Biomimetics and Biomimicry in Engineering

Posts Tagged ‘porous materials’

Manufacturing Functionality: from SFF to truly SFF

In Seminars and Keynotes on 2016/04/05 at 8:13 pm

Solid Free Form (SFF) fabrication, also known as Rapid prototyping (RP) or Layered Manufacturing (LM), creates arbitrary 3D shapes directly from Computer-Aided Design (CAD) data. It has been around for two decades now. From its early age it demonstrated tremendous advantages for the Computer-Aided Manufacturing (CAM) industry compared to traditional manufacturing methods such as CNC machining or casting. The venues for exploration appeared endless until users started to hit a ceiling; the name ‘rapid’ became almost ironic because the layering process is a very slow one, the palette of materials to handle is limited and the advertised label ‘net-shape’ is ‘near-shape’ – on a lucky day-. We are now over the hype of SFF, RP and LM but still have needs to create heterogeneous structures that have intrinsic multifunctionality. The Multifunctional Materials Manufacturing Lab in Loughborough University works on new manufacturing methods that allows a truly free form fabrication and the engineering of composition and structure for the creation of materials that are smart, responsive to their environment and possess synergistic properties that enhance their behaviour. These types of high performance materials offer great promise in fields such as bioengineering and transport (i.e. automotive and aerospace).

Venue: Department of Physics, Universitá degli Studi di Milano, Aula Consiglio. Italy

20160405_UnivdegliStudidiMilano

Lightweighting

In Funding on 2016/02/24 at 2:58 am

Lightweight materials are the next pit-stop in the challenge of reducing mass, curbing emissions and improving fuel economy in the low carbon vehicles of tomorrow.

UK’s ambitious commitment to decarbonisation of the transport industry by 2050 is going to require a creative approach. Current reductions have been gained by improvements in engine performance but these gains are diminishing. If we were to go 100% electric, we still need to produce the electricity, so the footprint is not necessarily diminished as much as it could appear. To meet the carbon emissions target we need to reduce vehicle mass. For example, a car the size of a Ford Focus would need to reduce mass by about 300kg (from ~1200kg to ~900kg).  The car industry needs to find a way to manufacture lightweights without adding production cost in the shorter term.

Loughborough University and Far UK Ltd, a Nottingham-based innovative low-volume tailored vehicle designer and manufacturer, have joined forces to explore the concept of novel and engineered structures, multifunctional materials bespoke for their mechanical properties, and manufactured in a cost-benefit and continuous fashion using Sonication technology that allows on-demand tailoring of porosity. This exciting research program has just secured co-funding from the UK’s innovation agency, Innovate UK.

This programme of research presents a new avenue for high value manufacturing and helps support the UK knowledge base, economy and jobs.

TSB_announcement

We have been in the press here and here

Is DIY a western thing?

In Info on 2015/09/11 at 6:18 pm

Changxi Huang has been working on the bamboo hut project as part of his MSc project. His work has focused on the optimisation of the procedure for assembling the hut and looking for ways of best presenting the assembly instructions to those who can’t read instructions or have no previous knowledge on building huts.

He ran experiments with participants from different walks of life and, most importantly, from western and far east countries. One of the main points of discussion of his dissertation is based on his observations on the approach that western nationals have towards do-it-yourself products versus that of Far East countries citizens. In countries like China, assembling a product (a table or a chest of drawers) is left to those who perform that job for a living. On the contrary, the B&Q-isation or the IKEA-ising of western countries has made our exposure to self-assembly furniture and products an activity of our everyday life. Could this have an effect on our cognitive ability to understand instructions and our dexterity to carry out such assemblies?

Huang observing one of the tests in our study

Huang observing one of the tests in our study

Huang has successfully finished his MSc course and is going back to China for a most deserved rest. Well done, Huang!

MSc exhibition on 9th Sept (Loughborough University) and Farewell (or a ‘see you soon’):

Huang_exhibition_farewell

The Future Engineer podcast engineer

In Seminars and Keynotes on 2015/02/10 at 11:23 am

STEM XX 016 episode is on the importance of multidisciplinary engineering, the power of positive thinking and biomimetics – learning from nature to solve our technical problems.

