Santosa, Sigit Puji
Faculty of Mechanical and Aerospace Engineering, National Center for Sustainable Transportation Technology, Institut Teknologi Bandung

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Journal : Mesin

The Influence of Forming Effects on The Bending Crush Behavior of Top-Hat Thin–Walled Beams Santosa, Sigit Puji; Nhat Vu, Nguyen Van; Gunawan, Leonardo; Jusuf, Annisa
Mesin Vol 25, No 2 (2016)
Publisher : Mesin

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Abstract

This paper presents a study on the effects of forming process of a top–hat thin–walled beams to its bending crush resistance under dynamic bending load. The thin–walled beam was formed using a one step deep drawing. HyperForm software simulated the forming process and mapped its effects such as thickness variations and residual plastic strains in to the crash analysis models. Then the dynamic bending crush analysis was carried out using LS–DYNA by using the geometry and materials data obtained from the forming analysis results. For each material model, the analyses were carried out for model with and without the forming effects. The bending crush behavior of the top–hat thin–walled beams were then analyzed to compare between the simulations with and without forming effects. The results show that by incorporating the effect of forming process, the bending crush resistance of the thin–walled  beams is increase by 4.7%. The introduction of strain rates to the material model increases even further on the bending crush resistance of the thin–walled  beam.
Sifat Mekanik Packaging Kertas Berbahan Dasar Selulosa Alga Cladophora Mardiyati, Mardiyati; Steven, Steven; Suratman, Rochim; Santosa, Sigit Puji
Mesin Vol 27, No 1 (2018)
Publisher : Mesin

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Abstract

Alga cladophora merupakan salah satu alga yang banyak tumbuh di pesisir pantai Indonesia. Alga cladophora memiliki kandungan selulosa yang cukup tinggi sehingga sangat berpotensi untuk dimanfaatkan sebagai bahan baku material packaging kertas. Tujuan dari penelitian ini adalah mempelajari sifat mekanik kertas yang berbahan dasar selulosa alga cladophora. Pada penelitian ini, selulosa alga cladophora diekstraksi melalui beberapa tahapan proses yang meliputi proses alkalisasi dan proses hidrolisis. Proses alkalisasi dilakukan dengan merefluks alga cladophora didalam larutan NaOH (1%, 5%, 10%, 15% dan 17.5%) pada temperatur 100 ? selama 2 jam. Proses hidrolisis dilakukan dengan merefluks alga cladophora hasil alkalisasi didalam larutan asam sulfat 1 M pada temperatur 100 ? selama 2 jam. Proses pembuatan kertas dilakukan dengan metode solution casting. Kandungan selulosa diukur dengan menggunakan metode Chesson-Datta. Sifat mekanik dari kertas selulosa alga cladophora diukur dengan pengujian tarik. Dari hasil pengukuran kandungan selulosa dapat disimpulkan bahwa selulosa yang diekstrasi dengan menggunakan larutan NaOH 17.5% memiliki tingkat kemurnian yang paling tinggi, yakni 94. 76%. Selulosa yang diekstraksi dengan menggunakan larutan NaOH 17.5% menghasilkan kertas dengan permukaan yang paling halus serta memiliki kekuatan tarik dan kekakuan yang paling tinggi dibandingkan dengan kertas lainnya yang dihasilkan dalam penelitian ini, yakni 57.68 MPa dan 10.12 GPa.
Numerical Study of Experiment Setup for Aluminum Foam Sandwich Construction Subjected to Blast Load Pratomo, Arief Nur; Santosa, Sigit Puji; Gunawan, Leonardo; Putra, Ichsan Setya
Mesin Vol 27, No 1 (2018)
Publisher : Mesin

