Keeping up to date with the gold standard of materials reference data

Posted on August 26, 2016 by John Downing

The world of materials never stands still. New technological challenges constantly drive the need to explore new materials that offer properties that no existing material can deliver. It is vital to maintain a single, up-to-date source of materials property data, to keep abreast of all these new developments. How else can you ensure that your designers and engineers have the data they need for materials selection, product design, simulation, qualification, and more?

While new materials are constantly appearing, they may have spent many years in the development pipeline. For example, the size, loads and targeted weight of the Airbus A380 – the world’s largest passenger airliner with a wingspan of almost 80 metres and a capacity for 544 passengers – demanded a complete series of new aluminum alloys for the wing and fuselage. Development, qualification, and production of these advanced alloys took seven years.

The Airbus A380, the world’s largest passenger airliner. (© Airbus SAS 2016).

Focusing on just one part of the aircraft structure, the lower fuselage, the design criteria included static strength, buckling stability, and corrosion resistance. An aluminum alloy 6156 was developed for this application. Because the alloy needed high strength, a T6 temper was required, and it had to be clad to avoid intergranular corrosion. When compared to a similar sheet alloy, the new 6156 Clad-T62 was shown to have a 10% toughness benefit.

When considering new materials, it is important to understand potential challenges in using them, as well as their benefits. The property chart, created with Granta’s CES Selector™, is one way to do this—plotting tensile strength against elongation shows that the high strength and toughness of 6156 Clad-T62 alloy is achieved at the expense of a lower elongation, meaning the material will be more difficult to form than other materials. Because CES Selector draws on an up-to-date source of metals property data, it enables a complete analysis of these new materials, comparing them to existing materials and understanding both their benefits and disadvantages.

Plotting tensile strength against elongation shows the strength and toughness benefits of the 6156 Clad-T62 alloy are accompanied by a reduction in elongation, indicating that forming may be more difficult.

New materials occupying new parts of the material space are being developed as we continuously push the boundaries of engineering – and, keeping pace, Granta’s reference data is updated constantly with information from widely-used and respected sources. The recently-released metals data library is the most comprehensive yet, covering thousands of metal standards, specifications, and grades, and includes a digital version of the MMPDS-10 aerospace alloy data.

Dr Sarah Egan, Product Manager for Data Product Solutions at Granta, explains the motivation for Granta’s data project: “Whether it’s engineering driving materials development, or materials development driving engineering, it is always exciting to learn about how modern materials are enabling new technologies. But, more importantly, our customers need up-to-date and high-quality data on those materials to support their engineering processes.”

The new metals data also includes the latest Register of European Steels, sheet steels data, and enhanced international equivalency information to help find a local grade, for example, for use in an international manufacturing facility. Users of the GRANTA MI™ material information management system can access the data modules alongside proprietary data to create a complete materials information source for their engineering process.

Along with metals data, GRANTA MI and CES Selector users can access extensive data on plastics, ceramics, and composites, enabling comparisons and analysis across all material classes. With all of this up-to-date materials data easily accessible in one place, to search, analyze, and manipulate, users have the gold standard of materials reference data at their fingertips.

Integrating materials information in CAD and PLM

Posted on June 8, 2016 by John Downing

“I’ve been working in materials information technology since 1987 and the last year has been notable for greatly increased interest and engagement from companies who want to integrate managed materials information with their PLM and enterprise CAD process.” So said Granta’s Dr Arthur Fairfull as he introduced his presentation to an impromptu crowd of around 200 on the show floor at this week’s PTC LiveWorx event in Boston.

A crowded Granta booth at the PTC event was further evidence of this interest, following on from similar interest at the recent Siemens PLM Connection in Orlando—an event which included a number of in-depth sessions on materials information management.

Standing room only at Arthur Fairfull’s talk, ‘Materials knowledge management – for engineering, cost, and sustainability – for Creo and Windchill’ at LiveWorx.

I caught up with Arthur, who is Product Director for Materials Strategy & PLM Integration at Granta, to ask him about the latest trends and what is driving the greater focus on materials.

“There is a growing awareness within enterprises of their materials information challenges, and the need for a systematic approach to addressing them, integrated with their design and product development software environment,” he explains. “People are saying to us: ‘We need help to integrate materials information management with our CAD and PLM’. They know that challenges like substance legislation compliance, lightweighting, and cost reduction all depend on materials.”

