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"This book presents experimental results and theoretical advances in the field of ultra-low-cycle fatigue failure of metal structures under strong earthquakes, where the dominant failure mechanism is ductile fracture. Studies on ultra-low-cycle fatigue failure of metal materials and structures have caught the interest of engineers and researchers from various disciplines, such as material, civil and mechanical engineering. Pursuing a holistic approach, the book establishes a fundamental framework for this topic, while also highlighting the importance of theoretical analysis and experimental results in the fracture evaluation of metal structures under seismic loading. Accordingly, it offers a valuable resource for undergraduate and graduate students interested in ultra-low-cycle fatigue, researchers investigating steel and aluminum structures, and structural engineers working on applications related to cyclic large plastic loading conditions."

"Metoda Elemen hingga adalah salah satu metoda numerik yang dipakai untuk menyelesaikan persamaan differensial. Pada tugas akhir ini akan dibahas penggunaan Metoda Elemen Hingga dalam menyelesaikan masalah aliran fluida viskous inkompresibel dimana persamaan atur dari fluida ini adalah persamaan yang multivariabel."

"The finite element method for fluid dynamics offers a complete introduction the application of the finite element method to fluid mechanics. The book begins with a useful summary of all relevant partial differential equations before moving on to discuss convection stabilization procedures, steady and transient state equations, and numerical solution of fluid dynamic equations.The character-based split (CBS) scheme is introduced and discussed in detail, followed by thorough coverage of incompressible and compressible fluid dynamics, flow through porous media, shallow water flow, and the numerical treatment of long and short waves. Updated throughout, this new edition includes new chapters on:- Fluid-structure interaction, including discussion of one-dimensional and multidimensional problems.- Biofluid dynamics, covering flow throughout the human arterial system.Focusing on the core knowledge, mathematical and analytical tools needed for successful computational fluid dynamics (CFD), "

"Pada tahun 2019, terjadi keruntuhan lereng di Lawe Sikap, Kutacane, Nanggroe Aceh Darussalam (Erly Bahsan S.T, 2020). Berdasarkan pengamatan pola keruntuhan, diperkirakan bahwa keruntuhan lereng dikategorikan sebagai keruntuhan guling atau toppling failure (Erly Bahsan S.T, 2020). Berdasarkan kasus tersebut, diperlukan suatu analisis stabilitas lereng untuk menggambarkan perkiraan pola keruntuhan, mencari nilai faktor keamanan lereng, serta faktor apa saja yang menjadi penyebab keruntuhan tersebut. Salah satu metode dalam melakukan analisis stabilitas lereng adalah dengan metode elemen hingga atau finite element method (FEM). Menurut penelitian, ditemukan bahwa FEM lebih unggul dalam melakukan analisis stabilitas lereng dibandingkan dengan limit equilibrium method (LEM) atau metode keseimbangan batas. Pada penelitian ini, penulis menggunakan software MIDAS GTS NX yang merupakan salah satu software untuk melakukan analisis stabilitas lereng yang berbasis FEM. Dalam melakukan analisis stabilitas lereng dengan keruntuhan guling, diperlukan model geometri lereng serta diskontinuitas atau celah antar batuan utuh yang sesuai dengan kondisi eksisting. Selain itu, pemilihan model konstitutif juga berpengaruh terhadap hasil analisis yang dilakukan. Model geometri yang dipilih adalah dengan membuat celah elemen antara batuan utuh (intact rock) dengan sudut kemiringan sebesar 60° searah dengan arah jarum jam. Dalam analisis ini, penulis menggunakan model konstitutif generalized hoek-brown yang dinilai cocok digunakan untuk menganalisis stabilitas lereng batuan. Terdapat beberapa faktor yang berpengaruh terhadap kestabilan lereng batuan, yaitu adanya pemotongan lereng akibat proses konstruksi dan adanya pengaruh dari muka air tanah. Selain itu, MIDAS GTS NX juga terbukti mampu dalam memodelkan keruntuhan guling pada lereng objek studi.

