Design for Reliability and Maintainability Cost Model

Author(s):  
Basel Alsayyed Ahmad

In this paper, the author presents a cost model which simultaneously incorporates the abilities of two main designs. Namely, design for reliability (DfR) and design for maintainability (DfMn). DfR and DfMn have been of a great concern for designers. The focus has been more on the quality rather than aspects of reliability and maintainability of product development in general and product design in particular. However, as more awareness and attention is paid to the whole product lifecycle, more product lifecycle X-ability needs to be considered upfront at the design stage. To develop a new model, cost models of design for reliability as well as design for maintainability have been considered and evaluated. This new model, which tackles the two criteria simultaneously, has been developed and is a parametric model which allows for running sensitivity analysis based on the different aspects of reliability and maintainability.

1999 ◽  
Vol 103 (1026) ◽  
pp. 383-388 ◽  
Author(s):  
K. Gantois ◽  
A. J. Morris

Abstract The Paper describes a metal and composite recurrent cost model of a large civil aircraft wing structure for a multidisciplinary design, analysis and optimisation (MDO) environment. The work was part of a recent European MDO project (BE95-2056) which investigated methods for the integration of structures, aerodynamics, dynamics and manufacturing cost at the preliminary design stage. The paper discusses the cost modelling approach, which is based on parametric and process cost model methods, and the integration of the cost models into an MDO process. Results for the cost models are shown. A framework has been successfully developed which allows the incorporation of manufacturing cost models into an MDO environment. It allows a designer to evaluate cost changes with respect to specific design changes such as rib pitch, stringer pitch, wing area and wing sweep.


Author(s):  
Paul D. Thompson ◽  
Roberto Soares ◽  
Hong Jae Choung ◽  
Fazil T. Najafi ◽  
Richard Kerr

User cost models are used in bridge management systems to quantify, in economic terms, the potential safety and mobility benefits of functional improvements to bridges. One component of many such models is a formula to predict traffic accident risk on the basis of bridge characteristics such as roadway width and approach roadway alignment. A critical analysis of the user cost model used in AASHTO’s Pontis and Bridgit systems found that the model was overly sensitive to extremes of roadway width, yielding unrealistically high benefit estimates. A new model was developed using Florida data on bridge characteristics and traffic accidents. The new model has superior behavior and statistical characteristics on a full inventory of state highway bridges. Since it relies solely on National Bridge Inventory data items, the model is readily transferable to many different bridge management systems.


Author(s):  
Iván Díaz ◽  
Mark J. van der Laan

AbstractIn this article, we present a sensitivity analysis for drawing inferences about parameters that are not estimable from observed data without additional assumptions. We present the methodology using two different examples: a causal parameter that is not identifiable due to violations of the randomization assumption, and a parameter that is not estimable in the nonparametric model due to measurement error. Existing methods for tackling these problems assume a parametric model for the type of violation to the identifiability assumption and require the development of new estimators and inference for every new model. The method we present can be used in conjunction with any existing asymptotically linear estimator of an observed data parameter that approximates the unidentifiable full data parameter and does not require the study of additional models.


Author(s):  
Cristian Iorga ◽  
Alain Desrochers

The expansion of the markets corroborated with product customization and short time to launch the product have led to new levels of competition among product development companies. To be successful in the globalization of the markets and to enable the evaluation and validation of products, companies have to develop methodologies focused on lifecycle analysis and reduction of product variation to obtain both quality and robustness of products. Keywords: Modeling, Evaluation, Validation, Design ProcessThis paper proposes a new design process methodology that unifies theoretical results of modeling stage and empirical findings obtained from the validation stage. The evaluations and validations of engineering design are very important and they have a high influence on product performances and their functionality, as well on the customer perceptions.Given that most companies maintain the confidentiality of their product development processes and that the existing literature does not provide more detailed aspects of this field, the proposed methodology will represent a technical and logistical support intended for students or engineers involved in academic as well as industrial projects.A generic methodology will be refined based on a new approach that will take into consideration the specification types (quantitative or qualitative), the design objectives and the product types: new/improved, structural/esthetic. Hence the new generic methodology will be composed of specific product validation algorithms taking into account the above considerations. At the end of this paper, the improvements provided by the proposed methodology into the design process will be shown in the context of the engineering student capstone projects at the Université de Sherbrooke.