At the recent conferences, Granta was presenting two major enhancements in materials support for CAD, CAE and PLM that provide product development teams with enhanced access to reliable, controlled materials data, thus saving time and improving the consistency and quality of materials decisions.

The first was the latest version of GRANTA MI:Materials Gateway embedded applications for direct end-user access to corporate materials information from within a broad range of CAD, CAE, and PLM systems, supporting fast product analytics and accurate simulation. Version 4.1 further enhances the user experience, including extremely responsive database browsing, and tools to allow new material requests directly from the CAD or PLM environments. The second enhancement was a new integration option, MI:Enterprise Connect for Teamcenter®, that enables automated enterprise-level synchronization of approved materials datasets from the GRANTA MI materials information management software into Teamcenter PLM.

Materials information management needs to support and fit the real-life environment—most manufacturers have several different CAE tools, often more than one CAD system, especially if they have grown by acquisition, and in some cases more than one PLM environment. MI:Materials Gateway currently supports: the CATIA®, Creo®, Inventor®, and NX® CAD systems; Abaqus/CAE®, ANSYS®, HyperMesh® and NX® CAE software; and Teamcenter® and Windchill® PLM.

GRANTA MI:Materials Gateway allows users to access and apply vital materials data, quickly and traceably, within CAD, CAE, or PLM software.

Dr Fairfull points out that there is no ‘one size fits all’ solution. So the latest Granta software releases aim to enhance support for different implementation strategies and solution architectures as companies build and deploy corporate ‘gold sources’ for material intelligence.

Navigating this complex space can be difficult, so Granta have written a new White Paper, ‘Material Intelligence for Enterprise CAD and PLM’, which examines the trends and best practices in CAD, PLM, and materials information management, and identifies key requirements for integrating these technologies, along with examples of addressing this challenge using the GRANTA MI product suite.

Dr Fairfull again: “We have integrated products that embed Granta technology in CAD and PLM and enable users to have direct access to the materials information they need. As individual users they save time and, because they are following a strategy laid down by their materials experts to use preferred materials, their company also benefits from greatly enhanced consistency and traceability.”

He highlighted that the White Paper includes a checklist of considerations for organizations planning materials integration with CAD and PLM, which customers were finding particularly helpful.

Easing the process of composites qualification

Posted on March 11, 2016 by John Downing

Watching a recent Granta webinar*, it struck me that composites qualification is a huge, and often very expensive, undertaking.

Dr Donna Dykeman, Senior Project Manager for Collaborative R&D at Granta, told me just how huge this task can be: “The process sensitivity of the composite, and its directional property capabilities, mean that a single material qualification program could result in more than 1,300 tests.”

Enterprises that want to support qualification workflows and protocols need to manage large volumes of test and analysis data associated with qualification programs, and combine this proprietary data with reliable reference data. Dr Dykeman said that access to qualified materials data to support composites qualification can be near impossible for some members of the supply chain without the support of publicly-funded programs, due to the time and cost involved. One source of data is the US National Center for Advanced Materials Performance (NCAMP) – this world-leading composite testing centre, established in 2005, brings together datasets of materials and process specifications, material pedigree data, test results, and reports that can be shared throughout the supply chain.

Experts from the National Institute for Aviation Research (NIAR), at Wichita State University, explained in the webinar that OEMs were qualifying their own materials prior to NCAMP (and its predecessor AGATE, which first adopted the shared database approach in 1995). This resulted in the repetition of testing, and it could be many years before the data was submitted to the Composite Materials Handbook (CMH-17), the leading source of composite test data.

Map of Granta schema for capturing composite data

Through NCAMP, each material is qualified once, with the data made available to CMH-17 without delay. This has widespread benefits, including:

for materials suppliers: cost savings, and the publication of key materials properties
for materials users: availability of published properties for materials selection, initial design and analysis, as well as cost and time savings
for governments: a reduced workload by eliminating redundant materials qualification programs, and improved safety by leveraging industry experts.

Through a long-standing collaboration, Granta provides enterprises with digital access to the NCAMP data from within the GRANTA MI materials information management system, making it quick and easy to browse, query, and apply through a simple web browser user interface.

Comparing composites compression test data in the new Composites QED data module.