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Abstract

In the designing an armored fighting vehicle (AFV), blastworthy construction to protect military personnel from landmines explosion is urgently needed. This is due to a large number of fatalities of army personnel in the state conflict zones. To achieve this blastworthy construction, the design of AFV floor structures needs to be able to sustain structural intrusion with lower dynamic acceleration against blast load. The blastworthy structures can be achieved through absorbing the blast impact load by using an aluminum foam sandwich (AFS) construction. During the design iteration process, a good correlation between numerical simulation and blast impact experiment is required. In this study, an experimental setup to assess the AFS construction for blast load performance evaluation was introduced. This study is started with an evaluation of jigs and fixtures structural strength, load cell structure requirement, and data acquisition to record maximum displacement, maximum acceleration, and reaction force in the load cells. From the evaluation, it was found that the jig and fixture structural configuration requires high load retention at the bolt joint location to avoid high stress concentration. For the load cell structure, it is recommended to place the load cell position in the pure axial stress direction so that there is no plastic deformation interference with the instrumentation. The data acquisitions will record the acceleration and reaction force of the AFS construction. The simulation results are also used to design the load cell and to select the accelerometer capability range. This study is expected to provide a robust experimental data during blast impact load testing of blastworthy AFS floor structure. 
The Influence of Forming Effects on The Bending Crush Behavior of Top-Hat Thin–Walled Beams Sigit Puji Santosa; Nguyen Van Nhat Vu; Leonardo Gunawan; Annisa Jusuf
Mesin Vol. 25 No. 2 (2016)
Publisher : Mesin

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

Abstract

This paper presents a study on the effects of forming process of a top–hat thin–walled beams to its bending crush resistance under dynamic bending load. The thin–walled beam was formed using a one step deep drawing. HyperForm software simulated the forming process and mapped its effects such as thickness variations and residual plastic strains in to the crash analysis models. Then the dynamic bending crush analysis was carried out using LS–DYNA by using the geometry and materials data obtained from the forming analysis results. For each material model, the analyses were carried out for model with and without the forming effects. The bending crush behavior of the top–hat thin–walled beams were then analyzed to compare between the simulations with and without forming effects. The results show that by incorporating the effect of forming process, the bending crush resistance of the thin–walled beams is increase by 4.7%. The introduction of strain rates to the material model increases even further on the bending crush resistance of the thin–walled beam.
Numerical Study of Experiment Setup for Aluminum Foam Sandwich Construction Subjected to Blast Load Arief Nur Pratomo; Sigit Puji Santosa; Leonardo Gunawan; Ichsan Setya Putra
Mesin Vol. 27 No. 1 (2018)
Publisher : Mesin

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

Abstract

In the designing an armored fighting vehicle (AFV), blastworthy construction to protect military personnel from landmines explosion is urgently needed. This is due to a large number of fatalities of army personnel in the state conflict zones. To achieve this blastworthy construction, the design of AFV floor structures needs to be able to sustain structural intrusion with lower dynamic acceleration against blast load. The blastworthy structures can be achieved through absorbing the blast impact load by using an aluminum foam sandwich (AFS) construction. During the design iteration process, a good correlation between numerical simulation and blast impact experiment is required. In this study, an experimental setup to assess the AFS construction for blast load performance evaluation was introduced. This study is started with an evaluation of jigs and fixtures structural strength, load cell structure requirement, and data acquisition to record maximum displacement, maximum acceleration, and reaction force in the load cells. From the evaluation, it was found that the jig and fixture structural configuration requires high load retention at the bolt joint location to avoid high stress concentration. For the load cell structure, it is recommended to place the load cell position in the pure axial stress direction so that there is no plastic deformation interference with the instrumentation. The data acquisitions will record the acceleration and reaction force of the AFS construction. The simulation results are also used to design the load cell and to select the accelerometer capability range. This study is expected to provide a robust experimental data during blast impact load testing of blastworthy AFS floor structure. 
Sifat Mekanik Packaging Kertas Berbahan Dasar Selulosa Alga Cladophora Mardiyati Mardiyati; Steven Steven; Rochim Suratman; Sigit Puji Santosa
Mesin Vol. 27 No. 1 (2018)
Publisher : Mesin

