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Indonesian Wood as Material for Acoustic Guitars and Violins Indraswari Kusumaningtyas; Subagio Subagio
Wood Research Journal Vol 3, No 1 (2012): Wood Research Journal
Publisher : Masyarakat Peneliti Kayu Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51850/wrj.2012.3.1.11-17

Traditionally, acoustic guitars and violins are made from European woods. Spruce is most preferred for the top plate (soundboard), whereas maple, sycamore and rosewood are often used for the back plate. However, these woods are not easily available in Indonesia. In this paper, we present a study on the suitability of a selection of Indonesian woods, namely acacia, mahogany, pine, sengon and sonokembang, as materials for acoustic guitars and violins. The most important acoustical properties for selecting materials for musical instruments, i.e. the speed of sound, the sound radiation coefficient and the damping factor, were investigated. Furthermore, the performance of pine and mahogany were tested by making them into a violin and a guitar. The vibration frequency spectrum and the damping factor of the top plate were measured. The results show that the acoustical characteristics of mahogany are very close to those of maple and still quite close to those of Indian rosewood, which makes it a very suitable local material for back plates. Pine has quite similar acoustical characteristics to spruce. Although its sound radiation coefficient is slightly lower, its aesthetic appeal and workability makes pine a suitable alternative for top plates. However, instruments with pine top plates exhibit different tonal colour compared to instruments with spruce top plates, due to some differences in the vibration frequency spectrum. Furthermore, the generally higher damping factors of pine and mahogany compared to those of the European woods should be taken into account, because they affect the sustain-time of the generated sound.

Indonesian Wood as Material for Acoustic Guitars and Violins Indraswari Kusumaningtyas; Subagio Subagio
Wood Research Journal Vol 3, No 1 (2012): Wood Research Journal
Publisher : Masyarakat Peneliti Kayu Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51850/wrj.2012.3.1.11-17

Traditionally, acoustic guitars and violins are made from European woods. Spruce is most preferred for the top plate (soundboard), whereas maple, sycamore and rosewood are often used for the back plate. However, these woods are not easily available in Indonesia. In this paper, we present a study on the suitability of a selection of Indonesian woods, namely acacia, mahogany, pine, sengon and sonokembang, as materials for acoustic guitars and violins. The most important acoustical properties for selecting materials for musical instruments, i.e. the speed of sound, the sound radiation coefficient and the damping factor, were investigated. Furthermore, the performance of pine and mahogany were tested by making them into a violin and a guitar. The vibration frequency spectrum and the damping factor of the top plate were measured. The results show that the acoustical characteristics of mahogany are very close to those of maple and still quite close to those of Indian rosewood, which makes it a very suitable local material for back plates. Pine has quite similar acoustical characteristics to spruce. Although its sound radiation coefficient is slightly lower, its aesthetic appeal and workability makes pine a suitable alternative for top plates. However, instruments with pine top plates exhibit different tonal colour compared to instruments with spruce top plates, due to some differences in the vibration frequency spectrum. Furthermore, the generally higher damping factors of pine and mahogany compared to those of the European woods should be taken into account, because they affect the sustain-time of the generated sound.

Evaluasi Kegagalan Cacat Korosi Internal Pipa Minyak Sepinggan Dengan Metode Element Hingga Hery Lesmana; Indraswari Kusumaningtyas
Journal of Mechanical Design and Testing Vol 3, No 1 (2021): Articles
Publisher : Departemen Teknik Mesin dan Industri, Universitas Gadjah Mada

Pipa Sepinggan sudah terkena serangan korosi internal dan perlu dievaluasi agar dapat dioperasikan dengan aman. Evaluasi dengan ASME-B31G level 1 sangat konservatif sehingga bisa jadi kondisi pipa dinilai terlalu rendah dan akhirnya dilakukan perbaikan berbiaya mahal yang tidak perlu. Disamping itu, evaluasi dengan cara ini juga tidak memperhitungkan besar kecilnya lebar korosi. Untuk itu, diperlukan penelitian dengan FEM untuk mengetahui konservatisme penggunaan ASME B31G level 1, termasuk pada variasi lebar korosi, sehingga hasil evaluasi cacat korosi nya dan keputusan apakah pipa ini perlu diperbaiki dapat dihasilkan dengan akurat. Penelitian ini diawali dengan studi literatur, kemudian dilanjutkan dengan pemodelan cacat korosi pada pipa dengan bantuan program Ansys Workbench yang divalidasi dengan data referensi. Model yang tervalidasi kemudian digunakan untuk simulasi efek lebar korosi pada tekanan pecah pipa. Dari hasil simulasi FEM diketahui konservatisme dari ASME-B31G Level 1 dan faktor koreksi yang harus diberikan agar perhitungannya akurat. Selanjutnya pipa Sepinggan dievaluasi dengan metode yang memberikan akurasi tertinggi. Dari hasil penelitian, konservatisme ASME-B31G level 1 memerlukan beberapa faktor koreksi terkait dengan lebar korosinya.