If you have ~30min to spare, have a listen and please leave comments below and tell me what you think. Thanks!

You can listen to it here and download it here.

Mathematical Modelling of the use of Ultrasound to Tailor Polymers

In Info, Seminars and Keynotes on 2015/01/27 at 12:13 pm

Materials whose internal porosity can be tailored during the manufacturing process could be of use in a wide range of applications such as bone scaffolds (to help new bone grow from stem cells).  A recent method for achieving such a manufacturing process involves the acoustic irradiation of a reacting polymer foam which then results in a final sample with a graded porosity.  This talk will present the first mathematical model of this process. The polymerisation process is complex involving, for example, bubble dynamics, evolving rheology, two phases, reaction kinetics, and gas diffusion.  In addition, the model has to include the effects of the irradiating ultrasound.  The model I will present treats the evolving fluid as a multimode Oldroyd B system and will focus on a single moving bubble boundary using a Lagrangian frame of reference.  After looking at the role that inertia has on the dynamics of the system, a multi-bubble model is constructed that generates a heterogeneous bubble size distribution shaped by the ultrasonic standing wave pattern.

My colleague Dr Tony Mulholland, from the Department of Mathematics and Statistics, University of Strathclyde, will present this remarkable piece of work on the 27th January 2015 at 1pm in venue: S.1.73 (Materials Department, Loughborough University). Join us if you can.

Making sense of standardisation

In Publications on 2013/11/18 at 12:27 am

Standardisation is that useful process that allows us engineers to share a common ‘plane of reference’ on which to base our conversations. It is useful to know that a material (say, a slab of titanium) has the same mechanical properties when it is measured in Loughborough, Sydney, Lima or Granada.

But sometimes standardisation goes too far on the other extreme. The over-translation from observation to technical definitions might turn an ISO norm into a document that is no longer useful for practical purposes. This is particularly risky when ISO norms attempt to tabulate and measure in ‘softer’ areas such as healthcare and rehabilitation.

In a piece of work recently published here, my colleagues from the NHS Scotland SMART Centre and we have restated some practical insight to an ISO norm that guides the characterisation of wheelchair cushions for a better guidance to prescription by clinicians.

Our work has been well received by the practising community and we look forward to continue working with them.

Ref: Hollington J., Hillman S.J., Torres-Sanchez C., Boeckx J., Crossan N., “ISO 16840-2:2007 load deflection and hysteresis measurements for a sample of wheelchair seating cushions”, Medical Engineering & Physics, in press. DOI:10.1016/j.medengphy.2013.10.010 

Learning from natural ‘sandwich’ structures

In Info on 2013/07/16 at 10:28 am
porcupine quill

porcupine quill

The porcupine quill is a quite interesting material. A pretty large shear modulus, flexible in 3-pt bending tests, but very stiff in the longitudinal direction, which serves well as a defensive weapon.

It is surprisingly lightweight, so the first thought is for a sandwich structure of different materials, but what type of structure?

The photos below show images of a longitudinal slice of a quill under the optical microscope. As expected, a soft core (cellular-foam like) and a denser ‘skin’.

Optical micrsocope images: transversal section and several magnifications

Optical microscope images: transverse section and longitudinal at several magnifications

As it commonly happens, the interesting story starts when you get to see beyond what the human eye can. At higher magnifications, the ‘skin’ shows a complex structure, with layers of material oriented so they form another ‘skin’ structure within the ‘skin’ itself, with a core oriented vertically (in these photos) and the skin running horizontally. (The big black vertical scars could be scratches at the time of polishing, though)

Transverse sections at different magnifications

Transverse sections at different magnifications

This multiscale ‘skin’ is a good solution for providing stiff properties but not at the expense of heavy, dense materials.

Special thanks to Andy Sandaver, who recently retired from the Wolfson School and we already miss his exceptional technical skills. And my gratitude to Edinburgh Zoo, where the samples were collected.

