Papers by Keyword: Stress Analysis

Abstract: Offshore pipelines are crucial for transporting fluids from offshore platforms to onshore processing facilities. However, these pipelines are susceptible to damage from third-party activities, such as collisions with ship anchors. An inspection revealed a dent in the pipeline with a depth of 111 mm, resulting in a dent depth to outside diameter ratio of 31.21%. According to various regulatory codes, this ratio indicates failure. Despite this, no leaks or ruptures were observed during the inspection. To assess the pipeline's integrity, finite element analysis (FEA) using Abaqus was conducted to determine the maximum stress in the dented area. The analysis produced a graph illustrating the relationship between stress and the allowable operating pressure of the pipeline.

Abstract: The widespread use of aging materials in engineering, along with the growing demands for reliability and cost-effective design, poses new challenges for researchers in improving mathematical tools, methods for describing experimental data, and developing both exact and approximate solution techniques for specific problems. This paper investigates the stress distribution in a viscoelastic rotating disk of variable thickness mounted on a rigid shaft. An approximate method is proposed for solving the governing differential equation with variable coefficients, based on the use of canonical polynomials and the τ-method of Lanczos. The resulting polynomials obtained using this approach approximate the desired solution approximately 2n times more accurately than hypergeometric functions. The generalization to the viscoelastic case is achieved by applying the Volterra principle. A numerical example is provided. The scientific novelty lies in the application of canonical polynomials and the τ-method instead of hypergeometric functions to solve the stress analysis problem of a rotating viscoelastic disk with variable thickness. The canonical polynomials – either in general form or numerically determined using the relationships derived in this study – can also be constructed for other similar problems.

Abstract: In this study, effort was made to develop novel, cutting-edge composite materials consisting of conducting Al-CNTs and green synthesis silver nanoparticles (AgNPs). Spark plasma sintering (SPS) and very intense ball milling were used to develop the composites. The nanocomposites' microstructure, thermal and electrical conductivity were determined. Al-4%CNTs was refined into finer grains when AgNPs are present. The Al-4%CNTs+2%Ag.NPs composite produces a higher dislocation density because of the production of sub-grain. Al-AgNPs + CNTs can be used to make conductors with a high aspect ratio and lower contact resistance at the CNT junctions. It was established that enhanced electrical and thermal conductivity can be obtained using the developed AgNPs from sustainable materials to increase the dispersion of CNTs in Al for the production of high tensile conductors.

Abstract: The increase in the use of electricity in Indonesia is also due to the industrial sectors which have enlarged their area and the use of electricity to develop their business. Indonesia is a developing country which is still in the stage of development and development so that it can become a developed country. This research is main to develop rainwater based power plant turbine and anaysis the stress analysis and test the rig. Simulation of stress analysis in the design of a water turbine, there is 1 force that is applied, namely the force in the area where the gallon water container with a volume of 15 liters is placed. The force exerted is 147.1 N which is obtained from calculating the mass of a gallon filled with 15-liters of water multiplied by the acting gravitational force. The results of the stress analysis simulation show a visualization image consisting of von mises stress, displacement, and the safety factor displays blue for all parts of the water turbine frame design which states that the amount of force exerted is still relatively safe. Water discharge is taken using a digital water sensor that can detect the water flow rate accurately. Water power of this system is 1.14 Watt. The water pressure generated by the fluid mechanical energy working in the water turbine is directly proportional to the resulting blade of turbine rotation. The voltage comparison resulting from the number of blade design states that the most optimal design is in the number of 8 blades, which has the greatest voltage value of 910.1 V at the 181 rpm. Hence, the number of 8 blades is the most effective turbine design for rotating the generator.

Abstract: An important role a landing gear plays is that it aids in the landing and takeoff of aircraft. The landing gear must be designed in such a way that it can take these stresses in static and dynamic situations. This is to accommodate both rough and smooth landings that result from various loads acting upon it, such as drag force, vertical load, and side load. In the aviation industry, landing gear stress is a key concern, and different research in this field has previously yielded excellent results. However, the time has come to raise the bar even higher. This report will focus on the optimization of the Boeing 777's nose landing gear to better withstand rough landings. During the timeframe of this research, SOLIDWORKS was utilized to model and analyze various components of the landing gear. The results summarize that a single material should be avoided throughout the components of the landing gear. Components such as pistons with a larger stress allocation should be made of titanium alloy, while components with a lesser stress allocation should be made from aluminum alloy.Abstract. An important role a landing gear plays is that it aids in the landing and takeoff of aircraft. The landing gear must be designed in such a way that it can take these stresses in static and dynamic situations. This is to accommodate both rough and smooth landings that result from various loads acting upon it, such as drag force, vertical load, and side load. In the aviation industry, landing gear stress is a key concern, and different research in this field has previously yielded excellent results. However, the time has come to raise the bar even higher. This article will focus on the improvement of the Boeing 777's nose landing gear to better withstand rough landings. During the timeframe of this research, motion study in SOLIDWORKS 2020 (Stand-alone license) was utilized to model and analyze various components of the landing gear. The results summarize that a single material should be avoided throughout the components of the landing gear. Components such as pistons with a larger stress allocation should be made of titanium alloy, while components with a lesser stress allocation should be made from aluminum alloy.

