Ben J Hicks

Energy method for modelling delamination buckling in geometrically constrained systems

Abstract Delamination buckling analysis of laminates is of considerable interest to the mechanical and materials engineering sectors, as well as having wider applications in geology and civil engineering. With advances in computing power, the ability to model ever increasingly complex problems at more detailed levels becomes more of a reality. However, many of the common finite element packages, with the exception of all but the most specialized, do not perform particularly well where complex non-linear problems are dealt with. In many cases, these packages can fail to determine the full range of solutions or accurately predict the properties and geometry of the final state. This is particularly the case where large deformations and buckling of laminates are considered. Because of this, many researchers prefer to use what they perceive to be more reliable techniques, such as the symbolic computation of the underlying differential equations, rather than finite element approaches. The use of finite element packages is further frustrated by the steep learning curve and implicit restrictions imposed by using third-party software. In this paper, a finite element approach and an energy formulation method are considered and used to model the delamination buckling in a geometrically constrained system. These methods are compared with experimental results and their relative merits are discussed. In particular, the accuracy and the ability to represent the geometry of the buckled system are discussed. Both the finite element approach and the energy formulation are described in detail and the numerical results are compared.

An energy-based approach for modelling the behaviour of packaging material during processing

Abstract This paper deals with the investigation of improved methods for considering machine-material interaction during the design and production of packaging machinery. Minimum energy principles are used to create a theoretical model of the response of the packaging material during processing. The complex non-linear properties of the packaging material are encapsulated in parametric models generated through analysis of the physical measurement of the changing properties during processing. These two techniques are incorporated into a software model that represents the behaviour of a skillet during the erection process. This software model considers the material, the pack design and the machine system. The overall modelling approach is validated by comparison with a physical system, which shows a good correlation with the theoretical model.

Constraint-Aided Product Design

The importance of supporting the early stages of design is widely accepted. In particular, the development of supportive tools and methods for modelling and analysis of evolving design solutions present a difficult challenge. One reason for this is the need to model both the product design and the design knowledge from which the design is created. There are a number of limitations with many existing techniques and an alternative approach that deals with the design constraints themselves is presented. Dealing directly with the constraints affords a more generalised approach that represents the process by which a product is designed. This enables modelling and reasoning about a product from an often abstract and evolving set of requirements. The constraint methodology is an iterative process where the design requirements are elaborated, the constraint rules altered, design ideas generated and tested as functional structures. The incorporation of direct search techniques to solve the constrained problem enables different solutions to be explored and allows the determination of ‘best compromises’ for related constraints. A constraint modelling environment is discussed and two example cases are used to demonstrate the potential of a constraint-aided approach for supporting important issues such as the design of product variants and product families.

Finite element simulation of folding carton erection failure

Abstract In response to recent European Union (EU) regulations on packaging waste, the packaging industry requires greater fundamental understanding of the machine-material interactions that take place during packaging operations. Such an understanding is necessary to handle thinner lighter-weight materials, specify the material properties required for successful processing and design right-first-time machinery. The folding carton industry, in particular, has been affected by the new legislation and needs to realize the potential of computational tools for simulating the behaviour of packaging materials and generating the necessary understanding. This paper describes the creation and validation of a detailed finite element model of a carton during a common packaging operation. The model is applied here to address the problem of carton buckling. The carton was modelled using a linear elastic material definition with non-linear crease behaviour. Air inrush suction, which is believed to cause buckling, was quantified experimentally and incorporated using contact damping interactions. The results of the simulation are validated against high-speed video of carton production. The model successfully predicts the pattern of deformation of the carton during buckling and its increasing magnitude with production rate. The model can be applied to study the effects of variation in material properties, pack properties and machine settings. Such studies will improve responsiveness to change and will ultimately allow end-users to use thinner, lighter-weight materials in accordance with the EU regulations.

The performance envelope of forming shoulders and implications for design and manufacture

Abstract The production of packaging machinery is a highly competitive global market driven by the ever-increasing demands of customers and legislation. The fundamental design principles of many packaging machines are the result of incremental improvements made over the last few decades. This paper looks at the underlying theory for forming shoulders and, starting with previously published results, determines the performance envelope relating to certain critical parameters. The findings are discussed in the light of their relevance for the creation of new designs.

Cost estimation for standard components and systems in the early phases of the design process

One of the most difficult tasks undertaken by the designer is to evaluate the cost of a design. This is a very important consideration in the design process, especially when the designer is trying to choose between alternatives, or optimising a particular solution. The designer must develop a design in order to fulfil the required performance characteristics as well as provide the appropriate quality at minimal cost. In order to better enable the designer to undertake this task, techniques for the cost estimation of a mechanical system from a description of the performance attributes for individual components is discussed. Three classes of engineering component are defined and methods for the cost forecasting of each class are proposed. These techniques are implemented in a system modelling tool, which provides a framework for multi-objective performance and cost optimisation of mechanical systems. It also enables the comparison of cost for various concepts at the early phases of the design process. The methods are validated through application to a range of mechanical components and an example case study is described.

