intensity Factor at the crack front. The longer the crack, the faster the crack growth rate. For the 20 mm-thick pipe with c/nR = 0.04, the increase in ΔK was 14.32%; with c/nR = 0.1, the increase in ΔK was 21.82%; with c/nR = 0.3, the increase in ΔK was 34.47%; and with c/nR = 0.4, the increase in ΔK was 34.82%. This is consistent with the theory of crack growth and failure, in which a crack continues to propagate until the pipe reaches fracture.
| Item Type: | Thesis (Other) |
|---|---|
| Additional Information: | 620.112 6 Uto a |
| Uncontrolled Keywords: | outer circumferential crack, stress intensity factor, pipa mild steel, metode elemen hingga, outer circumferential crack, stress intensity factor, mild steel pipe, metode elemen hingga |
| Subjects: | V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM163 Hulls (Naval architecture) |
| Divisions: | Faculty of Marine Technology (MARTECH) > Marine Engineering > 36202-(S1) Undergraduate Thesis |
| Depositing User: | magang . |
| Date Deposited: | 08 Oct 2026 02:36 |
| Last Modified: | 08 Oct 2026 02:36 |
| URI: | http://repository.its.ac.id/id/eprint/145422 |
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