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In 2019, there was a slope collapse in Lawe Sikap, Kutacane, Nanggroe Aceh Darussalam (Erly Bahsan S.T, 2020). Based on the observation of the failure pattern, it is estimated that slope failure is categorized as a toppling failure (Erly Bahsan S.T, 2020). Based on this case, a slope stability analysis is needed to describe the estimated failure pattern, find the value of the slope safety factor, and what factors cause the collapse. One of the methods for analyzing slope stability is the finite element method (FEM). According to the study, it was found that FEM is superior in performing slope stability analysis compared to the limit equilibrium method (LEM) or the boundary equilibrium method. In this study, the author uses the MIDAS GTS NX software which is one of the software to perform slope stability analysis based on FEM. In conducting slope stability analysis with toppling failure, a slope geometry model and discontinuity or gap between intact rock are required according to existing conditions. In addition, the selection of a constitutive model also affects the results of the analysis carried out. The geometric model chosen is to create an element gap between intact rock (intact rock) with a slope angle of 60° in a clockwise direction. In this analysis, the author uses a generalized Hoek-brown constitutive model which is considered suitable for analyzing rock slope stability. There are several factors that affect the stability of rock slopes, namely the existence of slope cutting due to the construction process and the influence of the groundwater level. In addition, MIDAS GTS NX is also proven to be able to model the toppling failure on the slopes of the study object."

"Eksperimen pengelasan dan analisis termal dengan menggunakan Finite Element Method dilakukan pada material baja AH36 dengan membandingkan antara proses pengelasan Flux Cored Arc Welding dan Gas Metal Arc Welding. Tujuan dari penelitian ini adalah untuk membandingkan sifat mekanis dan struktur mikro lasan FCAW dan GMAW dari baja HSS AH36 dan analisis termal menggunakan simulasi FEM dengan perangkat lunak ANSYS. Penentuan kekuatan mekanik dari hasil pengelasan AH36 dilakukan dengan menggunakan microhardness Vickers dan Charpy V-notch impact tester. Scanning Electron Microscopy dan mikroskop optik menjadi alat yang digunakan untuk mengevaluasi evolusi struktur mikro di daerah zona fusi, zona yang terkena dampak panas dan logam dasar. Nilai distorsi yang diukur sangat kecil yang sesuai dengan pengamatan aktual pada hasil lasan yang tidak terjadi distorsi. Kontur dari panas akibat pemanasan dapat terlihat dari sumber panas yang menyebar ke semua arah. Nilai kekerasan yang terukur pada logam induk lebih kecil dibandingkan pada area terkena panas (HAZ) kemudian nilai kekerasannya turun pada daerah lasan. Nilai ketangguhan pada proses GMAW lebih tinggi dari proses FCAW karena kandungan nikel yang terdapat pada kawat las.

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Welding and thermal analysis experiments using Finite Element Method were carried out on AH36 steel by comparing between the welding process of Flux Cored Arc Welding and Gas Metal Arc Welding. The purpose of this study was to compare the mechanical properties and microstructure of FCAW and GMAW welds from AH36 HSS steel and thermal analysis using FEM simulation with ANSYS software. Determination of mechanical strength from welding results was done using the Vickers microhardness and Charpy V-notch impact tester. Scanning Electron Microscopy and optical microscopy are tools used to evaluate microstructure in the fusion zone, a zone that discusses heat evolution and base metals. Small distortion value according to the actual results of the weld results that no distortion has been detected. Contour of heat that occurred can be seen from the heat source that spreads in all directions. The hardness values measured on the base metal are smaller than those in the heat approved area (HAZ) then the value of in the weld area. The toughness value in the GMAW process is higher than that of the FCAW process because of the nickel content needed in welding wire."

"Traditionally, engineers have used laboratory testing to investigate the behavior of metal structures and systems. These numerical models must be carefully developed, calibrated and validated against the available physical test results. They are commonly complex and very expensive. From concept to assembly, Finite element analysis and design of metal structures provides civil and structural engineers with the concepts and procedures needed to build accurate numerical models without using expensive laboratory testing methods. "

"ABSTRAKFatigue strength merupakan poin penting yang perlu diperhatikan dalam dunia keteknikan. Fatigue strength dipengaruhi oleh korosi, kekasaran permukaan, dsb. Terdapat beberapa metode yang bisa digunakan untuk meningkatkan fatigue strength, salah satunya yakni dengan surface treatment seperti heat treatment, ultrasonic impact treatment, Galvanisasi dsb. Dalam studi ini, simulasi untuk memprediksi fatigue life terhadap galvanized and non-galvanized S45C dengan menggunakan metode elemen hingga (commercial software) telah dilakukan untuk mengetahui besar pengaruh dari galvanized material dan non-galvanized spesimen. Hasil dari simulasi didapatkan bahwa nilai fatigue strength dari non-galvanized spesimen adalah sekitar 95% dibandingkan dengan data dari eksperimen. Lalu simulasi dilanjutkan untuk galvanized spesimen. Fatigue strength dari galvanized specimen sekitar 25% lebih tinggi dari non-galvanized spesimen. Sehingga bisa disimpulkan bahwa software bisa digunakan untuk memprediksi fatigue strength.