A foundational observation method for studying design situations

Observational studies of designers play an important role in engineering design research, yet there is currently no accepted standard approach for comparing, combining, or contrasting studies. Consequentially, reuse, reanalysis, replication, and aggregation of data are limited and the potential impact of individual studies is severely constrained. This paper begins to address this issue by introducing and developing a foundational method for observational design research to improve replicability, reuse, and overall comparability of empirical studies. A three-step foundational method is proposed that covers capture, coding, and analysis. The capture step defines overall and situational context as well as multiple capture streams, generating a broad data-set that can be examined from multiple perspectives. The coding step employs a multi-level approach that seeks to minimise workload while describing both detailed and high-level information. The analysis step builds on the multi-level approach to provide for a flexible yet standardised examination of the data-set. The overall approach is introduced theoretically and illustrated using a comparison of an industrial study and an experimental study. Finally, it is argued that the proposed method promotes rigour, reliability, and standardisation; and could provide one means for improving comparison and aggregation, ultimately increasing impact in academia and practice.

The Modeling of Engineering Systems for Their Computer-Based Embodiment With Standard Components

Engineering products and systems consist of varying numbers of components, connecting elements, and structures. The effective design and selection of these is essential for the commercial success of a product. The designer or design team must consider not only physical attributes and performance capabilities but also economic considerations. Their ability to consider these various factors and explore an optimum solution is severely frustrated by the analytically intensive and time-consuming aspects of embodying a system. This embodiment process can become complex where a large number of what can be termed standard components are included. Thus the creation of supportive methods or tools to expedite the embodiment process with these standard components is particularly important. This paper presents a number of techniques that have been generated to enable the consideration of proprietary models of standard components within an overall systems modeling approach. This modeling approach aims to support the designer during the transformation of an idea into a product or system. In particular, this paper deals with the issues concerning the representation of a system as a whole while providing for the specification and/or selection of individual components from a variety of electronic representations. The method for representing a mechanical system is summarized and the general issues of interfacing proprietary electronic representations with a systems modeling tool are discussed. An approach is developed and the process of constructing a system model, selecting electronic representations, and system resolution are described. An industrial case study is used to demonstrate the ability of the approach to embody a system in an integrated and holistic manner. This enables the development of a more refined design solution and consequently more fully informed decisions, based on actual data, to be taken earlier in the design process.

An Exploratory Study into Automated Real-Time Categorisation of Engineering E-Mail

For large, spatially and temporally distributed engineering projects, e-mail is a central means for the discussion of engineering work and sharing of digital assets that define the product and its production process. The importance of communication and the value of its content for resolving issues post facto are universally accepted. More recently, the potential value of its content to predict events, issues and states a priori has been explored with some success. However, while in the former context (post facto) trends and patterns can be established through iteration and refinement over time, for prediction, heuristics need to be established in advance and closer to real-time analysis becomes necessary due to the critical and very often short timescales. It is this challenge of making predictions from the content of e-mail that is considered in this paper. In particular, the paper deals with engineering e-mail and the ability to automatically predict its purpose from its content rather than relying solely on the subject line. The work builds upon previous studies by the authors concerning the characterisation of the content of e-mail: what they are about, why they were sent and how the content is expressed. The paper summarises the previous work and looks at the potential of identifying the purpose of e-mail through the use of Naive Bayes and an adapted Latent Semantic Analysis approach. While the techniques have only been applied to an initial exploratory study of 98 e-mails, the results suggest the potential for automated real-time categorisation of engineering e-mails through achieving an accuracy of 66%. Such a capability would both support prioritisation of e-mail for engineers and macro level characterisation of project e-mail dynamics. The latter provides the opportunity for real-time analysis of an engineering projects status and correspondingly, modes of management intervention.

Modelling the Evolution of Computer Aided Design Models: Investigating the Potential for Supporting Engineering Project Management

The development of Computer Aided Design (CAD) models is a fundamental and distinct feature of Engineering Projects. CAD models can be considered to be the digital embodiment of the products’ design and are used to support a wide variety of tasks that span the embodiment, detail, manufacture and commissioning phases of a project. With this in mind, it is proposed that the monitoring and modelling of the edit trace behaviour of CAD files may provide additional understanding and evidence that supplements current approaches to monitor and manage engineering projects.