Pemodelan Numerik Material Anisotropi Nonlinear Pada Panel Komposit Laminasi Kapal Akibat Beban Kombinasi

Dafiq, Mahirun (2026) Pemodelan Numerik Material Anisotropi Nonlinear Pada Panel Komposit Laminasi Kapal Akibat Beban Kombinasi. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Struktur panel lambung kapal berbahan komposit laminasi kerap menerima kombinasi beban statis seperti tarik, tekan, bending, geser, dan puntir secara bersamaan. Kombinasi beban ini menghasilkan distribusi tegangan yang kompleks akibat sifat anisotropi material komposit yang bergantung pada arah serat, serta berpotensi menimbulkan perilaku nonlinear akibat kerusakan progresif pada matriks maupun serat. Penelitian ini bertujuan mengembangkan model numerik material anisotropi nonlinear pada panel komposit laminasi kapal menggunakan Metode Elemen Hingga berbasis perangkat lunak ABAQUS dengan bantuan user subroutine UMAT (User Material), serta menganalisis pengaruh beban kombinasi terhadap distribusi tegangan, beban maksimum (ultimate load), dan respons struktural panel. Subroutine UMAT diprogram menggunakan kriteria kegagalan Hashin tiga dimensi yang dilengkapi skema regulasi viskos dan pembatasan degradasi kekakuan untuk menjaga konvergensi analisis nonlinear. Model divalidasi terhadap data eksperimen three-point bending dari penelitian terdahulu dan menghasilkan nilai error di bawah 5%, dengan error pada ultimate load sebesar 1,2%, sehingga metode pemodelan dinyatakan valid. Analisis selanjutnya dilakukan pada model panel sisi kapal berpenegar dengan variasi jumlah laminasi (6 dan 8 lapisan), arah serat (45° dan 90°), serta kondisi batas (fixed support dan simply support) terhadap enam jenis pembebanan kombinasi. Hasil analisis menunjukkan bahwa arah serat 90° lebih optimal menahan beban yang searah dengannya, sedangkan arah serat 45° lebih unggul dalam menahan beban geser dan mencegah kegagalan akibat tekuk. Kondisi batas fixed support secara umum menghasilkan ultimate load lebih tinggi dibandingkan simply support, dan penambahan jumlah laminasi
meningkatkan kapasitas beban maksimum panel. Evaluasi kriteria kegagalan Hashin menunjukkan bahwa kegagalan matriks terjadi lebih awal dibandingkan kegagalan serat, dengan kegagalan fiber compression yang paling kritis terkonsentrasi pada bagian pembujur.
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Ship hull structures made of laminated composite material, particularly side panels, operationally experience combined static loads—tension, compression, bending, shear, and torsion—acting simultaneously. This combined loading produces complex stress distributions due to the anisotropic properties of composite materials, which are highly dependent on fiber orientation, and may induce nonlinear behavior caused by progressive damage in either the matrix or the fiber. This study aims to develop a numerical model of a nonlinear anisotropic material for ship composite laminate panels using the Finite Element Method in ABAQUS software, assisted by a User Material (UMAT) subroutine, and to analyze the effect of combined loading on stress distribution, ultimate load, and the structural response of the panel. The UMAT subroutine was programmed based on the three-dimensional Hashin failure criteria, incorporating viscous regularization and a stiffness degradation cap to maintain convergence during nonlinear analysis. The model was validated against three-point bending experimental data from previous research, yielding errors below 5%, with an ultimate load error of only 1.2%, confirming the validity of the modeling method. Further analysis was conducted on a stiffened ship side panel model with variations in the number of laminate layers (6 and 8), fiber orientation (45° and 90°), and boundary conditions (fixed support and simply supported) under six types of combined loading. The results show that a 90° fiber orientation is more effective in resisting loads aligned with its direction, while a 45° orientation performs better in resisting shear loads and preventing buckling-induced failure. Fixed support boundary conditions generally produced higher ultimate loads than simply supported conditions, and increasing the number of laminate layers improved the panel's maximum load capacity. Evaluation using the Hashin failure criteria revealed that matrix failure occurred earlier than fiber failure, with the
most critical fiber compression failure concentrated on the stiffener.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Anisotropi Nonlinear, Beban Kombinasi, Metode Elemen Hingga, Subroutin UMAT, Combined Loading, Finite Element Method, Nonlinear Anisotropy, Subroutine UMAT
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA418.9 Composite materials. Laminated materials. V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM156 Naval architecture V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM163 Hulls (Naval architecture)
Divisions:	Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36201-(S1) Undergraduate Thesis
Depositing User:	Mahirun Dafiq
Date Deposited:	04 Aug 2026 08:50
Last Modified:	04 Aug 2026 08:51
URI:	http://repository.its.ac.id/id/eprint/143280

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