Abstract: Fan-out wafer-level package is a very promising packaging technology with good thermal and electrical performance. The fan-out wafer-level package exhibits beneficial features such as low profile, high I/O density, low cost, and efficient computing. The package experiences large temperature variations in the assembly phase which causes internal stresses. In particular, the mismatch between the coefficient of thermal expansion of the epoxy molding compound and the substrate due to the cool down phase of the cure process causes the internal stresses in the package. These internally induced stresses result to interfacial delamination. In this study, the interfacial delamination on a fan-out wafer-level package right after post mold cure of glass wafer was evaluated using the stress-based damage index through the finite element analysis in the ANSYS software package. The model was validated by comparing the simulation result of the glass wafer warpage to the existing experimental result from literature. From the warpage simulation of the glass wafer, the region on the package with high stress level was located and examined which may cause interfacial delamination. The maximum shear stress and principal stress at the epoxy molding compound and the Silicon chip interface was found to exceed the adhesion strength. This indicates that the interfacial delamination is inevitable. The information obtained from the stress analysis of molded wafer provides insight for the possible interfacial failure of fan-out wafer-level package in the individual package when subjected to thermomechanical loads.

Abstract: According to the ICF (International Classification of Functioning, Disability, and Health), a prosthetic is a device used to restore or replace the function of a missing limb as a result of a rare genetic defect, dangerous incident, surgical trauma, or disease that limits the amputee's ability to participate in daily life. Prosthetic limb sockets were formerly made out of a wide variety of materials before the development of thermoplastics and composites. Plant fibers are favored due to their low density. Both their strength and rigidity are remarkably high considering their low weight and inexpensiveness. Plant fiber is one of the most popular ways to give polymer composites more strength because of its low production costs and stretchability. Following a brief introduction to the many types of natural fibers (both plant and animal), this article provides a comprehensive assessment of the literature from the past decade that focuses on the mechanical characteristics of plant materials. Reinforced polymers are made with fibers. This literature study will focus on the mechanical properties and behavior of plant fibers used to create sockets for prosthetic limbs. If an article is written about the overall features of composites made with fibers made from the plant, it is expected to be of great use to the research community in the field of composites.

Abstract: The aim of this work is a development and characterization of a sustainable product from solid waste from civil construction. Morphology of collected waste has been analyzed by SEM/EDS. Residues have been macerated, mixed in different proportions with cement and water, and made into rectangular boxes. Mechanical test has been carried out by flexing three points on specimens, absorbing water and analyzing fracture by SEM. Morphology of samples have shown a heterogeneous and porous mass, with particles of different sizes, few agglomerates, and presence of organic material. Resistance to average rupture of samples has been obtained in MPa, characteristic of concrete for structural application. For CDR to be used in sustainable ceramics, it is recommended to improve a process of comminution and homogenization to guarantee reproducibility of lots and technological product properties. This being so, a mockup has been developed proposing a hollow element type product, Cobogó style, indicating potential of using civil construction waste as a sustainable product.

Abstract: The cracked blade in L-0, L-1 governor side, and L-1 generator side were found when A 220 MW low-pressure steam turbine was checked in the serious inspection. However, the crack population more dominant at L-1 Gen compared to L-0 Gov and L-1 Gov. Most of the cracks were located on 300-400 mm from the root of the blade span, and it did not associate with the pitting defect. In this study, the root cause of L-1 blade failure was investigated. There is three-stage of analyzing process, firstly capturing the airfoil and dimension of L-1—secondly, the material properties analysis, and finally stress analysis of L-1 by the finite element analysis software. L-1 is the blade with the chord length on the tip L-1 blade longer than root as 2.1% and the angle of an airfoil from root to tip twisted as 24 degrees. The type of material did not look precisely similar to AISI 422 because its hardness-strength is lower than AISI 422 as 5.1%. The finite element analysis shows that there was a symptom of the imprecise shroud gap that promoted maximum stress at 300-400 mm from the root area of the L-1 blade span. Moreover, a lack of hardness-strength material cannot accommodate the excessive movement of the blade and promoted the initial crack of L-1. A crack length blade as 16 mm shows a lower number of cyclic (N_f) to failure tremendously compared to standard blades such as 32,367 of the number cyclic for regular blade and 42.6 for the crack blade. Increasing 2 mm of initial crack will decrease significantly the number of cyclic N_f of the blade. It was tearing mode crack propagation of L-1 results a significant stress intensity factor compared to other modes, especially at 16 mm length of the crack.

Abstract: Electronic products have been following light, thin, short, small as goals. In recent years, not only do these features have to provide more functionality and reliability. In response to this demand, many new processes such as wafer-level 7 nm euv and electronic packaging solutions have been developed in the market. Stacked wafer technology has been widely used in electronic packaging solutions in a variety of storage devices and electronic products. The accompanying problems and challenges continue to emerge, in which the delamination of the package failure mode leads to the inability of electronic products to operate as the biggest issue. This study is mainly to investigate the thermal stress behavior of the vertical stacking of chip bonds of wafer adhesives to reduce the thickness of the wafer in the stacked wafer structure to Improve package reliability by reducing the amount of deformation Utilize one-half symmetry model and adopt the reflow profile of JESD22-a113 (25 °C ~ 260 °C) As a basis and import into the ansys software for parametric development, Then use the Taguchi experiment method to configure the experimental parameters to explore the optimization parameters. Finally, the experimental results and the delamination results were verified by the Taguchi experiment method, and the stress shrinkage gradient model was introduced to find the next best potential factor for reducing the maximum stress, such as binder material Tg and Young's modulus compensation thermal expansion system. Observe the thermal stress behavior of stacked chips and help provide a reference for providing modified changes during development.