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All Journal Journal of Engineering and Technological Sciences Mesin Jurnal Ilmiah MEA (Manajemen, Ekonomi, dan Akuntansi)
Leonardo Gunawan
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Decision Sciences, Operations Research & Management Economics, Econometrics & Finance Engineering Mechanical Engineering

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Development of Laboratory-scale Lamb Wave-based Health Monitoring System for Laminated Composites Leonardo Gunawan; Muhammad Hamzah Farrasamulya; Andi Kuswoyo; Tatacipta Dirgantara
Journal of Engineering and Technological Sciences Vol. 53 No. 4 (2021)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2021.53.4.7

Abstract

This paper presents the development process of a laboratory-scale Lamb wave-based structural health monitoring (SHM) system for laminated composite plates. Piezoelectric patches are used in pairs as actuator/sensor to evaluate the time of flight (TOF), i.e. the time difference between the transmitted/received signals of a damaged plate and those of a healthy plate. The damage detection scheme is enabled by means of evaluating the TOF from at least three actuator/receiver pairs. In this work, experiments were performed on two GFRP plates, one healthy and the other one with artificial delamination. Nine piezoelectric transducers were mounted on each plate and the detection of the delamination location was demonstrated, using 4 pairs and 20 pairs of actuators/sensors. The combinations of fewer and more actuators/sensor pairs both provided a damage location that was in good agreement with the artificial damage location. The developed SHM system using simple and affordable equipment is suitable for supporting fundamental studies on damage detection, such as the development of an algorithm for location detection using the optimum number of actuator/sensor pairs.
Experimental Work for Bar Straightness Effect Evaluation of Split Hopkinson Pressure Bar Afdhal Afdhal; Leonardo Gunawan; Tatacipta Dirgantara
Journal of Engineering and Technological Sciences Vol. 53 No. 6 (2021)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2021.53.6.13

Abstract

Bar straightness is one of several factors that can affect the quality of the strain wave signal in a Split Hopkinson Pressure Bar (SHPB). Recently, it was found that the bar components of the SHPB at the Lightweight Structures Laboratory displayed a deviation in straightness because of manufacturing limitations. An evaluation was needed to determine whether the strain wave signals produced from this SHPB are acceptable or not. A numerical model was developed to investigate this effect. In this paper, experimental work was performed to evaluate the quality of the signal in the SHPB and to validate the numerical model. Good agreement between the experimental results and the numerical results was obtained for the strain rates and stress-strain relationship for mild steel ST37 and aluminum 6061 specimen materials. The recommended bar straightness tolerance is proposed as 0.36 mm per 100 mm.
Karakterisasi Sifat Mekanik Mild Steel St37 dan High Strength Steel CR420LA pada Laju Regangan Menengah Leonardo Gunawan; Agustinus Dimas; Annisa Jusuf; Tatacipta Dirgantara; Ichsan Setya Putra
Mesin Vol. 25 No. 2 (2016)
Publisher : Mesin

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Abstract

Untuk mendapatkan prediksi respon yang cukup akurat dalam analisis tabrakan kendaraan darat, dimana terjadi pembebanan dan deformasi struktur dalam waktu yang cepat, diperlukan data sifat mekanik material pada berbagai laju regangan. Makalah ini menyajikan pengukuran sifat mekanik Mild Steel St37 dan High Strength Steel CR420LA pada kondisi kuasi-statik dengan laju regangan 0.001 s-1 dan pada kondisi dinamik dengan laju regangan 0.1 s-1, 1 s-1, 10 s-1, dan 100 s-1. Dalam pengujian, data beban terhadap waktu direkam menggunakan load cell, sedangkan data perpindahan terhadap waktu diperoleh menggunakan ekstensometer untuk uji kuasi-statik dan menggunakan kamera kecepatan tinggi diikuti dengan perhitungan regangan berdasarkan metode Korelasi Citra Digital (KCD) untuk kondisi dinamik. Hasil pengukuran menunjukan bahwa baja St37 dan CR420LA termasuk ke dalam jenis material yang sensitif terhadap laju regangan, dimana tegangan luluh material meningkat dengan naiknya laju regangan pada material.
The Influence of Sheet Metal Forming on The Axial Crushing Analysis of Top–Hat Columns Sigit P Santosa; Le Hoai Tam; Leonardo Gunawan; Annisa Jusuf
Mesin Vol. 25 No. 1 (2016)
Publisher : Mesin

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/MESIN.2016.25.1.4

Abstract

Reducing the rate of casualty in the crash events is always on the top priority of car manufacturers and customers. It is therefore necessary to make accurate predictions of car structural behavior during the crash events. To achieve this goal, the axial crushing behavior of the thin-walled top hat column needs to be understood thoroughly so that the crashworthiness performance of the column can be predicted accurately. The effect of sheet metal forming should be considered since many car crashworthiness components are fabricated by sheet metal forming. This paper presents a numerical study to investigate sheet metal forming effects such as: thickness distribution, residual stress and plastic strain change to the crushing force characteristics of the top-hat columns. First, the design of the top-hat column was generated by using deep drawing forming process simulation. Then, the forming parameters (geometry, residual stress, plastic strain, thickness distribution) were transferred to the non-linear finite element dynamic analysis model. The axial crushing simulations for the top-hat column with forming parameters were then performed and analyzed. The results showed that the sheet metal forming has a considerable effect on the crush behavior and performance of the thin-walled top-hat columns.
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

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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.
PENGARUH PERSONA MEREK TERHADAP EKUITAS MEREK DAN MINAT BELI KONSUMEN GENERASI Z DI RESTORAN DAN CAFÉ DI KOTA SURABAYA Leonardo Gunawan; Rizka Aula Assaf
Jurnal Ilmiah Manajemen, Ekonomi, & Akuntansi (MEA) Vol 8 No 2 (2024): Edisi Mei - Agustus 2024
Publisher : LPPM STIE Muhammadiah Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31955/mea.v8i2.4073

Abstract

Generasi Z memiliki peranan penting dalam konsumsi industri makanan dan minuman menimbang generasi ini akan menjadi potensi umur produktif yang besar di beberapa tahun yang akan mendatang dan potensial bagi bisnis. Namun, penelitian dengan topik brand personality, brand equity, dan buying intention belum popular dan diteliti secara spesifik dengan objek generasi Z. Padahal, secara teori generasi, mereka memiliki karakteristik yang berbeda dengan generasi pendahulunya. Maka dari itu, peneliti akan mengkaji pengaruh Brand Personality terhadap Brand Equity, dan Minat Beli Konsumen Generasi Z di Industri Food & Beverage Indonesia. Metode penelitian ini menggunakan metode kuantitatif multivariat dan menggunakan aplikasi SMART-PLS. Peneliti mengolah 98 data kuesioner utama dengan sampel konsumen Gen Z dengan rentang kelahiran 1997-2006 dan pernah membeli produk makanan dan minuman di restoran atau Café di Surabaya dalam rentang waktu setahun terakhir. Hasil penelitian mengungkapkan hasil yang positif dan signifikan antara Brand Personality terhadap Brand Equity, Brand Equity terhadap Purchase Intention, dan Brand Personality terhadap Purchase Intention.
Co-Authors Afdhal Afdhal Agustinus Dimas Andi Kuswoyo Annisa Jusuf Ichsan Setya Putra Le Hoai Tam Muhammad Hamzah Farrasamulya Nguyen Van Nhat Vu Rizka Aula Assaf Santosa, Sigit Puji Sigit P Santosa Tatacipta Dirgantara, Tatacipta