Rolling Resistance Estimation for PCR Tyre Design Using the Finite Element Method

This study presents rolling resistance estimation in the design process of passenger car radial (PCR) tyre by using finite element method. The rolling resistance coefficient of tyres has been becoming one of main requirements within the regulation in many countries as it is related to the level of allowable exhaust gas emission generated by vehicle. Therefore, the tyre being designed must be digitally simulated using finite element method before the tyre is manufactured to provide a high confident level and avoid unnecessary cost related to failure physical product testing. The simulation firstly computes the deformation of several alternative designs of tyres under certain loading, and then the value of deformation force in each tyre component during deformation took place is calculated. The total force of deformation is considered as energy loss or hysteresis loss resulted in tyre rolling resistance. The experiment was carried out on three different tyre designs: two grooves, three grooves, and four grooves. The four groove tyre design gave the smallest rolling resistance coefficient (RRC). Finally, the simulation was continued to compare different crown radius of the tyres and the result shows that the largest crown radius generates the lowest rolling resistance

Optimalisasi Pemanfaatan Sekam Padi Menjadi Briket Arang Sekam untuk Menambah Pendapatan Petani di Desa Sukamaju, Jawa Barat

 Salah satu upaya untuk menambah pendapatan para petani adalah dengan mengolah limbah padi menjadi suatu produk yang memiliki nilai jual seperti arang sekam atau briket. Arang sekam memiliki banyak manfaat baik di dunia pertanian maupun untuk kebutuhan industri. Sekam padi dari hasil panen yang berlimpah, oleh sebagian petani biasanya dibakar untuk dijadikan pupuk, ada juga yang dijual langsung dengan harga yang sangat murah. Berdasarkan permasalahan tersebut, muncul ide untuk membuat alat-alat untuk memproses sekam padi menjadi produk yang bernilai jual lebih tinggi,  yaitu untuk pembakaran sekam menjadi arang sekam yang kemudian diolah lebih lanjut menjadi produk akhir berupa briket. Briket arang dapat dimanfaatkan untuk kebutuhan memasak, penerangan, maupun industri. Penelitian ini diawali dengan mengadakan pertemuan dengan komunitas petani di Desa Sukamaju, Kecamatan Tambelang, Kabupaten Bekasi untuk mengetahui kondisi dilapangan dan mengumpulkan data yang dibutuhkan. Proses berikutnya adalah merancang dan membuat alat pembuat arang sekam dan mesin pencetak arang sekam menjadi briket. Rancangan alat pembuat arang dilakukan untuk membuat arang dengan mempertimbangkan aliran udara saat pengarangan agar menghasilkan waktu yang lebih cepat dan mengurangi penyebaran asap, sedangkan pada perancangan mesin cetak briket arang dilakukan perhitungan kekuatan komponen mesin cetak yang diperlukan.  Setelah alat yang dibutuhkan selesai, dilakukan uji coba alat dan hasilnya memperlihatkan bahwa proses pembuatan arang membutuhkan waktu 20-30 menit untuk 10 kg sekam. Sedangkan hasil perhitungan komponen mesin cetak menunjukkan bahwa mesin cetak aman untuk digunakan. Hasil observasi menemukan bahwa saat ini sekam dihargai Rp 1000 per kg, dan arang sekam Rp 3000 sampai Rp 5000 per kg, sedangkan harga jual briket arang sekam bisa mencapai Rp 15.000 per kg. Dengan demikian, pengolahan sekam padi menjadi briket arang secara ekonomis akan lebih menguntungkan bagi para petani

Finite Element Analysis on ballistic impact performance of multi-layered bulletproof vest impacted by 9 mm bullet

Simulation is one of the most effective ways to reduce the cost and time needed to test the quality of a bulletproof vest. The widely applied method to predict the behavior of the materials is a macro-homogeneous model. However, even though it is low in computational cost, it has some accuracy issues. This work presents finite element analysis with both macro-homogeneous and meso-heterogeneous models to predict the behavior of the Kevlar composites during ballistic impact and qualitatively compares the simulation results with the experimental ones. The simulation reliability was ensured by numerical parameters such as the system energy balance and the limitation of artificial energy. The simulation results showed that the meso-heterogeneous yarn model successfully produced more detailed impact damage than the macro-homogenous model. In addition, the deformation of the Kevlar, the bullet, and the steel plate was close to the experiment results. The result was expected to be used as a consideration in determining the model type for another similar research

Finite Element Analysis on ballistic impact performance of multi-layered bulletproof vest impacted by 9 mm bullet

