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Journal : Indonesian Journal of Aerospace

A Corotational Formulation For Geometrically Nonlinear Dynamics of 2D Flexible Beams Andria, Novi; Zuhal, Lavi Rizki; Muhammad, Hari; Gunawan, Leonardo
Indonesian Journal of Aerospace Vol. 22 No. 2 (2024): Indonesian Journal Of Aerospace
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/ijoa.2024.8949

Abstract

A simple and efficient 2D corotational formulation for dynamic analysis of geometrically nonlinear flexible beam is presented in this paper. The corotational approach can easily facilitate the evaluation of internal elactic forces by introducing an element frame to separate rigid body motion and the deformational part. In the present study, the Euler-Bernoulli beam models with simple geometric stiffness matrix is employed and Newmark’s implicit time-stepping scheme with iterative predictor-corrector algorithm is adopted. The validity and efficiency of the present corotational formulation are verified by simulating three numerical examples. Despite its simple numerical implementation, simulation results confirms that the proposed formulation is highly accurate and efficient in simulating flexible beams undergoing large deformation.
Design Optimization of A Conventional Rocket Nozzle Using Coupled Thermo-Structural Analysis Saputra, M. Dito; Andria, Novi
Indonesian Journal of Aerospace Vol. 19 No. 2 (2021)
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30536/j.jtd.2021.v19.a3570

Abstract

Thrust in a rocket is gained by expelling the combustion gas through a nozzle.  This rocket nozzle is a vital component during the conversion of chemical energy into kinetic energy. Consequently, it is exposed to extreme temperature and pressure resulted from gas combustion. Therefore to ensure a successful rocket operation, the nozzle must be able to maintain structural integrity when exposed to such environment. On the other hand, its structural weight must be kept minimum to reduce the overall weight of the rocket. Due to these circumstances, the nozzle design phase is very important since the nozzle significantly affects the whole rocket performance. LAPAN is currently developing some solid propellant based rocket. Each rocket’s nozzle is still designed using conventional configuration, consisting of a metal case and graphite insert. The nozzle relies on a thick structure geometry to maintain structural integrity. This approach induces a heavy-weight nozzle that burdens the rocket performance. This paper is attempted to optimize LAPAN’s conventional solid rocket nozzle design. A series of procedures are proposed to generate a lighter nozzle design. RX-450 rocket’s nozzle will be used as the studied model in this paper. Coupled thermo-structural analysis forms the main procedure to evaluate the proposed nozzle geometry structural integrity. The study succesfully provided an optimized nozzle geometry with sufficient strength and reduced weight.
METODA COROTATIONAL BEAM 2D UNTUK ANALISIS STATIK STRUKTUR NONLINIER GEOMETRIK Andria, Novi; Zuhal, Lavi R.; Gunawan, Leonardo; Muhammad, Hari
Indonesian Journal of Aerospace Vol. 17 No. 1 Juni (2019): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30536/j.jtd.2019.v17.a3117

Abstract

Makalah ini membahas sebuah metoda corotational beam dua dimensi (CBM 2D) yang dapat digunakan untuk analisis statik struktur yang nonlinier secara geometri. Kombinasi antara formulasi corotational beam dan Euler-Bernouli beam Theory (EBT) membuat implementasi numerik metoda ini menjadi sangat sederhana dengan beban komputasi yang rendah sehingga sangat praktis untuk diaplikasikan. Akurasi dan efisiensi metoda ini terverifikasi melalui beberapa uji numerik yang dilakukan pada beberapa model uji yang terdapat pada literatur. Metoda ini pun mampu memberikan hasil yang akurat untuk kasus extensible beam dan struktur beam yang dibebani follower load. Hasil penelitian ini memverifikasi validitas, efisiensi, dan kepraktisan dari metoda yang dikembangkan.
ANALISIS FAKTOR KOREKSI PERHITUNGAN TRAYEKTORI ROKET LAPAN, STUDI KASUS: RX200 LAPAN-ORARI (CORRECTION FACTOR ANALYSIS OF TRAJECTORY CALCULATION OF LAPAN'S ROCKET, CASE STUDY: RX-200 LAPAN-ORARI ROCKET) Andria, Novi
Indonesian Journal of Aerospace Vol. 11 No. 1 Juni (2013): Jurnal Teknologi Dirgantara
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Selama ini perbedaan profil trayektori antara hasil simulasi dengan hasil uji terbang roket-roket Lapan masih cukup besar. Upaya perbaikan perhitungan trayektori roket dikonsentrasikan pada tiga parameter yakni nilai koefisien gaya hambat (Cd), nilai kecepatan awal (Vi) dan penyekalaan gaya dorong. Perhitungan trayektori dilakukan menggunakan simulator trayektori roket berbasiskan Simulink yang dikembangkan oleh peneliti dinamika terbang - Lapan. Model RX 200 LAPAN-ORARI 2 digunakan sebagai wahana uji. Dibandingkan dengan hasil uji terbang, error terkecil perhitungan trayektori terdapat pada simulasi dengan menggunakan nilai Vi 0 m/s dengan menyekalakan gaya dorong sebesar 97% gaya dorong yang diperoleh dari uji statik tanpa adanya perubahan nilai Cd. Penelitian ini menyimpulkan bahwa penyebab utama tidak akuratnya perhitungan trayektori roket RX 200 LAPAN-ORARI adalah bukan karena tidak tepatnya nilai Cd yang di-input-kan. Keakurasian perhitungan trayektori dapat ditingkatkan dengan menetapkan nilai kecepatan awal seperti kondisi nyata yakni 0 m/s dan nilai gaya dorong yang tepat dengan menambah frekuensi uji statik untuk motor roket sejenis.