Granta’s new Composites QED data module, launched in February 2016, added more than 7,500 unpublished NCAMP raw data curves in response to industry demand for more of this reference information. This data supports materials selection and screening, the generation of design allowables, and it also eases composite qualification by enabling comparison of in-house tests with tests for similar, established systems. Users can eliminate invalid test results or establish equivalency, demonstrating that their process produces the same properties as a proven material.

The NCAMP curves in Composites QED currently cover six of the most popular materials, including Cytec materials and 8552/IM7 (carbon fiber/epoxy). Granta will add data for a further 20 materials in due course, providing more than 40,000 curves for the 26 materials – and as new NCAMP data is published, Composites QED will be kept up to date.

The unique combination of NCAMP’s ever-expanding reference data and Granta’s material information management supports a rigorous, traceable, documented process, from test request through design allowable to qualification.

* View the webinar, Supporting composites qualification and equivalency processes (recorded in February 2016), on-demand at http://www.grantadesign.com/webseminars/2016/qualification.htm

CES Selector – two decades of progress, with more to come

Posted on February 2, 2016 by John Downing

“I was looking at every material possible, calling suppliers, trying to get hold of materials and price lists. With CES Selector, I could have saved months and months of work!”

That is what Dr Charlie Bream told me about several materials selection projects in his 14-year career prior to joining Granta in 2007, developing aerospace, automotive and consumer products – he had never used CES Selector until that point, now he is the Product Manager.

It is 22 years since Granta was founded as a Cambridge University spinout and every year since has brought new features and enhancements to CES Selector, Granta’s PC software for smart materials decisions. Its genesis was a decade earlier in Prof Mike Ashby’s ground-breaking idea for an application to find, explore and plot materials data. That evolved into CES EduPack, a standard teaching tool in universities for a generation of undergraduate materials students, many of whom now use CES Selector in industry and research.

A graphic from an earlier version of the CES software, from the 1990s.

Showing how far the software has come: The charting and annotation tools in CES Selector 2016 enable users to create informative charts that help to understand and communicate the benefits of material choices.

In 2007, Charlie says CES EduPack and CES Selector had the same functionality and, while they retain common features, they have developed separately, but in parallel, to meet different user requirements. Charlie says: “With CES EduPack, the emphasis is on making students think so that they understand the underlying principles, rather than giving them direct links to the answers. In industry, where people are using the product on a daily basis, they don’t want to derive things from first principles every time – they need tools that quickly provide the information they need.”

The evolution of CES Selector is driven by responding to customers’ needs. The Favourite Materials option originated from one firm’s request to flag up their most commonly used materials in their database. Other notable enhancements that Charlie mentions include improved reporting and charting, ever-expanding data sets, the Custom Subsets that enable users to focus studies on particular materials of interest, and the Performance Index Finder, which makes it quick and easy for the user to specify their engineering application during materials selection. The Find Similar Tool has been met with very positive feedback, allowing users to find a drop-in replacement to meet their constraints, or find similar grades of materials – particularly when you have material supply issues and need to find alternative with the same performance and processing characteristics.

One example of adding functionality is the Engineering Solver, which ‘speaks the language of engineers’. Charlie says: “Many engineers think in terms of geometry and load conditions rather than material properties – this tool converts these engineering properties into material properties, enabling them to readily search for appropriate materials.”

This tool, and Find Similar, are examples of how Granta is extending the capability to cover a wider range of scenarios and use cases. It is quick and easy to do a ‘what if’ scenario check, and the Comparison Table offers what Charlie calls a ‘sanity check’ to answer the question: “What have I forgotten?” He says: “It is the things that you have overlooked that are most likely to cause you a problem as you take the product forward to production.”

CES Selector provides an evidence base that gives users confidence in their materials choices, and they also have the tools and information to communicate their decisions to colleagues. Charlie says future developments will focus on adding more ‘material intelligence’, outputting more information about the impact a material choice has on the design – for example, how the required wall thickness changes with material, or for a fixed design, how the mass, cost and natural resonance varies with material. Charlie says: “These are all things that a designer/engineer needs to know when considering new materials.”

CES Selector has come a long way since 1994 but Granta is always listening to users and thinking of how to make it even better.

Two views, one vision – designers and engineers making great products

Posted on December 14, 2015 by Hannah Melia

If two heads are better than one, imagine the benefits of two communities coming together to share each other’s views on materials and processes to make the best designed, best engineered products. That’s the premise behind a new educational project at Granta Design.