Simulation is one of the most effective ways to reduce the cost and time needed to test the quality of a bulletproof vest. The widely applied method to predict the behavior of the materials is a macro-homogeneous model. However, even though it is low in computational cost, it has some accuracy issues. This work presents finite element analysis with both macro-homogeneous and meso-heterogeneous models to predict the behavior of the Kevlar composites during ballistic impact and qualitatively compares the simulation results with the experimental ones. The simulation reliability was ensured by numerical parameters such as the system energy balance and the limitation of artificial energy. The simulation results showed that the meso-heterogeneous yarn model successfully produced more detailed impact damage than the macro-homogenous model. In addition, the deformation of the Kevlar, the bullet, and the steel plate was close to the experiment results. The result was expected to be used as a consideration in determining the model type for another similar research

PEMANFAATAN BIOSILIKA DARI SEKAM PADI SEBAGAI BAHAN PENGISI UNTUK TELAPAK BAN RAMAH LINGKUNGAN

Sekam padi merupakan limbah pertanian yang cukup melimpah dan saat ini belum dimanfaatkan secara optimal. Padahal, limbah sekam  padi mengandung silika  yang cukup banyak sekitar 90% dibandingkan dengan limbah biomassa lainnya. Oleh karena itu limbah sekam  padi dapat berpotensi untuk digunakan sebagai bahan pengisi yang bersifat menguatkan untuk industri ban. Penelitian ini bertujuan untuk membandingkan  sifat  pematangan  dan  sifat mekanik  dari  kompon  telapak  ban  ramah lingkungan  ya ng mengandung tiga jenis silika yang berbeda, antara lain, silika komersial dari pasir silika, silika dari sekam padi yang diekstraksi di laboratoratorium dan biosilika komersial. Pencampuran silika dengan karet dilakukan di dalam internal mixer untuk memfasilitasi reaksi silanisasi. Hasil menunjukkan semakin tinggi BET surface area dan adanya silanol grup di permukaan silika dapat meningkatkan sifat pematangan dan sifat mekanik telapak ban ramah lingkungan

Produksi Pelindung Wajah (Face Shield) Dengan Metoda Cetak 3D untuk Tenaga Medis di Puskesmas dan Rumah Sakit Di Awal Pandemi Covid-19 di Indonesia

Kelangkaan alat pelindung diri (APD) bagi tenaga medis di sejumlah puskesmas (pusat kesehatan masyarakat) dan rumah sakit pada awal pandemi Covid-19 sejak bulan Maret tahun 2020 telah meyebabkan berbagai elemen masyarakat bahu membahu untuk mengatasi kelangkaan APD tersebut. Mahasiswa dan dosen Universitas President telah mengambil inisiatif membuat face shield untuk dibagikan kepada para tenaga medis di berbagai puskesmas dan rumah sakit di seluruh Indonesia. Pembuatan face shield tersebut menggunakan metoda 3D printing untuk mempercepat proses pembuatannya. Dalam kurun waktu Maret sampai Juni 2020 telah dikirimkan 1500 face shield ke 57 puskesmas dan rumah sakit di seluruh Indonesi

Aplikasi Android menggunakan Location Based Service (LBS) untuk Navigasi Tujuan Wisata di Kabupaten Garut

Garut Regency is a Regency in West Java Province, Indonesia. The capital is Tarogong Kidul. The regency is adjacent to Sumedang regency in the north, Tasikmalaya regency in the east, Indian Ocean in the south, and Cianjur and Bandung regencies. The number of tourists who travel in Garut regency, making the workers in the tourism office burdened with the many questions surrounding the location thrown by local and foreign tourists. With Location Based Service technology, tourists can find the location of the desired tourist position without a guide from the tour guide though. In this study the authors use research methods Development Life Circle Software (SDLC) waterfall (Waterfall), while for application method using Location Based Service (LBS). This application utilizes Global Positioning System (GPS) that has been integrated with the handset. With the LBS application is expected to provide accurate information, clear and precise to know the points of location Nature Tourism, and can facilitate local and foreign tourists and the community, especially Garut regency

Utilization of biosilica for energy-saving tire compounds: Enhancing performance and efficiency

Energy-saving tires have been developed by researchers in the industry in order to minimize hysteresis loss. In general, this is achieved by combining precipitated silica sourced from silica sand with a silane coupling agent. This strategic reaction serves to elevate the performance characteristics of tread tire, effectively enhancing their properties. Therefore, this research is aimed to investigate the utilization of commercially available biosilica compared to high dispersed (HD) silica, examining their potential as reinforcing agents in the composition of passenger tread tire compound. This compound was formulated using a blend of solution styrene-butadiene rubber (SSBR) and butadiene rubber (BR). A comprehensive analysis was conducted to assess the impact of varying ratios between biosilica and HD silica on the mechanical and dynamic properties of tread tire compound composed of SSBR and BR blend. The results showed that the incorporation of biosilica could effectively reduce the filler network resulting in better dispersion of biosilica in the SSBR/BR blend matrix. As a result, it improved wet grip (44%) and rolling resistance (26%) while maintaining abrasion resistance compared with HD silica in passenger tread tire compound. The application of biosilica as an eco-friendly reinforcement material exhibited its potential for elevating the performance of energy-efficient tread tire