Mechanical strength of highly preloaded bolts affected by the ovalization of an aircraft wheel

This work presented in this paper concerns the modeling of the tensile and bending behavior of bolts in an airplane wheel. The design of a very rigid airplane tire means that the airplane wheel must be separated into two parts. In order not to have a separation between the two parts, several bolts with high preload are used. The main objective of this work is to predict the mechanical behavior of this assembly in a preliminary design phase with geometrical and global mechanical data. To achieve this objective, a simplified semi-numerical 1D model is developed. The complex geometry of the wheels is modeled by axisymmetric elements, while beam elements define the geometries and mechanical behavior of the bolts. The model is improved in non-axisymmetric cases to include the ring effect due to the wheel ovalization. Different cases are simulated (inflation and rolling). For each load case, the most stressed fastener is examined. Then, a comparison between its static and fatigue stress results and those of the 3D finite element reference model considered is analyzed for the validation of the developed tool. The semi-numerical model is used in the preliminary design phase and permits the geometric and mechanical properties of the aircraft wheel and fasteners to be defined so as to find the best assembly configuration that prevents separation.

Bilge System Design on 500 GT Ferry for Bulukumba–Selayar Route

A piping system is the main part of a system that connects the point where the fluid is stored to the point of accessing the pipe. Both pipe strength and pump capacity must be carefully considered because the safety of a ship will depend on the piping arrangement as well as on other ship equipment. The main function of the bilge pipe system is the drainage system in case of flooding in the compartment due to grounding or collision. Another function is the drainage system in the event of leaks on the welding root, condensation on the side shell leaks on the piping system (particularly in the engine room), and discharge water due to water-splash over the hatch. This study aimed to design a bilge piping system design using Autopipe Software with ASME B31.3 standard for the piping process. The design phase of the system is collecting data, then determining the load case. After that, selecting components needed for the construction of the system. The following step, making 3-dimensional modeling on Autopipe by entering input based on the determining components. Finally, validating the model, and proceed with the running model according to the specified load case. The result of the running model is the pipe stress level which is described in the stress code in the Autopipe. The final results are 3-dimensional drawings of the system and the number of components needed for constructing the system under Indonesian Classification Bureau (BKI) rules and ASME B31.3 standards for the piping process.

Risk Assessment Fishing Vessel Based for the Intact Ship Stability

Application of safety assessment and risk analysis using a risk-based approach for ship stability in ship operations at sea. However, there are currently no specific criteria and computational methods for risk assessment of ship stability. Based on the stability requirements for fishing activities at sea, the ship stability criteria will be explained in detail in this study. Calculation of stability used to obtain the GZ enforcement arm is carried out with the help of software for the shaking period using the International Maritime Organization (IMO) formula. Next, how to calculate parameters and determine certain coefficients for risk assessment of ship stability, and how to redraw the stability curve. Finally, proposed method is applied to ship model with comments and recommendations for monitoring to provide and overview. The study result indicate that the five loading conditions that occur on the ship have good stability by the criteria set by the International Maritime Organization (IMO). The value of GMt in each condition includes condition 1 and so on, 0.48; 0.48; 0.47; 0.46; 0.43. The results are presented in the form of F-N. Finally the sensitivity of the model is evaluated along with the assessment of associated uncertainties. The FN graph represents acceptable areas and unacceptable areas. Based on the results of data processing, the highest GM at GM Load-case 5 0.638 meters is in the Acceptable area. While Load-case 1 to Load-case 4 GM values sequentially Load-case 1: 0.487 meters; Load-case 2: 0.488 meters; Load-case 3: 0.47 meters; Load-case 4: 0.468 meters; is in an unacceptable area Unacceptable.

APPLICATION OF GRADIENT PROJECTION METHOD TO PARAMETRIC OPTIMIZATION OF STEEL LATTICE PORTAL FRAME

The paper has proposed a mathematical model for parametric optimization problem of the steel lattice portal frame. The design variable vector includes geometrical parameters of the structure (node coordinates), as well as cross-sectional dimensions of the structural members. The system of constraints covers load-carrying capacities constraints formulated for all design sections of structural members of the steel structure subjected to all ultimate load case combinations. The displacements constraints formulated for the specifiednodes of the steel structure subjected to all serviceability load case combinations have been also included into the system of constraints. Additional requirements in the form of constraints on lower and upper values of the design variables, constraints on permissible minimal thicknesses, constraints on permissible maximum diameter-to-thickness ratio for the structural members with circle hollow sections, as well as the conditions for designing gusset-less welded joints between structural members with circle hollow sections have been also considered in the scope of the mathematical model. The method of the objective function gradient projection onto the active constraints surface with simultaneous correction of the constraints violations has been used to solve the formulated parametric optimization problem. New optimal layouts of the steel lattice portal frame by the criterion of the minimum weight, as well as minimum costs on manufacturing and erection have been presented.

History, Evolution, and Future of Casing Design Theory and Practice

Casing design and the associated load assumptions have evolved considerably over the last 30 years. The objective of this paper is to trace the history, evolution and future of casing design by means of the type of load cases and the assumptions made for them as it evolved from the early 1960's to the modern load case requirements for wells drilled in the 2020's. The vast majority of tubular failures in oil & gas wells are not attributable to computational errors in calculating design loads, but rather are due to a shortfall in considering the appropriate load scenarios. One common shortfall includes making incorrect or oversimplified assumptions for the initial and final temperature and pressure conditions. There is no industry standard for casing or tubing design loads, but there is an industry accepted standard process for the calculation of the stress on tubulars once the load cases are determined. Each operating company may use a different set of load assumptions depending on the well type and risk assessment. This work also keeps in view the major computational tools used during each step change of the casing design evolution: slide rule/nomographs, HP 41C calculators, PC DOS and Windows programs, and the latest Cloud-Native paradigm with REST API's within a microservices architecture. A REST API (also known as RESTful API) is an Application Programming Interface (API) that conforms to the constraints of Representational State Transfer (REST) architectural style commonly used in current Cloud computing technology. The scope will also include ongoing research and development to address shortcomings of previous load case assumptions and calculations for extended reach and HPHT wells, closely spaced wells, and geothermal wells. Modern wells and modern casing design load cases are in a constant state of evolution and casing failures will occur unless engineers and their tools also evolve.