ANALISA PERILAKU TEGANGAN SISA DAN PERUBAHAN SUDUT DISTORSI PADA SAMBUNGAN TUMPUL DENGAN VARIASI TEBAL PLAT MENGGUNAKAN METODE ELEMEN HINGGA

Studi tentang pemodelan dan perhitungan tegangan sisa akibat pengelasan dilakukan pada sambungan-butt dalam suatu struktur plat datar. Untuk model perhitungan diambil material dengan WPS standard PAL Indonesia dengan data film koefisien 30 , dan angka muai termal 1,3x10-5 /K. Tegangan sisa dihitung berdasarkan iterasi regangan yang timbul akibat distribusi suhu selama pendinginan dari suhu pengelasan menuju temperatur ruang dengan simulasi suhu dalam °K. Perhitungan berdasarkan metode elemen hingga pada daerah las sebesar 2216 °K dengan program ANSYS 9.0 model 3 dimensi. Konsentrasi tegangan dapat diamati pada sambungan pengelasan yang terjadi pada bagian dalam dan permukaan sambungan. Dengan memvariasi tebal plat menghasilkan distribusi tegangan sisa maksimum pada variasi I yakni tebal 2mm dengan harga tegangan total pada bahan las berkisar antara 966 sampai dengan 1740 MPa, sedangkan pada material induk antara 1,5 sampai 580 Mpa, angular distorsinya (2α) sebesar 1,775o dan sudut distorsi bendingnya (β) sebesar 2,57o. Tegangan sisa minimum dialami variasi V yakni dengan tebal 30 mm, dimana tegangan total pada bahan las berkisar antara 151 sampai dengan 272 MPa, sedangkan pada material induk antara 0,02 sampai 151 Mpa, angular distorsinya (2α) sebesar 0,049o dan sudut distorsi bendingnya (β) sebesar 0,031o. Dari perhitungan ini dapat disimpulkan bahwa komputasi perhitungan sisa dapat memprediksi harga rata-rata maupun harga maksimum tegangan sisa yang terjadi akibat konsentrasi tegangan juga distorsi yang menyertainya.

Alt. Description

Study about modeling and calculation of the residual stress on welding process was performed in the Butt junction in a plate structure level off. For the model of calculation taken material from WPS PAL Indonesia standard with coefficient film data is 30 ,and number of thermal expansion is 1,3x10-5 /K. The residual stress was calculated by iteration of the strain which was obtained from the temperature distribution during the cooling process on the welding to the room temperature with temperature simulation in oK. Calculation pursuant to element method till area of welding equal to 2216 ° K with ANSYS 9.0 program 3 dimension of modeling. The stress concentration could be observed at the welded junction which was occurred in the inner and surface junction. With thick variation of plate, yield tension distribution of residual stress maximum at variation I, thick namely 2mm with the price of total tension of welding materials range from 966 up to 1740 MPa, while at mains material among 1,5 until 580 MPa, its distortion angular ( 2α ) equal to 1,775o and its bending distortion angle equal to 2,57o. Residual Stress minimum at variation V, namely thickly 30 mm, where total tension of welding materials range from 151 up to 272 MPa, while at mains material between 0,02 until 151 MPa, its distortion angular ( 2α ) equal to 0,049o and its beding distortion angle equal to 0,031o. Based on the calculation result, it can be concluded that the computation method can predict the average and the maximum of residual stress from the stress concentration.

Contributor	:	Ir Budie santosa, MT
Date Create	:	22/11/2008
Type	:	Text
Format	:	pdf.
Language	:	Indonesian
Identifier	:	ITS-Undergraduate-1234
Collection ID	:	3100008031368
Call Number	:	RSPe 623.843 2 Fir a

Source :
Undergraduate theses, DEPARTMENT OF NAVAL ARCHITECT RSPe 623.843 2 Fir a, 2007

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