If we can inspire designers and engage engineers to learn about each other’s vital role in product development, and enable them to communicate in the common language of materials, we can arrive at a whole that is much greater than the sum of the parts. Two views, one vision. The new CES EduPack ‘Products, Materials and Processes’ Database offers university educators and their students two views of materials information, the Designer’s View and the Engineer’s View, so both can learn how to create successful products that are functional and aesthetically pleasing.

The database runs inside the CES EduPack 2016 software and opens with a gallery of colorful, innovative products, some chosen because they use new materials, or use existing materials in new ways, or because they tell a story. A student who is intrigued by a cool product, and motivated by seeing how successful designs create wealth for companies and satisfaction for consumers, can click on an image to get more details on the product, its design, its designer, how was made and the materials used.

Granta asked industrial design experts to help develop the database. One said: “This link from products to materials is really important. This is really beautiful, because it is providing easy ways of doing it. Designers are always doing this, trying to find out for themselves: ‘What kind of material is this product made of?’”

Students can connect with the design of the iMac, the iconic computer that required designer Jonathan Ive and Apple to explore different polymers and molding technologies. Or with the Smart city-coupe, the car with polymer body panels that can be colored, removing the need for paint.

In the Designer’s View (above), an image illustrating a typical use of the material is shown along with a description, density and price data. This is followed by aesthetic attributes, such as tactile warmth, touch and flex. These are related to things students can feel for themselves – glass in a window pane is cold to the touch, an aluminum drink can is light but strong – and the attributes are presented objectively rather than being subjective. In the Engineer’s View (below), students quickly access reliable mechanical, thermal, electrical and eco properties of materials. Design guidelines and typical uses offer them more context.

Using the software, aesthetic and engineering attributes can be used to select a material for a given application using the systematic tools and methods developed by Professor Mike Ashby. The Eco Audit Tool helps students to consider the environmental and cost implications. By taking account of all these aspects, students can better appreciate products such as the Koziol Kasimir hedgehog cheese grater (pictured below), which can be sold at a price far above the cost of a piece of injection-molded plastic by bringing together form and function to make kitchen work both fun and effective.

Fun and effective: The Koziol Kasimir hedgehog grater. (Image courtesy of Koziol)

The Products, Materials and Processes Database enables students to appreciate that industrial designers and engineers both add value to a product, not just by making it functional, but also by making a human connection. In a world where many students will work in multi-functional teams in industry, that is a lesson well worth learning as early as possible in their careers.

Clearing the conceptual hurdle to collaboration

Posted on November 18, 2015 by John Downing

Originating from a research environment at Cambridge University, it’s in Granta’s DNA to collaborate with researchers, academics and other companies, and to enable such collaboration between other organizations.

But when I spoke to Dr James Goddin, who leads Granta’s collaborative R&D team, he said partners in collaborative projects can be initially reluctant to share data: “Sharing potentially sensitive or valuable materials knowledge with partners, and even with competitors, represents, for many, a significant conceptual hurdle.”

Aerospace

The HITEA consortium is exploring alternatives to Chromium 6+ in the aerospace industry by screening alternative systems and evaluating risks.

The value of collaboration is illustrated in the HITEA consortium, which was formed to identify alternatives to Chromium 6+ for the aerospace industry through the development of test methodologies and screening of over 160 systems for fundamental performance characteristics and legislative compliance. Granta enabled the project’s single, shared source of materials knowledge, through the use of the GRANTA MI™ software – it is used by 17 partners to capture knowledge on alternative coating systems and evaluate risks.

James explains: “In the HITEA project, by combining forces, each partner paid substantially less towards an inherently expensive and high-risk project whilst receiving the benefit of a much larger test program.”

Working with partners who push the boundaries of materials science to provide innovative solutions has made evident the importance of effectively managing project data and sharing the knowledge extracted from it.

In the Accelerated Metallurgy project, Granta’s ‘Virtual Alloy Library’ is key to the computational discovery and rapid evaluation of 25,000 unexplored alloy formulations. The geographically-distributed consortium synthesizes one alloy every 20-30 seconds, testing and characterising the alloys through a distributed partner network with significant standardisation of test methods and data representation.

James says: “In AccMet, unexpected synergies emerged. The project focussed upon the high throughput development of alloys for multiple sectors and applications with sharing of data across a consortium of 31 leading partners. By sharing the knowledge, some candidates deemed not fit for purpose for the intended user were instead identified as potential solutions for another. The willingness to share knowledge in one shared repository created opportunities that might otherwise have been missed by the project.”