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

Abstract

Alga cladophora merupakan salah satu alga yang banyak tumbuh di pesisir pantai Indonesia. Alga cladophora memiliki kandungan selulosa yang cukup tinggi sehingga sangat berpotensi untuk dimanfaatkan sebagai bahan baku material packaging kertas. Tujuan dari penelitian ini adalah mempelajari sifat mekanik kertas yang berbahan dasar selulosa alga cladophora. Pada penelitian ini, selulosa alga cladophora diekstraksi melalui beberapa tahapan proses yang meliputi proses alkalisasi dan proses hidrolisis. Proses alkalisasi dilakukan dengan merefluks alga cladophora didalam larutan NaOH (1%, 5%, 10%, 15% dan 17.5%) pada temperatur 100 ℃ selama 2 jam. Proses hidrolisis dilakukan dengan merefluks alga cladophora hasil alkalisasi didalam larutan asam sulfat 1 M pada temperatur 100 ℃ selama 2 jam. Proses pembuatan kertas dilakukan dengan metode solution casting. Kandungan selulosa diukur dengan menggunakan metode Chesson-Datta. Sifat mekanik dari kertas selulosa alga cladophora diukur dengan pengujian tarik. Dari hasil pengukuran kandungan selulosa dapat disimpulkan bahwa selulosa yang diekstrasi dengan menggunakan larutan NaOH 17.5% memiliki tingkat kemurnian yang paling tinggi, yakni 94. 76%. Selulosa yang diekstraksi dengan menggunakan larutan NaOH 17.5% menghasilkan kertas dengan permukaan yang paling halus serta memiliki kekuatan tarik dan kekakuan yang paling tinggi dibandingkan dengan kertas lainnya yang dihasilkan dalam penelitian ini, yakni 57.68 MPa dan 10.12 GPa.
Analisis Struktur Octet-Truss Lattice Sebagai Struktur Penyerap Energi Pada Subfloor Helikopter I Ketut Adi Sentana Putra; Sigit Puji Santosa; Tatacipta Dirgantara; Annisa Jusuf
Mesin Vol. 27 No. 2 (2018)
Publisher : Mesin

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Abstract

Semakin meningkatnya penggunaan helikopter dalam transportasi udara menyebabkan semakin meningkatnya peluang terjadinya kecelakaan. Sebagian besar kecelakaan pada helikopter adalah jatuh dan merusak bagian bawah struktur badan helikopter (subfloor) akibat beban dinamik. Untuk meningkatkan keamanan dan mengurangi resiko terjadinya cedera fatal pada penumpang perlu dilakukan kajian crashworthiness pada helikopter.Salah satu cara manajemen energi serap pada struktur helikopter terhadap tabrakan adalah dengan mengoptimalkan struktur penyerap energi. Peningkatan energi serap dapat dilakukan dengan menggunakan geometri lattice sebagai struktur penyerap energi. Struktur lattice merupakan solusi yang menjanjikan untuk dipergunakan sebagai struktur penyerap energi impak. Tugas akhir ini difokuskan untuk melakukan studi mengenai karakteristik respon octet-truss lattice ketika dikenakan beban impak dan pengaplikasiannya pada struktur subfloor helikopter dengan metode elemen hingga. Analisis  numerik untuk studi perbandingan konfigurasi struktur cruciform, struktur octet-truss lattice bertumpuk uniform dengan octet-truss lattice bertumpuk double taper sebagai struktur penyerap energi. Dengan adanya teknologi manufaktur aditif, struktur lattice dapat dengan mudah diproduksi menggunakan teknik selective laser sintering (SLS). Material yang digunakan dalam simulasi numerik berupa paduan alumunium AlSi-12 hasil manufaktur SLS. Hasil konfigurasi lattice akan digunakan pada subfloor helikopter dan  dibandingkan dengan struktur cruciform. Setelah dilakukan simulasi numerik dengan metode elemen hingga akan dilihat struktur mana yang mempunyai specific energy absorb tertinggi . Hasil ini menunjukkan bahwa struktur lattice dengan konfigurasi double taper memiliki specific energy absorb tetinggi sebesar 34.44 kJ/kg. Dari hasil pemodelan elemen hingga didapat konfigurasi octet-truss lattice dengan double taper memiliki potensi yang besar sebagai struktur penyerap energi dimasa depan.