Katie Grantham Lough

The risk in early design method

Risk assessments are necessary to anticipate and prevent accidents from occurring or repeating. Current probabilistic risk assessment methods require mature design proposals to analyse. Since product safety and reliability are affected the most by decisions made during the early design phases, a risk assessment that can be performed with less mature data during these design phases is needed. This study focuses specifically on the relationship between function and risk in early design by presenting a mathematical mapping from product function to risk assessments that can be used in the conceptual design phase. An investigation of a spacecraft orientation subsystem is used to demonstrate the mappings. The results from the study and its spacecraft application yield a preliminary risk assessment method that can be used to identify and assess risks as early as the conceptual phase of design. The preliminary risk assessment presented in this paper is a tool that will aid designers by identifying risks as well as reducing the subjectivity of the likelihood and consequence value from a risk element, will provide four key risk element properties (design parameter, failure mode, likelihood, and consequence) for numerous risk elements with simple calculations, and will provide a means for inexperienced designers to effectively address risk in the conceptual design phase.

The Risk in Early Design (RED) Method: Likelihood and Consequence Formulations

This study focuses specifically on the relationship between function and risk in early design by presenting a mathematical mapping from product function to likelihood and consequence risk assessments that can be used in the conceptual design phase. An investigation of a spacecraft orientation subsystem is used to demonstrate the proposed mappings. The risk assessment presented in this paper is a tool that will aid designers by identifying risks as well as reducing the subjectivity of the likelihood and consequence value from a risk element, provide four key risk element properties (design parameter, failure mode, likelihood, and consequence) for numerous risk elements with a simple calculation, and provide a means for inexperienced designers to effectively address risk in the conceptual design phase. The investigation demonstrates that the method presented in this paper is a useful tool for preliminary identification and assessment of product risks.Copyright

Prescribing and Implementing the Risk in Early Design (RED) Method

To aid designer’s abilities to increase product safety and reliability, risk assessments need to be moved forward to the conceptual design phase of a product. This is especially difficult because often the product has not assumed a physical form in this design stage. In an effort to perform risk assessments based on function, rather than physical components, the risk in early design (RED) method was developed. This paper presents the function based mathematical mappings of the RED method for preliminary risk assessments based on catalogued historical failure information. An example of the RED preliminary risk assessments on a thermal control subsystem along with heuristics for applying the particular types of risk assessments are discussed. Finally, the steps for performing RED in the conceptual design phase are offered. The heuristics and steps for preliminary risk assessments shown offer a method for identifying potential areas of concern in a product during the early stages of design when much can be done to over come them.Copyright

Applying Function-Based Failure Propagation in Conceptual Design

When designing a product, the earlier the potential risks can be identified, the more costs can be saved, as it is easier to modify a design in its early stages. Several methods exist to analyze the risk in a system, but all require a mature design. However, by applying the concept of “common interfaces” to a functional model and utilizing a historical knowledge base, it is possible to analyze chains of failures during the conceptual phase of product design. This paper presents a method based on these “common interfaces” to be used in conjunction with other methods such as Risk in Early Design in order to allow a more complete risk analysis during the conceptual design phase. Finally, application of this method is demonstrated in a design setting by applying it to a thermal control subsystem.Copyright

Validating Module Heuristics on Large Scale Products

Decreasing time and costs is a major objective in many businesses today. Including modularity in the early design phases can effectively decrease time spent on and costs associated with a project. The task of identifying modules within a product early in the design process (when decisions are less expensive) is made less daunting by using the techniques of functional modeling and module heuristics. This paper discusses the results of the initial efforts to verify the module heuristics on large products (products with functional models consisting of more than 30 sub-functions) since the module heuristics were originally developed on small products. Observations on needed modifications to the functional modeling technique and original module heuristics are reported along with an investigation of using potential risk statements to formulate modules. This work finds the original module heuristics do apply to large products with modifications and combining of heuristics.Copyright

Comparing Component Functional Template Modeling Experimental Results in an Undergraduate Level Engineering Design Course