GRANTA MI:Collaborate is an easily accessible package for managing materials and process data within multi-partner collaborative R&D projects.

Building on our experience in these and other projects, we launched GRANTA MI:Collaborate™ (see August’s press release) – based on GRANTA MI, it is a cost-effective, easy-to-implement software package for managing and pooling materials and process data in multi-partner projects. Access control ensures efficient, secure data sharing based on the authorization level of participants, mitigating concerns about inappropriate data sharing. Industry-proven ‘schemas’ and templates help projects to hit the ground running.

Loughborough University is a project partner in HITEA. The Department of Materials’ Prof Gary Critchlow, Professor of Surface and Interface Science, said: “I have had the opportunity to use GRANTA MI as part of two major, multi-partner collaborations. It is extremely effective at data assimilation, handling and archiving, and for dissemination activities.

“In close collaboration with Granta staff, the bespoke schemas and data importers meant large amounts of project data have been successfully recorded and compared against technical reports and other databases. This ability to rapidly inter-compare relevant data has been invaluable in terms of evaluation and interpretation and has facilitated quick, accurate report generation.”

Take a leap over the ‘conceptual hurdle’ and embrace collaboration rather than competition.

Engaging students in Eco Design through project-based teaching

Posted on November 9, 2015 by Hannah Melia

Materials educators at undergraduate level consistently raise the concern: how can we engage students in learning about materials?

Engaged students learn more and are more enjoyable to teach, and project-based teaching inspires students across engineering, design, and scientific degrees. It appeals to their sense of curiosity, integrates their knowledge and helps them to learn professional skills such as teamwork, communication, and project management.

Eco design and sustainable development form an increasingly important part of degree courses. The Eco Audit tool in CES EduPack helps students model a product and assess its environmental impact and cost during design. It is purposely not a full life-cycle assessment (LCA) tool, but something quick and easy to set up to explore scenarios. This facilitates project-based work in class. The student either downloads or builds a bill of materials for a product, detailing the composition and quantities of the components, and how the product is processed, transported and used.

Educators and students are free to analyze the model, as all of the equations used and data sources are listed in the help menu – such discussions are very welcome in this relatively new field and everyone can learn from them.

Eco data, such as embodied energy or carbon footprint of materials, is as fully referenced and accurate as possible – unlike mechanical property data, eco data is not based on thousands of physical tests – and students are advised on how to use eco data sensibly. Exercises using Eco Audit projects highlight that data with some inherent uncertainty can still be used in decision making as long as you can quantify the uncertainty.

Many projects are formed around the idea of assessing a product, suggesting redesigns, and making comparisons. Students can quickly see the pros and cons of a product change from both an environmental and cost perspective, they see which aspects of design have the greatest impact on the environment, and they can focus their efforts on making the greatest difference. At the same time, they must be aware of the cost implications and argue for their design in a business context.

A bamboo mountain bike created by Paul Eason’s students at the University of North Florida. Photo: Paul Eason

Paul Eason, of the University of North Florida, has presented conference talks on how project work using CES EduPack supports the students’ achievements of many of the learning outcomes in the US ABET Accreditation system, for example the broad education necessary to understand the impact of engineering solutions in a global, economic, environmental, and societal context. His senior capstone design students use CES EduPack for the environmental assessment of their projects, and one of most popular was to design and construct a bamboo mountain bike.

Paul says: “CES EduPack helps to promote environmental awareness and life-cycle thinking. We use it for self-directed learning and as a resource in open-ended design.”

To make smart decisions using the results from CES EduPack you need to understand the data, how accurate it is and what it can and can’t tell you. This critical thinking is encouraged through exercises and case studies.

Project-based teaching facilitates self-learning, and students explore real-life scenarios in the evolving field of eco design based on a wealth of data. Such projects help build the skills necessary to be a good engineer.

Continuous improvement through customer collaboration

Posted on July 31, 2015 by John Downing

When it comes to software development it is revolution that often grabs attention. An example here at Granta might be the recent new MI:Explore web app interface. But constant evolution is perhaps an even more important part of the story. Granta is constantly in collaboration with customers, industry consortia, and the education community with the aim of continuously improving solutions. After all, who knows better about their specific needs than the users themselves?

