Analisis Local Buckling Pelat Trapesoidal Pada Extension Grillage Saat Proses Load-Out Menggunakan SPMT

Shafadillah, Muhammad Daffa (2026) Analisis Local Buckling Pelat Trapesoidal Pada Extension Grillage Saat Proses Load-Out Menggunakan SPMT. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Proses load-out struktur lepas pantai menggunakan Self Propelled Modular Transporter (SPMT) membutuhkan sistem pendukung berupa grillage dan extension grillage untuk menjamin distribusi beban yang aman. Pada praktiknya, extension grillage sering bekerja dalam kondisi semi-kantilever sehingga rentan mengalami local buckling, khususnya pada pelat dengan geometri tidak prismatik. Penelitian ini bertujuan untuk mengevaluasi perilaku local buckling pada pelat trapesoidal extension grillage selama proses load-out menggunakan SPMT. Faktor beban kritis yang diperoleh dari analisis eigenvalue buckling adalah sebesar 14,91 × 10⁶ N, sementara beban kerja pasca-hidrolik tercatat sebesar, yang mengindikasikan bahwa struktur telah melampaui kondisi buckling elastis. Studi parametrik menunjukkan bahwa peningkatan tapering ratio (Tr) dari 0,5 hingga 2,5 pada nilai normalized plate length (α) konstan menyebabkan kenaikan koefisien buckling (k) dari sekitar 3,4 menjadi 4,3. Sebaliknya, peningkatan nilai α dari 0,25 hingga 2,0 pada Tr konstan sebesar 1,02 menyebabkan penurunan nilai k dari sekitar 4,1 menjadi nilai asimtot di kisaran 3,5. Hasil ini menegaskan bahwa kelangsingan pelat dan tingkat tapering memiliki pengaruh signifikan terhadap kestabilan pelat trapesoidal. Berdasarkan hasil tersebut, dapat disimpulkan bahwa local buckling pada extension grillage dipengaruhi secara dominan oleh parameter geometri pelat, khususnya normalized plate length dan tapering ratio. Penambahan stiffener pada extension grillage menunjukkan peningkatan signifikan terhadap kestabilan struktur. Hal ini ditunjukkan oleh meningkatnya nilai beban kritis buckling serta perubahan pola deformasi yang semula terlokalisasi menjadi lebih menyebar. Distribusi tegangan von Mises setelah penambahan stiffener tidak lagi terkonsentrasi pada satu titik kritis, melainkan terdistribusi secara lebih merata pada area pelat dan stiffener. Kondisi ini mengindikasikan bahwa stiffener berperan efektif dalam meningkatkan kekakuan lokal pelat, menunda terjadinya instabilitas elastis, serta mengurangi risiko buckling lokal yang bersifat tiba-tiba.
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The load-out process of offshore structures using a Self-Propelled Modular Transporter (SPMT) requires a supporting system in the form of grillage and extension grillage to ensure safe load distribution. In practice, the extension grillage often operates under semi-cantilever conditions, making it susceptible to local buckling, particularly in plates with non-prismatic geometry. This study aims to evaluate the local buckling behavior of trapezoidal plates in extension grillage during the SPMT load-out process. The critical load obtained from eigenvalue buckling analysis was 14.91 × 10⁶ N, while the post-hydraulic working load exceeded this value, indicating that the structure had surpassed the elastic buckling condition. A parametric study showed that increasing the tapering ratio (Tr) from 0.5 to 2.5 at a constant normalized plate length (α) resulted in an increase in the buckling coefficient (k) from approximately 3.4 to 4.3. Conversely, increasing α from 0.25 to 2.0 at a constant Tr of 1.02 caused a reduction in k from approximately 4.1 to an asymptotic value of around 3.5. These results confirm that plate slenderness and the degree of tapering have a significant influence on the stability of trapezoidal plates. Based on these findings, it can be concluded that local buckling in extension grillage is predominantly governed by plate geometric parameters, particularly the normalized plate length and tapering ratio. The addition of stiffeners to the extension grillage demonstrates a significant improvement in structural stability, as indicated by an increase in the critical buckling load and a change in deformation patterns from highly localized to more distributed behavior. After stiffener installation, the von Mises stress distribution is no longer concentrated at a single critical location but is more evenly distributed across the plate and stiffeners. This condition indicates that stiffeners effectively enhance local plate stiffness, delay the onset of elastic instability, and reduce the risk of sudden local buckling.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Buckling Lokal, Pelat Trapesoidal, Grillage Tambahan, SPMT, Metode Elemen Hingga, Local Buckling, Trapezoidal Plate, Extension Grillage, SPMT, Finite Element Method.
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC1665 Offshore structures--Materials.
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Muhammad Daffa Shafadillah
Date Deposited:	05 Feb 2026 05:23
Last Modified:	05 Feb 2026 05:23
URI:	http://repository.its.ac.id/id/eprint/132177

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