Studi Numerik Sistem Constrained Layer Damping (CLD) Pada Lantai Kereta Api Untuk Peningkatan Kenyamanan Penumpang

Santoso, Jason Samuel (2025) Studi Numerik Sistem Constrained Layer Damping (CLD) Pada Lantai Kereta Api Untuk Peningkatan Kenyamanan Penumpang. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini mengkaji secara numerik efisiensi sistem Constrained Layer Damping (CLD) yang diterapkan pada lantai kereta api sebagai upaya peningkatan kenyamanan penumpang. Sistem CLD bekerja mendisipasikan energi getaran melalui mekanisme deformasi geser pada lapisan viskoelastis yang diapit antara struktur dasar lantai kereta (base plate) dan lapisan pembatas kaku (constraining layer). Parameter desain yang divariasikan meliputi jenis material viskoelastis (Butyl Rubber dan Bitumen Rubber), ketebalan viscoelastic layer (1, 2, dan 3 mm), serta ketebalan constraining layer aluminium (1, 2, dan 3 mm), menghasilkan 18 konfigurasi variasi yang dievaluasi. Karakteristik peredaman setiap konfigurasi CLD dievaluasi menggunakan metode analitik Ross-Kerwin-Ungar (RKU) untuk memperoleh loss factor sistem (ηc), yang kemudian diverifikasi terhadap hasil simulasi elemen hingga pada perangkat lunak ANSYS melalui metode half-power bandwidth. Hasil verifikasi menunjukkan selisih antara kedua metode berkisar 1,72% hingga 10,38%, mengonfirmasi validitas formula RKU sebagai alat estimasi ηc yang andal. Respons dinamis sistem kereta api selanjutnya disimulasikan menggunakan model state-space pada MATLAB dengan eksitasi berupa data ketidakrataan lintasan nyata yang diproses melalui interpolasi PCHIP. Kenyamanan penumpang dievaluasi menggunakan Sperling Index (Wz) dan Mean Comfort Index (Nmvz) berdasarkan standar internasional EN 12299. Hasil simulasi menunjukkan bahwa seluruh 18 konfigurasi CLD berhasil mempertahankan nilai Nmvz dalam kategori 'Nyaman' menurut EN 12299, dengan rentang Nmvz antara 1,4667 (konfigurasi Bitumen tv3-tc3) hingga 1,9218 (konfigurasi Butyl tv1-tc1), setara reduksi maksimum sebesar 23,68%. Analisis pengaruh parameter menunjukkan bahwa ketebalan constraining layer (tcl) merupakan parameter desain yang paling dominan, dengan reduksi Nmvz mencapai 19,93–20,78% untuk peningkatan tcl dari 1 mm ke 3 mm. Sebaliknya, pengaruh ketebalan viscoelastic layer (tvis) bersifat diminishing return, dengan manfaat yang semakin mengecil seiring bertambahnya tcl. Perbedaan performa antara Butyl Rubber dan Bitumen Rubber relatif kecil (ΔWz = 0,003–0,009), sehingga kedua material dapat dianggap setara secara praktis. Lebih lanjut, ditemukan hubungan korelasi kuat antara ηc dan Nmvz yang dapat direpresentasikan dengan model regresi power law Nmvz = 1,129 × ηc^(−0,1685) dengan koefisien determinasi R² = 0,956, yang dapat digunakan sebagai nomogram desain awal untuk menentukan konfigurasi CLD secara efisien tanpa simulasi penuh.
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This study numerically investigates the efficiency of Constrained Layer Damping (CLD) systems applied to railway car floors as a means of improving passenger comfort. The CLD system dissipates vibration energy through shear deformation of a viscoelastic layer sandwiched between the floor base plate and a rigid constraining layer. The design parameters varied include the type of viscoelastic material (Butyl Rubber and Bitumen Rubber), viscoelastic layer thickness (1, 2, and 3 mm), and aluminum constraining layer thickness (1, 2, and 3 mm), yielding 18 configurations for evaluation. The damping characteristics of each CLD configuration were evaluated using the Ross-Kerwin-Ungar (RKU) analytical method to obtain the system loss factor (ηc), which was subsequently verified against finite element simulation results from ANSYS software through the half-power bandwidth method. Verification results showed discrepancies between the two methods ranging from 1.72% to 10.38%, confirming the validity of the RKU formula as a reliable estimator of ηc. The dynamic response of the railway system was then simulated using a state-space model in MATLAB, with excitation derived from real track irregularity measurement data processed through PCHIP interpolation. Passenger comfort was evaluated using the Sperling Index (Wz) and Mean Comfort Index (Nmvz) in accordance with the EN 12299 international standard. Simulation results demonstrate that all 18 CLD configurations successfully maintained Nmvz values within the 'Comfortable' category according to EN 12299, with Nmvz ranging from 1.4667 (Bitumen tv3-tc3 configuration) to 1.9218 (Butyl tv1-tc1 configuration), equivalent to a maximum reduction of 23.68%. Parametric analysis reveals that constraining layer thickness (tcl) is the most dominant design parameter, achieving Nmvz reductions of 19.93–20.78% as tcl increases from 1 mm to 3 mm. Conversely, the influence of viscoelastic layer thickness (tvis) exhibits a diminishing return pattern, with progressively smaller benefits as tcl increases. The performance difference between Butyl Rubber and Bitumen Rubber is marginal (ΔWz = 0.003–0.009), rendering both materials practically equivalent. Furthermore, a strong correlation between ηc and Nmvz was identified and represented by the power law regression model Nmvz = 1.129 × ηc^(−0.1685) with a coefficient of determination R² = 0.956, which serves as a preliminary design nomogram for efficiently determining optimal CLD configurations without full-scale simulation.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Constrained Layer Damping (CLD), getaran kereta api, Mean Comfort Index, Sperling Index, EN 12299, metode RKU, power law ======================================================================================================================== Constrained Layer Damping (CLD), railway vibration, Mean Comfort Index, Sperling Index, EN 12299, RKU method, power law.
Subjects:	T Technology > TF Railroad engineering and operation > TF193 Estimates, costs, etc. T Technology > TF Railroad engineering and operation > TF872 Rails (Track) T Technology > TJ Mechanical engineering and machinery > TJ230 Machine design
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User:	Jason Samuel Santoso
Date Deposited:	30 Jul 2026 06:27
Last Modified:	30 Jul 2026 06:27
URI:	http://repository.its.ac.id/id/eprint/140427

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