Analisa Perbandingan Kekuatan Profil Padeye Berdasarkan Desain Standara DNV dan BS-EN Studi Kasus: Cargo Carrying Unit Feri Noviantoro; Indraswari Kusumaningtyas
Journal of Mechanical Design and Testing Vol 3, No 2 (2021): Articles
Publisher : Departemen Teknik Mesin dan Industri, Universitas Gadjah Mada

Abaqus Manual Book Version 6.8 (2008) – Getting started with Abaqus (Interactive Edition)ASTM A36/A36M - 14 (2015) – Standard Specification for Carbon Structural SteelBS EN 12079-1:2006 – Offshore containers and associated lifting sets — Part 1: Offshore containers — Design, manufacture and marking.BS EN 12079-2:2006 – Offshore containers and associated lifting sets — Part 2: Lifting sets — Design, manufacture and marking.BY Y. HIGASHIDA, J. D. BURK, AND F. V. LAWRENCE, JR. (1978). StrainControlled Fatigue Behavior of ASTM A36 and A514 Grade F Steels and 5083-0 Aluminum Weld Materials.Bukaka. (2010). Provision of Cargo Carrying Unit Project.Chevron. (2009). MCA – Lifting and Rigging Standard. Houston: Chevron Corporation.Crosby Catalogue (2003) – Crosby Bolt-Type ShacklesDaniela Scorza, Andrea Carpinteri, Sabrina Vantadori (2018). Tension failure assessment at lug hole edges. Department of Engineering & Architecture, University of Parma.DNV No. 2.7-1 2013 – Standard for Certification of Offshore Containers.Gérald Portemont, Julien Berthe, Alain Deudon, François-Xavier Irisarri (2018). Static and dynamic bearing failure of carbon/epoxy composite joints. DMAS, ONERA, University Paris Saclay.Henny Gusti Pramita, Handayanu dan Yoyok Setyo H. (2013). Analisis Struktur Padeye pada Proses Lifting Jacket Empat Kaki dengan Pendekatan Dinamik. Jurusan Teknik Kelautan, Fakultas Teknologi Kelautan, Institut Teknologi Sepuluh Nopember (ITS).Hikmat Saaid Saleh (2016). Ultimate capacity of pad eyes in lifting operations. Faculty of Science and Technology, University of Stavanger.Hoover Ferguson Group, Inc (2018) – Definition of Cargo Carrying UnitsIqbal Gayuh R.M.S, Yeyes M, dan Yoyok S.M. (2016). Analisis Keandalan Struktur Padeye Berdasarkan Konfigurasi Rigging pada Lifting Upper Deck Modul MODEC dengan Pendekatan Dinamik. Jurusan Teknik Kelautan, Fakultas Teknologi Kelautan, Institut Teknologi Sepuluh Nopember (ITS).Roberto Leon. (2018). Journal of Visualized Experiments, Stress-Strain Characteristics of Steels. Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VAT.W. Ling, X.L. Zhao, R. Al-Mahaidi, J.A. Packer (2006). Investigation of block shear tear-out failure in gusset-plate welded connections in structural steel hollow sections and very high strength tubes. Civil Engineerng, Faculty of Civil Engineering, Monash University.

THE MUSICAL ACOUSTICS OF BUNDENGAN Gea O.F. Parikesit; Indraswari Kusumaningtyas
Proceeding IICACS No 2 (2017)
Publisher : Proceeding IICACS

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (689.422 KB)

Bundengan is an Indonesian musical instrument developed by duck herders in Wonosobo, Central Java. Recently the organology of the bundengan has been studied by M. Saâ€™id Abdulloh from ISI Surakarta. We build upon this result and use quantitative measurements and computations to reveal the exact mechanisms of the bundengan strings (see:http://tinyurl.com/Bundengan). Our measurements show that the small bamboo clips attached to the strings is the key element on how the strings generate metallic gong-like sounds. As the string is plucked, the bamboo clips divide the string into several parts, each of them vibrating with different frequencies. This results in non-harmonic spectra, resembling the sounds from metallic instruments. Our computation show in more details how the mass of the bamboo clips determine the string vibrations. Keywords:Bundengan, acoustics, music.

Studi Sifat Keterbasahan pada Material Slumpring Bambu dengan Metode Pengukuran Sudut Kontak Permukaan Ahmad, Yusuf; Kusumaningtyas, Indraswari; Parikesit, Gea Oswah Fatah
Journal of Mechanical Design and Testing Vol 6, No 1 (2024): Articles
Publisher : Department of Mechanical and Industrial Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jmdt.97743

Slumpring merupakan istilah dalam Bahasa Jawa untuk pelepah yang menyelubungi ruas batang bambu. Salah satu pemanfaatan slumpring ini ditemukan pada alat musik bundengan. Sebelum dimainkan oleh musisi, biasanya bundengan dilakukan proses perendaman untuk menghasilkan bunyi yang enak didengar. Selain itu zaman dahulu bundengan ini juga dimanfaatkan sebagai tudung pelindung hujan oleh penggembala bebek. Hal ini membuat interaksi slumpring dan air terlihat unik. Dari informasi tersebut menimbulkan sebuah dugaan bahwa slumpring memiliki dua sifat keterbasahan yaitu hidrofilik berdasarkan perlakuan oleh musisi terhadap bundengandanhidrofobik berdasarkan pemanfaatan bundengan oleh penggembala bebek. Penelitian ini bertujuan untuk memastikan dugaan tersebut dengan menganalisis sudut kontak pada dinding luar dan dinding dalam slumpring. Tidak hanya itu, penelitian ini juga mengukur sudut kontak yang terjadi pada area tengah dan tepi slumpring. Penelitian ini menggunakan peralatan sederhana dan telepon cerdas untuk merekam citra sudut kontak. Analisis citra yang dilakukan menggunakan bantuan perangkat lunak ImageJ. Hasilnya kedua dinding dengan masing-masing sisinya ternyata memiliki sifat hidrofilik. Sudut kontak dinding luar area tengah dan tepi bernilai 60,4±8,4° dan 60,7±12,4° sedangkan sudut kontak dinding dalam area tengah dan tepi bernilai 42,1±9,7° dan 47,5±1,2°.

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