Baking with Sound

In Knowledge Transfer on 2011/10/11 at 2:52 pm

A collaborative project between Macphie of Glenverbie, food ingredients suppliers and manufacturers, and my research group has been highlighted by the Scottish Food and Drink Federation.
This research project has a remarkable character of knowledge transfer and is the founding stone for a larger implementation project in which the bakery industry will benefit thanks to our novel strategy to control and tailor structures.

 
This project was also showcased in their last Parliamentary reception (Scottish Parliament, Sept 2011). Richard Lochhead MSP, Cabinet Secretary for Rural Affairs and the Environment, underlined in his keynote speech the importance of innovation and the benefits of partnerships in academia and industry. More on this day can be seen here, page 8.

Heriot-Watt and Macphie have a record of successful collaboration in different projects at both Undergraduate and Postgraduate level.

Ashley Baker, Head of R&D at Macphie with Carmen Torres-Sánchez, from Heriot Watt University

International Journal of Design Engineering – Special issue on ‘Design in Nature’

In Publications on 2011/07/25 at 10:25 am

The International Journal of Design Engineering (IJDE) has just published its Special Issue on Design in Nature.

I am very honoured to have my work included there. For this special occasion, i wanted to show-case the developments on a novel manufacturing method for cellular materials with a graded porosity distribution.

The motivation for creating a gradient of porosity in materials has been inspired by nature and aspires to mimic natural structures so their intrinsic advantages (e.g., optimised mechanical properties) can be exploited. Many engineering applications (e.g., thermal, acoustics, mechanical, structural and tissue engineering) require porosity tailored structures. However, current manufacturing processes are currently unable to mass-produce these foams. In this work, low power-low frequency ultrasonic irradiation has been used to excite polymeric foaming melts that, once solidified, contained different porosity distributions throughout in their solid matrix. This was possible by controlling the amount of energy imposed on the samples. The generation of porosity gradients that resembles those of natural cellular structures (e.g., bones, stems) opens up new opportunities in the design and manufacture of bio-inspired materials that can solve challenging technological problems.

Torres-Sanchez, C. et al. (2011) ‘A novel manufacturing strategy for bio-inspired cellular structures’, Int. J. Design Engineering, Vol. 4, No. 1, pp.5–22. DOI:  10.1504/IJDE.2011.041406. A copy can be found here and here.

Making shapes and tailoring properties with ultrasound: the biomimicry approach

In Info, Seminars and Keynotes on 2011/05/11 at 8:40 am

If we want to mimic nature in order to improve ourselves and our built environment, then perhaps we should think about what’s important in
the biological world.  Shape, form and functionality are features that nature optimises, rather than maximises.  Form generally takes the path of least energy and material, and functionality is not understood without a multifaceted aim.

New trends in the design and manufacture of orthopaedic implants and scaffolds are moving towards the fabrication of functionally designed
specimens.  These not only offer a network for the cells to grow and proliferate, but also an environment in which this process can be accelerated (e.g. tailored chemistry for the cavities’ walls, and porosity gradation to lessen clogging and isolation of the cells that are situated at the very centre of the scaffold).  This new strategy for the generation of geometries and chemical environments is aligned with the biomimetic approach of manufacturing.  The final specimen is made to both look like and behave like natural muscle, cartilage, and bone tissues.

Ultrasound is used to control, manipulate and destroy bubbles.  In our work, ultrasound is used to ‘create’ bubbles.  In a polymeric melt
undergoing foaming, ultrasound can be directed to the matrix that surrounds the bubbles and enhance mass transport, diffusion and heat
flow.   In this way, shapes and forms, and functionality can be tailored.  It is the interrelationship of the cavity shape and the polymeric melt properties what the ultrasound can engineer.

Using this sonication technique, porosity graded materials are manufactured to match the requirements of biological substrates for
bioengineering applications.   We have successfully manufactured sonicated scaffolds that show a higher viability for hosting cells and
enhance their proliferation.  This opens a route for the individualisation (‘mass customisation’) of more efficient structures that potentially can be used as orthopaedic implants, and help alleviate the growing needs of an ageing society.

When: Wednesday 11th May at 1.15pm

Where:  JM F.48 (School of Life Sciences, Heriot-Watt University), Riccarton Campus)