Implementation of dimensional management methodology and optimisation algorithms for pre-drilled hinge line interfaces of critical aero assemblies – A case study

A dimensional management procedure is developed and implemented in this work to deal with the identification of the optimum hole diameter that needs to be pre-drilled in order to successfully join two subassemblies in a common hinge line interface when most of the degrees of freedom of each subassembly have already been constrained. Therefore, an appropriate measure is suggested that considers the assembly process and permits the application of optimisation algorithms for the identification of the optimum hole diameter. The complexity of the mechanical subassemblies requires advanced 3D tolerance analysis techniques to be implemented and the matrix method was adopted. The methodology was demonstrated for an industrial, aerospace engineering problem, that is, the assembly of the joined wing configuration of the RACER compound rotorcraft of AIRBUS Helicopter and the necessary tooling needed to build the assembly. The results indicated that hinge line interfaces can be pre-opened at a sufficiently large size and thus, accelerate the assembly process whilst the suggested methodology can be used as a decision-making tool at the design stage of this type of mechanical assembly.

‘Do not expect me to stay quiet’: Challenges in managing a historical strategic resource

In this paper we explore how a historical strategic resource (HSR) could be used by an organization. We propose that within an organization, HSR is both an asset and an arena for power struggle. Our contributions stand at several levels at the crossroads of strategic management and organizational studies. First, we show the importance of various stakeholders in constructing a HSR. Second, we highlight its complexity due to its embeddedness with history. The fact that a HSR could be akin to a public good implies that its rents are difficult to control for organizations. To uncover what is meant by a historical resource, we first present a review of the resource-based theory and the uses of the past in organizations from the perspective of organization theory and organizational history. We then present our fieldwork, which focuses on Emmaus, a major charity organization in France, and its founder, Abbé Pierre. Based on a historical study covering the period 1949 to 2017 drawing on the organization’s archives, online publications and data from the French national audiovisual archives, we identify visual and rhetorical elements that constitute Abbé Pierre and his past as HSR for the Emmaus organization. Eventually, our paper contributes to the literature by offering a four-dimensional management framework for HSR with appropriation, ownership, maintenance and distancing.

Fuzzy Sensitivity Analysis in the Context of Dimensional Management

Real components always deviate from their ideal dimensions. This makes every component, even a serial production, unique. Although they look the same, differences can always be observed due to different scattering factors and variations in the manufacturing process. All these factors inevitably lead to parts that deviate from their ideal shape and, therefore, have different properties than the ideal component. Changing properties can lead to major problems or even failure during operation. It is necessary to specify the permitted deviations to ensure that every single product nevertheless meets its technical requirements. Furthermore, it is necessary to estimate the consequences of the permitted deviations, which is done via tolerance analysis. During this process, components are assembled virtually and varied with the uncertainties specified by the tolerances. A variation simulation is one opportunity to calculate these effects for geometric deviations. Since tolerance analysis enables engineers to identify weak points in an early design stage, it is important to know the contribution that every single tolerance has on a certain quality-relevant characteristic, to restrict or increase the correct tolerances. In this paper, a fuzzy-based method to calculate the sensitivity is introduced and compared with the commonly used extended Fourier amplitude sensitivity test (EFAST) method. Special focus of this work is the differentiation of the sensitivity for the total system and the sensitivities for the subsystems defined by the α-cuts of the fuzzy numbers. It discusses the impact of the number of evaluations and nonlinearity on sensitivity for EFAST and the fuzzy-based method.

Comparison of Different Sensitivity Analysis Methods in the Context of Dimensional Management

Although mass production parts look the same, every manufactured part is unique, at least on a closer inspection. The reason for this is that every manufactured part is inevitable subjected to different scattering influencing factors and variation in the manufacturing process, such as varying temperatures or tool wear. All these factors inevitably lead to parts, which deviate from their ideal shape. Products, which are built from these deviation-afflicted parts consequently show deviations from their ideal properties. To ensure that every single product nevertheless meets its technical requirements, it is necessary to specify the permitted deviations. Furthermore it is necessary to estimate the consequences of the permitted deviations, which is done via tolerance analysis. During this process the imperfect parts are assembled virtually and the effects of the geometric deviations can be calculated during a variation simulation. Since the tolerance analysis is to enable engineers to identify weak points in an early design stage it is important to know which contribution every single tolerance has on a certain quality-relevant characteristic, to restrict or increase the correct tolerances. In this paper two different approaches are shown and compared to represent the statistical behavior and the strongly connected sensitivity analyses. In particular a newly developed approach, which is based on fuzzy arithmetic, is compared to the established EFAST-method. The exemplary application of both methods and the comparison of the results are illustrated on a case study.

Reduction of Overwelding and Distortion for Naval Surface Combatants. Part 2: Weld Sizing Effects on Shear and Fatigue Performance

As high-strength thinner-steel implementation in ship designs increase, dimensional management becomes critical to control construction costs and schedule in ship production. In the U.S. shipbuilding industry, improvements to shipbuilding facilities and processing technology have not kept pace with the rate of change in ship design. Additionally, new designs using thinner steels are subject to legacy weld sizing criteria possibly leading to inappropriately sized welds on lightweight materials. These two factors result in widespread overwelding, causing severe plate deformation in naval vessels during construction and nonvalue added labor to correct as needed for fit-up tolerances. Historically, shear and fatigue strength data has been focused on the larger welds and thicker steel plates typical of the state of the practice when these legacy weld sizing criteria were developed. In order to optimize weld design and production in modern, lightweight naval surface vessels, there is a need to develop more accurate data about the performance of precision fillet welds for thin steels.

Research on the Multidimensional Accounting System Design Based on the Two-Dimensional Code Technology

The existing information management system may reduce the timeliness, objectivity and reliability of accounting information in business operations, internal control and information transfer and it cannot be effectively integrated with accounting information systems and other issues. In this paper, based on the theory of multidimensional accounting, we integrate the concept of barcode. And we take the forms dimension, accounting dimension and management dimension of economical business into the barcode design, building the accounting information systems of automated billing and multi-dimensional management