Development Of Crack Propagatio Part Two: At The Crack Region Of A Plate

ABSTRACT A method is developed for the detection of the crack propagation in a plate with single edge crack. It extends previous work The plate was subjected to various combinations of stress levels (SL) and stress ratios (R). Two accelerometers were used to measure the longitudinal displacement amplitude at the plate\u27s crack region. Data acquisition was done by measuring the longitudinal displacement amplitude at specific crack length, as well as by counting the cycles. The accuracy of the results is further assessed by comparison with results from the previous work. It is shown that the present work can yield very accurate results. In order to validate the method used in the present study, the results of this method is compared with results of numerical finite element calculations, and the agreement is quite satisfactory. Keywords: longitudinal displacement, finite element, crack propagation, plate, accelerometer

FUNDAMENTA LS OF BIOMECHANIC BIOMEDICAL ENGINERING

Studi tentang biomechanics telah berkembang pesat dari awalnya hanya aplikasi studi mekanika teknik yang sederhana kemudian meluas dengan pelibatan berbagai bidang studi. Dalam bidang biomechanics buku ini sangat membantu mahasiswa ataupun peneliti untuk memahami dasar-dasar mekanika dan dinamika tubuh manusia, yang menjadi bidang kajian penting dalam studi rekayasa biomedik. Buku ini memberikan pengetahuan yang memadai tentang konsep statika, gerak, dinamika, pemodelan, dan aplikasinya dikaitkan dengan bagian-bagian tubuh dan gerakan manusia, hal-hal yang sangat penting yang seharusnya diketahui dalam pengembangan biomechanics, tetapi sebelumnya sangat jarang untuk didapatkan pustakanya

Strut Linker Geometry Improving Mechanical Behaviorof Coronary Stent

Stent is one of the common solution that is offered to the patient with atherosclerosis. An ideal stent should have good mechanical and biological properties. This research aims to analyze how importance strut linker geometry affect mechanical behavior of stent especially on recoil percentage, foreshortening percentage and fatigue safety factor prediction using finite element analysis. The result showed that strut linker geometry would specify the mechanical behavio

SIMULASI FINITE ELEMENT PENGARUH SIDE CRACK TERHADAP KARAKTRISTIK GETARAN PLAT ALUMUNIUM

The use of plates in engineering is usually found as the structure of the building, and aircraft wings. In operation, the plate often fail to crack. Crack causes sudden failure that can harm humans who are around the structure. Therefore, cracks in the structure must be detected as early as possible. One way to detect the crack was to detect changes in the characteristics of vibration that was natural frequencies and mode shapes of structure. The purpose of this study was to determine the effect of position and crack length on natural frequency and shape mode that can be used to detect crack. In this study, finite element method was using to analysis the natural frequencies and mode shapes of aluminum plate. The geometry of plates was made using Abaqus / CAE 6.11. the side crack made as notch 0.25mm width and boundary conditions was the clamp-free-free-free (CFFF). This research shown that the longer crack the smaller natural frequency of plate.Penggunaan plat dalam bidang teknik sangat banyak ditemukan seperti struktur bangunan, dan sayap pesawat terbang. Dalam operasionalnya, plat sering mengalami kegagalan crack. Crack dapat menyebabkan kegagalan tiba-tiba yang dapat membahayakan manusia yang berada di sekitar struktur tersebut. Oleh karena itu, crack pada suatu struktur harus dideteksi sedini mungkin. Salah satu cara mendeteksi crack adalah dengan mendeteksi perubahan karakteristik getaran yaitu frekuensi alami dan mode shape suatu strukstur. Tujuan penelitian ini adalah untuk mengetahui pengaruh posisi dan panjang crack terhadap frekuensi alami dan mode shape yang dapat digunakan untuk mendeteksi crack. Pada penelitian ini, analisis frekuensi alami dan mode shape plat alumunium 1100 dilakukan dengan simulasi finite element menggunakan software ABAQUS/CAE 6.11. Penelitian dilakukan dengan membuat geometri plat di ABAQUS/CAE 6.11 dan side crack berupa notch dengan lebar 0.25mm dan boundary condition clamp-free-free-free (CFFF). Dari penelitian ini diperoleh bahwa semakin panjang crack maka frekuensi alami plat semakin kecil

Penelitian Sifat-Sifat Akustik Dari Bahan Kertas Dan Plastik Sebagai Penghalang Kebisingan

ABSTRAK The goal of this research is to determine acoustic properties of alternative materials used to replace plants as noise barrier. The materials investigated are paper and plastic because these materials can also he used inside a room or as room partition. The flow resistivity of materials are measured, and then used as a room partition in a semi anechoic room. A sound source was then tuned and the Sound Pressure Level (SPL) in both sides of room is measured. The SPL difference between two rooms indicates the Noise Reduction (NR). The investigations were done using different value of flow resistivity and frequency. The results show that NR is increasing as the flow resistivity and frequency increased. For flow resistivity of 800 MKS Rayls/m, the paper can attenuate noise up to 20 dB at frequency 8000 Hz. This value is much higher then the value achieved using plants. For both papers and plastic, in the frequency range 200 â 2500 Hz there is a fluctuation value of NR due to the behaviour and properties of materials. This region is called a coincidence region. Key words : Noise, Flow Resistivity, Noise Reduction, Sound Pressure Leve

Perancangan Bejana Tekan Vertikal Berbasis Code ASME VIII Divisi 1 (Studi Kasus Separator Unit Karaha PT. Pertamina Geothermal Energy)

Paper ini membahas perancangan bejana tekan vertikal berbasis code ASME VIII divisi 1 dengan studi kasus separator di Fluid Collection and Reinjection System (FCRS), unit Karaha PT. Pertamina Geothermal Energy. FCRS digunakan untuk mengumpulkan dan mengirimkan uap ke pembangkit listrik geothermal 1x30 MW. Separator berfungsi untuk memisahkan uap dan brine dari sumur produksi. Perancangan bejana tekan meliputi pressurized dan non pressurized part. Pressurized part terdiri dari shell, head dan nozzle dengan pertimbangan tekanan dan temperatur kerja. Non pressurized part terdiri dari support, lifting lug, tailing lug dan peralatan pendukung lainnya. Dari hasil perancangan didapatkan tebal shell dan head adalah 20 mm dengan diameter 1700 mm. Tegangan yang terjadi pada analisa perhitungan tegangan saat operasi kurang dari tegangan maksimal yang diijinkan pada material pada temperatur operasi sehingga shell dan head aman.Ukuran nozzle yang dipakai adalah untuk inlet dan steam outlet 20” schedule 40, dan untuk brine outlet 4” schedule 160. Jenis flange untuk semua nozzle adalah RFWN dengan rating 300 lb dengan konstruksi reinforcement pad di semua nozzlenya. Dari hasil analisa kekuatan nozzle dan reinforcement pad disimpulkan bahwa desain mampu menahan beban operasi. Peralatan pendukung yang terdiri skirt, anchor bolt dan basering dirancang mampu menahan beban berat, dan beban dinamis gempa dan angin. Dari tinjauan konstruksinya, bejana tekan ini cukup aman karena mempunyai tegangan kerja di bawah tegangan yang diijinkan. Kata kunci: Bejana tekan,ASME VIII divisi I, separator, geotherma