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ABSTRACT

Fatigue strength is an important point that needs to be considered in the world of engineering. Fatigue strength is affected by corrosion, surface roughness, etc. There are several methods that can be used to increase fatigue strength, one of them is surface treatments such as heat treatment, ultrasonic impact treatment, Galvanization, etc. In this study, a simulation to predict the fatigue life of galvanized and non-galvanized S45C by using the finite element method (commercial software) has been carried out to determine the effect of galvanized material and non-galvanized specimens. The results of the simulation show that the fatigue strength value of non-galvanized specimens is about 95% compared to the data from the experiments. Then the simulation is continued for the galvanized specimen. Fatigue strength of galvanized specimens is about 25% higher than non-galvanized specimens. So it can be concluded that software can be used to predict fatigue strength."

"This book addresses the static and dynamic analysis of linear elastic size-dependent structures based on the modified couple stress theory. It focuses on establishing the governing equations of the size-dependent structures, deriving the associated finite element models, and implementing those models using the R programming language. The implemented functions are employed to develop a special R package (equivalent to a MATLAB toolbox) called microfiniteR for this book.

In each chapter, the governing equations are formulated using the variational method, and the behaviour of the structures is examined on the basis of their load-deformation characteristics (in the case of static analyses) and by evaluating their eigenvalues (in the case of dynamics and buckling problems). The first chapter introduces readers to the R programming language, beginning with the resources needed to make use of the language and ending with a list of recommended texts. The remaining chapters cover the requisite linear elastic theory and highlight the implemented R functions. Each chapter concludes with a brief summary and relevant references. "

"ABSTRAK

Fatigue Design Analysis pada Struktur Kapal merupakan hal yang cukup baru di dunia Enjiniring Perkapalan. Struktur Kapal yang sangat rumit dan sangat detail membutuhkan ketelitian yang tinggi untuk menghitung kekuatan strukturnya, lebih-lebih menghitung bagian per bagian strukturnya. Dengan menggunakan metode Finite Element penghitungan umur kelelahan kapal dapat dilakukan dengan lebih mudah, cepat dan akurat. Di samping itu, tidak hanya mencari nilai umur kelelahan kapal akan tetapi Finite Element dapat melakukan analisa frekuensi natural dari struktur, respon harmonik dari beban harmonik sinusoidal dan getaran acak dari beban yang acak.

Faktor utama yang mempengaruhi umur kelelahan kapal dibagi menjadi 3 kategori besar, yaitu beban statik, beban dinamik dan tekanan hidrostatik. Beban statik berasal dari muatan kapal, beban dinamik berasal dari gelombang laut, tekanan hidrostatik berasal dari kedalaman laut. Penghitungan beban dinamik dilakukan dengan menggunakan simplifikasi dan distribusi normal. Umur kelelahan kapal didapat sebesar 49 tahun dengan equivalent alternating stress von-misses terbesar terdapat pada Plate 5 mm sebesar 31,23 Mpa. Umur kelelahan kapal didapat dari bagian yang mengalami tegangan terbesar ketiga. Hal ini disebabkan oleh faktor material, bentuk, luas, permukaan dan produksi material. Frekuensi yang harus dihindari kapal ketika beroperasi adalah 50-90 Hz.

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ABSTRACT

Fatigue Design Analysis on ship‟s structure is relatively new in Marine engineering. The ship structures is so complicated and details, that makes analyzing ship structures is so hard and take so much time. Using Finite Element for Fatigue Design Analysis makes the analysis easier, faster and more accurate. Beside that, not only doing the Fatigue Design Analysis but Finite element also can analyze the harmonic response of the structure from sinusoidal load and random vibration from random load.

The main factor affecting the life of a ship divided by three catgeories, Static Load, Dynamic Load and Hidrostatic Pressure. Static load caused by cargo load, dynamic load caused by sea wave and hidrostatic pressure caused by the depth of the sea. Dynamic load calculated using simplification and Gaussian distribution. The final result of the ship‟s life is 49 years with the biggest equivalent alternating stress von-misses in Plate 5 mm and the amount of equivalent alternating stress von-misses is 31,23 Mpa. Frequency that the ships must be avoided when the ship is in operation is 50-90 Hz.

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