To understand more about this continuous improvement process, I had a chat with Dan Williams, the GRANTA MI Product Manager, about the latest enhancements to the GRANTA MI™ system (see July’s press release).

Dan is responsible for planning development work to meet, for example, the requirements of project managers at user organizations who are planning large-scale roll-outs of materials information management systems. One of their key concerns is ensuring a good user experience, so that their engineers adopt the system. In particular, they ask: “How quickly can a user get in and out to access the data they need?” Based on this input, the development team has made sure the latest enhancements halve the time to access a datasheet.

GRANTA MI 8.1 has improved performance for data access and management

Deployment is another key concern, Dan explained: “Common questions are: how can we manage users? How will we control access? How will we ensure scalability and adequate performance?”

So new tools have been added to manage ‘who sees what’ via an in-built app which, critically, was developed with week-by-week review and input from users. Organizations can control access to information according to different users’ needs, for example, materials experts, engineers, designers, procurement, etc.

GRANTA MI captures all materials data and information in one place

Each organization has specific data management requirements and many manage proprietary data alongside a library of reference data and create bespoke links to materials in Granta’s database. Updating links when new data is published could be very complicated and time-consuming, but GRANTA MI includes new tools to simplify and speed up this process. This was another problem where development had to be tested, in collaboration with customers, on real user data.

One forum for reviewing enhancements is Granta’s consortia – industry collaborations focused on materials information technology that meet regularly to review progress, share experience and guide development priorities. The latest GRANTA MI developments will be reviewed when the longest-running of these projects, the Material Data Management Consortium (MDMC), holds its 26th Meeting at GE-Aviation in Cincinnati, Ohio, next week. And the feedback from that meeting will feed the next cycle of development, driving on-going continuous improvement.

Dozens of major enterprises worldwide, operating in many sectors, already realise multi-million dollar returns by using GRANTA MI. But in maintaining these benefits and bringing them to more people, close partnership with customers is vital – the devil really is in the detail!

Teaching Materials with CES EduPack – Part One: Self-learning / Interactive Textbook

Posted on February 3, 2015 by Granta Design

In this new series of blog posts, we will be presenting a series of extracts from the white paper, ‘Teaching Materials with CES EduPack’. This week, we look at how CES EduPack can provide self-learning opportunities to enhance materials education outside of the classroom.

Self-learning

A resource than can promote self-learning can help students to work out concepts that were not fully understood in class, aid revision, or explore beyond the syllabus. To do so, it must be engaging and easy to use.

Teaching Materials Not Teaching the Software

Courses are time-constrained and so educators would like to spend as little time as possible teaching students how to use software. CES EduPack is very easy and intuitive to use. Very little time needs to be spent introducing the software. There is a set of video tutorials that show students how to use all functionalities of CES EduPack and what is in the different databases. There is also a getting started guide, with simple exercises to build knowledge of each function.

Interactive textbook

Many students bring laptops, tablets, phones, or other devices in to lectures. They might be looking up vocabulary they don’t understand in Wikipedia or busy trying to finish that homework you set. With CES EduPack on their computers, they have the possibility to put lecture content in perspective, with quick access to reliable materials property descriptions for example.

Outside of lectures, students can use CES EduPack to learn about definitions, measurement techniques, and origins of materials properties in more detail, on demand,using the science notes. These effectively act as an interactive textbook within the software. Speakers of Spanish, French, German, or Japanese can learn the English translation for materials terms in the language glossaries contained in the Help Menu. In general, the Help Menu has a lot more than just software help, for example Solutions to Standard Engineering Problems, Case Studies, Performance Index Tables, and information on Selection Methodology also being available.

All available material properties are nicely compiled in the Limit stage and their range charts, where students can immediately see the actual ranges of value for different material properties of all families, the unit used for the property and a basic one or two word description – e.g., Young’s Modulus – Stiff or Flexible (see Figure 1).

Figure 1. Science Notes and Range Charts in the Limit Stage

Explore and understand

By offering the students the ability to access CES EduPack, you can help them satisfy their natural curiosity. They can plot any of the approximately 50 properties against each other and spot trends and relationships. This is especially useful in order to prevent misconceptions, such as the difference between stiffness and strength (see figure 2).