Component functional templates are a foundational tool, for the functional modeling method, that novice users can implement to develop functional modeling skills and produce better results by not requiring the modeler to have extensive background knowledge in the method. The templates provide common function layouts of ordinary electromechanical components that are based on historic data collected from design information on a wide range of consumer products. A previous experiment has been performed on a sophomore level design class to assess the change in quality between functional modeling results with and without the use of component functional templates. To address further evaluation of the usefulness the templates, another experiment was performed on multiple sections of an undergraduate engineering design course, controlling the amount of time that the students are exposed to the templates, in order to eliminate any extended exposure biases in the models using the templates. Quality and accuracy of the resulting models were gauged using a metric consisting of function structure, number of functions, flow representation through a chain, and product representation (the same metric used in the previous experiment). The results show that the students using the component functional templates consistently made fewer mistakes in their models in all categories than those that did not use them and thus, produced better models in terms of quality and accuracy.Copyright

Representing Historically Based Component-Function Relationships Through Design Templates

Functional analysis of systems is a common engineering application during different stages of design. Conceptual designers as well as post-development designers use the process to gather useful information about the system that is under consideration. The functional basis and component taxonomy are collective approaches to describe these systems in unique languages. Since many designers naturally think in terms of physical components, it is more difficult for them to grasp fundamental concepts necessary to functionally model a system properly. A new design instrument, component functional templates, has been developed as a means to link the functional basis and component taxonomy together in one coherent visual form that can be used by novice designers as an invaluable skill-building tool. Principal components analysis (PCA) is used to extract historical data from many consumer products whose design information has been stored in an online repository produced by the UMR Design Engineering Lab. This paper presents the approach and derivation of the templates, along with valid examples of template groupings that result from the analysis. An application of the templates is presented in a case study on the drive train of a bicycle where the templates prove to sufficiently begin the modeling process and provide room for unique manipulation that accurately describes functional requirements of the subsystem.Copyright

The Part Count Tool (PACT) for Concept Selection

This paper presents a part count tool that automates the consideration of manufacturing cost during the conceptual design phase by predicting part count for a particular product concept. With an approximate number of parts per product in the conceptual design phase, the designer can estimate the cost associated with the product. On the basis of the cost, the designer can make changes according to budget requirements. The part count tool will also aid in ranking the design concepts by number of components for a product. This tool utilizes existing automated concept generation algorithms to generate the design concepts. It extracts the available data from the Missouri S&T Design Repository to compute an average number of parts per component type in the repository and then calculates an average part count for new concepts. This data can subsequently be used by designers to estimate product cost. The part count tool also uses an algorithm to determine how to connect two non compatible components through the addition of mutually compatible components. While emphasis is placed on the average parts per product in evaluating designs, the overall functional requirement of the product is also considered.Copyright

Identifying Risk at the Conceptual Phase of Product Design: A Software Solution

This paper introduces RED (Risk in Early Design) software developed by the R.I.S.K by Design Lab at University of Missouri-Rolla. The RED software is a risk analysis tool that enables failure prevention to begin during the conceptual phase of product design. The main focus of the paper is describing the software architecture and application. Its unique graphical user interface allows designers to simply select the functions of the system being designed and the software immediately generates a risk analysis report. This analysis categorizes risk likelihood and consequence elements for a product by translating the recorded information about function and failure. An example describing the software’s use in the design process is also presented.Copyright

Assessing the brand meaning of an interdisciplinary engineering programme through a branding method

This paper presents the brand status of the Interdisciplinary Engineering (IDE) degree programme at Missouri University of Science and Technology (Missouri S&T), formerly the University of Missouri-Rolla (UMR). The IDE degree was founded in 2005 at UMR to meet the emerging need to provide considerable flexibility to students allowing them to construct programmes of study in areas of interest while maintaining a foundation in mechanics, thermal science, electrical networks and linear systems. This paper presents the brand status of the IDE BS degree among prospective and current students, academic faculty, and industry, and weighs it against the original implementation plan proposed in 2005 and provides the current perception of the degree programme at Missouri S&T.