Kuantifikasi Besaran dan Distribusi Tegangan Sisa Daerah Pertemuan Pengaku-Badan-Sayap pada Elemen Link Struktur Rangka Baja Berpengaku Eksentrik (SRBE) dengan Metode Difraksi Neutron
Keywords:
Daerah k, Tegangan sisa (residual stress), Link, Neutron diffraction, Struktur Rangka Baja Berpengaku Eksentrik (SRBE).Abstract
Abstrak. Penelitian ini menfokuskan kajian secara eksperimental terhadap besaran dan distribusi tegangan sisa yang dihasilkan dari proses pengelasan di dan sekitar daerah k dari elemen link. Pengukuran dilakukan dengan Metode Difraksi Neutron menggunakan alat Difraktometer Neutron DN1-M PSTBM BATAN. Sebanyak 15 titik dengan 45 arah pengukuran dilakukan di daerah k dalam arah normal, transversal maupun longitudinal. Hasil eksperimen menunjukkan besaran tegangan sisa tarik sebesar 185 Mpa dan 160 Mpa dalam arah longitudinal dan transversal searah weld toe pengelasan antara badan dan sayap dengan luasan daerah tarik 8 kali dari tebal flange. Untuk pengelasan tegak lurus weld toe diperoleh tegangan sisa tarik sebesar 162 Mpa dan 145 Mpa dalam arah longitudinal dan transversal dengan luas daerah tarik 4 kali dari tebal flange. Besarnya tegangan sisa tarik dan lebarnya daerah tarik mengindikasi daerah k merupakan daerah rawan terjadinya awal dari crack yang dapat menurunkan kinerja dari link. Membuat gap pengelasan antara pengaku dengan flange selebar 4 s/d 5 kali tebal flange dapat meningkatkan kinerja dari link karena dapat meminimalkan besaran dan distribusi tegangan sisa tarik.Abstract. This research focused on the experimental study on the residual stress magnitude and distribution resulted from the welding process in and around the k area of the link element. The measurement was done with the Neutron Diffraction Method using the Neutron Diffractometer DN1-M PSTBM BATAN. A number of 15 points with 45 measurement directions were conducted on the k area in normal, transversal and longitudinal directions. The result of the experiment showed 185 Mpa and 160 Mpa residual stress magnitude in longitudinal and transversal directions in the same directions with the weld toe welding between the web and flange with the extent of the stress area 8 times of the flange thickness. The perpendicular welding of the weld toe resulted in 162 Mpa and 145 Mpa residual stresses in longitudinal and transversal directions with 4 times stress area extent from the flange thickness. The residual stress magnitude and the width of stress area indicated the k area as a vulnerable area to the initial crack occurrence, which may decrease the link performance. Making a welding gap 4 to 5 times of the flange thickness between the stiffeners and the flange may increase the link performance because it may minimize the residual stress magnitude and distribution.
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