Figure 2. Specific Stiffness vs Specific Strength

Then of course there is the data itself. In Level 1 and Level 2, the records purposely have engaging pictures that tell the student something about their use, and if possible, also show a surface finish. The descriptions and supporting information sections have a wealth of information. A student is not likely to start reading datasheets from top to bottom, but using the search function in a full text search brings up interesting answers to many questions. A search for “age-hardening” in Level 2 takes a student to the Al-alloys record, where age-hardening is described (see Figure 3). If a student has a particular application in mind, they might also be tempted to find out what something is made of by making use of the typical uses section.

Figure 3. Search for the word Aging

In Level 3, even more text-based explanations and summaries are available and searchable. Most lower-level folders have a “Folder-Level Record” which includes high level information on a group of materials (see Figure 4). This is similar to what you might get in widely used Materials Science Textbooks that have chapters on Aluminum Alloys and Carbon Steels, etc.

Figure 4. Folder-level records with information on a materials class

There is a set of resources specifically designed for self-learning available via the help menu under the case studies button. The case studies take students through the problem definition, constraints and objectives, the model, the selection, and conclusions, in such a way that the student could follow along with software.

Unappreciated materials (6): Straw

Posted on August 28, 2014 by Prof. Mike Ashby

Some materials catch headlines, are held in awe, but not all. Some get little respect, despite having changed the world. They have become commonplace, anonymous, ignored and (particularly if they are cheap) cast aside when no longer wanted. If they had feelings, they would be hurt. This brief series of blogs is to draw attention to their plight.

Rumpelstiltskin could spin straw into gold. Materials Scientists can’t do that yet. But they can do other things with straw. The value-added may be lower but the business-case has a firmer scientific base. But first: what is straw?

Straw is what’s left over when cereals are harvested. The US harvest leaves behind it 128 million tonnes of straw; globally the quantity is about 2000 million tonnes. That is about the same as the weight of steel we use in a year. The volume of straw we produced in a year exceeds that of any other material, albeit, in the case of straw, without really wanting to produce it. Straw cannot be used to feed livestock – straw is not hay – so there is an overabundance.

The perception of straw as insubstantial and worthless has evolved from fairy tales and become embedded in language. The last straw is the final, additional small burden that makes the sum of your burdens unbearable. To clutch as straws is cling to hopes that are insubstantial and have little hope of success. To set up a straw man is to advance a proposal that is easily knocked down. Straws in the wind are wisps that hint that something might happen. To make bricks without straw is to embark on a project without the proper means to achieve it.

With a reputation like that straw does not attract the research interest and funding that accrue to “modern” materials. Yet straw has many uses – straw hats, straw mats (tatamis), straw doilies, straw bedding in stables and pig-sties – but these are not going to need two billions tonnes of straw. Buildings use straw on a larger scale. Mud bricks reinforced with straw have been used as a building material since the first settlements of ancient Egypt. Adobe, with an equally long history, is a composite of clay, sand and straw. Cob, found in Europe and North America, is almost the same mixture. Both are still in use; modern versions are stabilized with additions of emulsified asphalt or Portland cement.

Straw compressed into bales can be used for load-bearing structures. It is appealing as a building material for several reasons. In areas of grain production it is inexpensive. It is an excellent thermal insulator. Its embodied energy is low and it absorbs almost its own weight of CO₂. In construction, bales of straw are stacked to form thick insulating walls, arches and vaults up to two stories high. Increasing awareness of environmental issues makes straw bale appear an attractive choice of building material.

It is not, however, one that lends itself to mass construction. The properties of straw vary with climate. The R-value of straw bale walls depends on humidity and cannot be guaranteed. It is prone to attack by insects and fungi. Erecting and finishing straw-bale housing can be slow. And the bales have to be available locally: if they are transported more than 40 miles the cost and energy required to do so exceed those of the straw itself. It is a material of niche construction.

Surely 21^st century materials science can transform this enormous resource of a natural material into something, even if it is not gold. There have been many attempts to do so: hot pressing to make binder-free straw board for packaging; injection-molding of shredded straw in a natural binder to make profiles like flower pots; extrusion of straw-reinforced plastic profiles for construction; and more. Few have been economically successful and, because processing is energy-intensive, even fewer offer overall environmental benefits. The aims are admirable but the implementation is strewn with impediments.

This makes straw seem pretty useless stuff, indeed 20^th century farmers simply burnt it to get rid of it. But earlier generations have found it useful – the evolution of housing in vast areas of the world would have been very different without it. Perhaps some 21^st century Rumpelstiltskin can find a new way to make it valuable.

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