This course, based on the ASME Y14.5-2009 standard, provides an in-depth explanation of how to use tolerance stacks to analyze product designs and how to use geometric tolerances in stacks. You will learn the essential methods and concepts used for creating 1D part and assembly tolerance stacks.
Individuals responsible for quality management system, implementation, and auditing to the AS9100:2016 series of standards for Aviation, Space, and Defense will require an understanding of the requirements for the preparation and execution of the audit process as defined in these revised standards. Management and implementers of AS9100:2016 Rev. D within these organizations must also be aware of what these requirements mean for their company.
The avionics hardware industry world-wide is now commonly required to follow DO-254 Design Assurance Guidance for Airborne Electronic Hardware for literally all phases of development: Safety, Requirements, Design, Logic Implementation, V&V, Quality Assurance, etc. The DO-254 standard is a companion to the software DO-178B standard; however, there are many differences between hardware and software which must be understood. This basic course introduces the intent of the DO-254 standard for commercial avionics hardware development.
Sealant is applied between joined aircraft parts in the final stage of the assembly, before installation of permanent fasteners. In this paper a novel approach for aircraft assembly simulation is suggested, which allows to resolve transient interaction between parts and sealant in the course of airframe assembly process. The simulation incorporates such phenomena as compliance of parts, contact interaction between them and fluidity of sealant with presence of free surface. The approach based on fluid-structure interaction techniques consists of two basic steps: at first one pressure of sealant is found after corresponding fluid dynamics problem is solved and on second one displacements of parts and sealant are calculated through the solving of contact problem. Iterations between structural and fluid dynamics solvers are performed to achieve convergence. The developed approach is demonstrated on example of joining of two test aircraft panels.
Aircraft cabin operations shift towards data-driven processes. Cabin-wide multi-system communication networks are introduced to share required data for corresponding novel data-driven applications. Examples are data-driven predictive maintenance applications to reduce the downtime of systems and increase the period of scheduled maintenance or video analytics usage to detect a strained or unruly atmosphere amongst passengers. These applications require a network for transport of associated data and resources for actual computation. Costs and weight have always been the most important factors deciding if new services are introduced within the aircraft cabin. Thus, re-using hardware with free computation capacity that is already installed in the aircraft cabin can target both aspects, weight and costs. Examples for such hardware resources could be the In-flight Entertainment (IFE) equipment being installed in every seat.
Riveting is an essential process for the pre-assembly as well as the final assembly of aircrafts. In many cases, the riveting process fails to be fully automated, for instance, in parts with complex geometries. Thus, manual riveting is still widely common. Several works have been carried towards semi-automatic riveting solutions, namely in riveting the section barrel of the aft section to its pressure bulkhead. In , a method of communication-free semi-automated riveting is proposed where a partially autonomous robot performs counter-holding while a human worker rivets. The method has been modeled and tested extensively in simulation. However, although a demonstration prototype has been developed, models have been tested on it curtly. This paper investigates experimental evaluation of different model variations on demonstration. The aim is to identify the boundaries of the method in real world conditions.
A systematic and comprehensive first law analysis of a cooled gas turbine cycle subjected to vapor compressor inlet air cooling (VC-IAC) has been conducted in our study. Film air cooling technique has been implemented to cool the gas turbine (GT) buckets. The gas turbine is subjected to variation of various operating and ambient parameters and the corresponding effect is analyzed to find out the optimal one. The integration of VC-IAC has been reported to further enhance the plant specific work and plant efficiency of gas turbine cycle, the enhancement being higher in regions having a hot and dry climate. This increase in cycle performance due to VC-IAC has been found superior in case of bucket cooled GT cycle when compared to uncooled one. It has further been witnessed that the plant specific work increases by more than 0.35 % and the plant efficiency increases by little above 0.1 % for every 1o C drop in CIT.
The quest for achieving more efficient gas turbine engine systems (GTESs) has led the researchers to try getting into many new dimensions of research. Simple Brayton Cycle based plants were coupled with recuperators, regenerators and reheaters to avoid heat energy wastage and this formed Complex GTESs. Multistage compression in axial compressors and multistage expansions in turbines paved the path to optimize the plant design for greater thrust to weight ratio and greater efficiency of the GTESs. Since the increase in efficiency of any power plant is directly or indirectly related to temperatures at which the plant cycle is being operated, this thermodynamic constraint had led to the development of high temperature bearing materials such as single crystal Nickel based superalloys.
The traditional acquisition and development cycles of a weapon system by government agencies goes through multiple stages throughout the life cycle of the product. Over the last few decades, many of the United States military programs had experienced acquisition cost growth. Many studies by the Department of Defense indicates that the cost growth is a result of multiple factors including the development and manufacturing stages of the product. Organizations with multiple operation sites that goes across multiple states or even countries and continents are finding it increasingly difficult to share product technical and financial databases to ensure the corporate synergy between multiple sites or divisions. For such organizations, there exist the need to synchronize the operations and have standard and common database where everything is stored and equally accessed by different sites.
A new numerical approach is proposed for studying possible vibrations caused by drilling during the assembly of aircraft structures. It is based on modelling of the stress-strain state of assembled structures by solving the corresponding transient contact problem. This approach is intended for fast dynamic analysis of the structure in the drilling area. It includes a time discretization algorithm, a special reduction technique and a reformulation of contact problem in terms of quadratic programming. The high speed of the algorithm allows one to combine the non-stationary calculations with variation analysis in order to check the possible deviations in the shape of assembled parts. The proposed approach is validated by commercial software and it is also applied for analysis of a test problem.