2013 ◽  
Vol 29 (1) ◽  
pp. 61-85 ◽  
Author(s):  
Patricia Everaert ◽  
Dan W. Swenson

ABSTRACT This active learning exercise simulates the target costing process and demonstrates how a management theory (goal setting theory) is relevant to a business improvement initiative (target costing). As part of the target costing simulation, student participants work in teams to address a business issue (product development) that moves across functional boundaries. The simulation begins with students learning how to assemble a model truck and calculate its product cost using activity-based costing. Students are then divided into teams and instructed to reduce the truck's cost through a redesign exercise, subject to certain customer requirements and quality constraints. Typically, the teams achieve cost reduction by eliminating unnecessary parts, by using less expensive parts, and by using less part variety. This exercise provides a unique opportunity for students to actively participate in a redesign exercise. It results in student teams creating a wide variety of truck designs with vastly different product costs. The case ends by having a discussion about target costing, goal setting theory, and the implications of the target costing simulation. This simulation contains a number of specific learning objectives. First, students learn how the greatest opportunity for cost reduction occurs during the product design stage of the product development cycle. Second, students see firsthand how design-change decisions affect a product's costs, and the role of the cost information in guiding those decisions. Third, students experience the cross-functional interaction that occurs between sales and marketing, design engineering, and accounting during product development. Finally, this exercise helps students understand the concept of target costing. The simulation is appropriate for undergraduate or graduate management accounting classes. Data Availability:  For more information about this case, contact the first author at [email protected].


2021 ◽  
Vol 1 ◽  
pp. 2691-2700
Author(s):  
Stefan Goetz ◽  
Dennis Horber ◽  
Benjamin Schleich ◽  
Sandro Wartzack

AbstractThe success of complex product development projects strongly depends on the clear definition of target factors that allow a reliable statement about the fulfilment of the product requirements. In the context of tolerancing and robust design, Key Characteristics (KCs) have been established for this purpose and form the basis for all downstream activities. In order to integrate the activities related to the KC definition into product development as early as possible, the often vaguely formulated requirements must be translated into quantifiable KCs. However, this is primarily a manual process, so the results strongly depend on the experience of the design engineer.In order to overcome this problem, a novel computer-aided approach is presented, which automatically derives associated functions and KCs already during the definition of product requirements. The approach uses natural language processing and formalized design knowledge to extract and provide implicit information from the requirements. This leads to a clear definition of the requirements and KCs and thus creates a founded basis for robustness evaluation at the beginning of the concept design stage. The approach is exemplarily applied to a window lifter.


2017 ◽  
Vol 5 (1) ◽  
pp. 54-67 ◽  
Author(s):  
Alain Pfouga ◽  
Josip Stjepandić

