Surface roughness of ABS material on FDM process due to different orientation angle and layer thickness are investigated using an experimental method. The aim of this paper is to determine the effect of orientation angle and layer thickness on surface roughness on 3-dimension FDM printing on ABS material. A rectangle model with 60 mm length,10 mm in width, and 10 mm in height is used in this research. The orientation angle of model is 30, 45, and 60 degrees in layer thickness of 0.15 mm and 0.25 mm. The results indicates that the different orientation angle of the layer thickness causes the roughness value of the printed surface. The roughness surface value increases along with increasing of the orientation angle. The highest surface roughness value occurs at 60 degrees orientation angle in 0.15 mm layer thickness.
Laboratorium dikenal sebagai tempat dimana proses belajar mengajar dilakukan secara praktek menggunakan alat selain proses belajar teori di dalam kelas. Selain itu, kegiatan seperti pendataan alat dan peminjaman alat juga menjadi beberapa pekerjaan tambahan yang harus dilakukan oleh petugas laboratorium. Pekerjaan yang banyak, tentunya tidak dapat dilakukan seorang diri dan dengan cara yang manual seperti menggunakan catatan dalam buku. Penggunaan sistem aplikasi komputer dirasa dapat menjadi solusi dalam menangani berbagai macam pekerjaan yang ada agar dapat berjalan dengan lebih efektif dan efisien. Penelitian ini bertujuan untuk membantu pekerjaan dari petugas laboratorium teknik mesin dan beralih dari sistem manual menjadi sistem yang terkomputerisasi. Dari analisis yang dilakukan, penggunaan aplikasi memang dibutuhkan di dalam laboratorium produksi teknik mesin, demi mengurangi resiko daripada penggunaan buku manual. Sehingga dapat disimpulkan bahwa dengan dibuatnya sistem aplikasi komputer ini dapat menjadi jawaban atas permasalahan yang terjadi di dalam laboratorium teknik mesin UNJ dalam melakukan perawatan mesin.
Characteristics of void coalescence process due to hydrogen load effects in the multiple void array are simulated using the finite element method. The goals of this paper are to characterize the effects of hydrogen on the void coalescence process within the multiple void array, and to determine the void array and void volume fraction configuration in which hydrogen has the strongest effect on the occurrence of void coalescence. We use the couple analyses between the large deformation elastic-plastic analysis in the presence of hydrogen for structural analysis and hydrogen diffusion analysis using the hydrogen enhanced localized plasticity (HELP) theory. These coupled analyses are applied to the five different models with the different void volume fraction and void array. The numerical results show that both hydrogen and the void characteristics -void array and void volume fractionaffect metallic material failure. The internal necking void coalescence occurs in the square void array while the void sheet mode of coalescence occurs in the diagonal void array. Hydrogen has the strongest effect on the occurrence of void coalescence when the void volume fraction is large and the void array is square, induces a pronounced localized plastic deformation at the ligament between voids, and is present in high concentrations in regions with high values of the equivalent plastic strain.
In ductile fracture, the cup and cone fracture that occurs at the neck of a specimen is produced by the coalescence of internal voids which in turn grow by plastic deformation under the influence of a prevailing stress triaxiality. In this work, our concern is with regard to hydrogen embrittlement phenomena, where the presence of hydrogen influences the ductile fracture. We correlate the micro-scale void growth to the macro-scale deformation at the center part of the tensile test model of α-Iron to simulate the hydrogen effects on macro-and micro-scale model simultaneously. The tensile test model is used to determine the hydrogen effects at the macro-scale while the internal void model is used to determine the influence of hydrogen on the void growth. Loads in micro-scale are imported from the displacement results at the center part of the macro-scale tensile model. Our findings show that the proposed approach is feasible and can be implemented to correlate the micro-scale void growth to the macro-scale deformation at the center part of the tensile test model of α-Iron in the presence of hydrogen. Due to limitations of experimental data for hydrogen-material interaction, only α-Iron is considered in this study.
Permasalahan boundary value sering diselesaikan dengan metode numerik yang dibangun dengan basismatrik.Seiring berkembangnya kompleksitas produk, maka matrik yang disusun dalam menyelesaikan masalahboundary value juga semakin komplek.Salah satu teknik komputasi untuk menyelesaikan masalah boundary valueadalah dengan implementasi parallel komputasi. Makalah ini ditulis untuk mengimplementasikan proses parallelkomputasi, yang disebut dengan Domain Decomposition Method (DDM) pada metode elemen hingga (MEH) .Studiyang diambil adalah permasalahan linear elasticity sederhana berupa batang cantilever. Adventure, sebuah opensource software, digunakan untuk mengnalisis metode elemen hingga dengan DDM. Hasil analisis tersebut divalidasidengan perhitungan matematika dan analisis metode elemen hingga biasa (tanpa DDM) menggunakan MSCMarc.Hasil analisis menunjukkan bahwa analisis MEH dengan implementasi DDM meningkatkan ketelitian hasilanalisis dibandingkan dengan perhitungan MEH biasa.
This study aims to develop an assessment instrument in the subject area of expertise based on the Indonesian National Qualification Framework (KKNI). The development of tools includes the ability to work, mastery of knowledge, specialized skills and managerial skills of students at level 5 qualification level. The type of research used by Research and Development (R & D) with ADDIE (Analysis, Design, Development, Implementation, and Evaluation) models. Model validation had on conceptual models and hypothetical models. The results of limited trials obtained a score of 3.4 with the meaning below the model can be appropriately applied. The results of the field trial received a score of 3.38 which include in the excellent category, and the product was considered sufficient for use. This study tested the dimensions of knowledge and Special Skills.
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