Abstract With their practical introduction by the 1970s, virtual product data have emerged to a primary technical source of intelligence in manufacturing. Modern organization have since then deployed and continuously improved strategies, methods and tools to feed the individual needs of their business domains, multidisciplinary teams, and supply chain, mastering the growing complexity of virtual product development. As far as product data are concerned, data exchange, 3D visualization, and communication are crucial processes for reusing manufacturing intelligence across lifecycle stages. Research and industry have developed several CAD interoperability, and visualization formats to uphold these product development strategies. Most of them, however, have not yet provided sufficient integration capabilities required for current digital transformation needs, mainly due to their lack of versatility in the multi-domains of the product lifecycle and primary focus on individual product descriptions. This paper analyses the methods and tools used in virtual product development to leverage 3D CAD data in the entire life cycle based on industrial standards. It presents a set of versatile concepts for mastering exchange, aware and unaware visualization and collaboration from single technical packages fit purposely for various domains and disciplines. It introduces a 3D master document utilizing PDF techniques, which fulfills requirements for electronic discovery and enables multi-domain collaboration and long-term data retention for the digital enterprise. Highlights With their practical introduction by the 1970s, virtual product data have emerged to a primary technical source of intelligence in manufacturing. Modern organization have since then deployed and continuously improved strategies, methods and tools to feed the individual needs of their business domains, multidisciplinary teams, and supply chain, mastering the growing complexity of virtual product development. As far as product data are concerned, data exchange, 3D visualization, and communication are crucial processes for reusing manufacturing intelligence across lifecycle stages. Research and industry have developed several CAD interoperability, and visualization formats to uphold these product development strategies. Most of them, however, have not yet provided sufficient integration capabilities required for current digital transformation needs, mainly due to their lack of versatility in the multi-domains of the product lifecycle and primary focus on individual product descriptions. This paper analyses the methods and tools used in virtual product development to leverage 3D CAD data in the entire life cycle. It presents a set of versatile concepts for mastering exchange, aware and unaware visualization and collaboration from single technical packages fit purposely for various domains and disciplines. It introduces a 3D master document utilizing PDF techniques, which fulfills requirements for electronic discovery and enables multi-domain collaboration and long-term data retention for the digital enterprise. 3D interoperability makes an important contribution to engineering collaboration. Several formats made to that end successively deal with challenges of their time. Some of these such as STEP are highly verbose formats, which gradually encapsulate all information necessary to define a product, its manufacture, and lifecycle support. Others are focusing best on lightweight visualization use cases and endure better with increasing size and complexity of data. Traditional formats like STEP and JT, though, are not capable of supporting the publishing activity in even broader fashion. New tendencies therefore are aiming at strengthening these individual formats through combination with complementary standards or by using document-based approaches. Unlike STEP or JT, 3D PDF can serve multiple purposes and leverages 3D data downstream throughout the product lifecycle to create, distribute and manage ubiquitous, highly consumable, role-specific rich renditions. Based on its container structure, 3D PDF is a fundamentally different approach from traditional experience established in product development – it is an exceptionally proficient contextual aggregation of multi-domain and multi-disciplinary product data. The manufacturing community should embrace it as an addition and great improvement to current engineering collaboration standards. All engineering components required for its descriptions are meanwhile published international standards. The productive use of 3D PDF for sure requires a change in the current mode of operation, be it simply because the traditional CAD model promptly demands new technical descriptions. More perspectives, which have not been primary focus of this approach need to be addressed in order to implement the 3D digital master concept of this paper in the industry. For the complete process to work properly, the actual workflows of today's business organizations must succeed a readiness check involving enhanced technical documentation capabilities of the authoring (CAx) applications based on 3D, PLM, and manufacturing workflows as well as new ways for engineering data communication with supply chain partners in the digital enterprise.


2016 ◽  
Vol 43 (4) ◽  
pp. 287-293 ◽  
Author(s):  
Yong-Woo Kim ◽  
Seung-Heon Han ◽  
June-Seong Yi ◽  
SooWon Chang

The effect of ‘supply chain management’ can be leveraged when benefits of collaboration within and beyond the capacities of individual organizations are witnessed. One of the primary tasks in reducing total supply chain costs is to understand where the costs occur in a supply chain and how each activity impacts the total supply chain costs. Most supply chains in construction usually involve multiple entities, each one in a different process. A rebar supply chain is one example where many entities are involved in different processes. The supply chain coordinator needs a supply chain cost model, which shows how each activity impacts all supply chain costs to reduce the total costs. The research suggests a supply chain cost model using time-driven activity-based costing. The proposed cost model was applied to a building construction project, followed by sensitivity analysis identifying critical activities. This method can be adapted to analyze other fragmented material supply chains in the construction industry.


Author(s):  
Jungmok Ma ◽  
Minjung Kwak ◽  
Harrison M. Kim

The Predictive Product Lifecycle Design (PPLD) model that is proposed in this paper enables a company to optimize its product lifecycle design strategy by considering pre-life and end-of-life at the initial design stage. By combining lifecycle design and predictive trend mining technique, the PPLD model can reflect both new and remanufactured product market demands, capture hidden and upcoming trends, and finally provide an optimal lifecycle design strategy in order to maximize profit over the span of the whole lifecycle. The outcomes are lifecycle design strategies such as product design features, the need for buy-backs at the end of its life, and the quantity of products remanufacturing. The developed model is illustrated with an example of a cell phone lifecycle design. The result clearly shows the benefit of the model when compared to a traditional Pre-life design model. The benefit would be increased profitability, while saving more natural resources and reducing wastes for manufacturers own purposes.


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