Biomimetics and Biomimicry in Engineering

Posts Tagged ‘ultrasound’

Mathematical modelling of sonicated bubbles

In Publications on 2017/05/31 at 5:10 pm

One possible manufacturing method for bone scaffolds used in regenerative medicine involves the acoustic irradiation of a reacting polymer foam to generate a graded porosity. Sonication of foams have been our focus of research for many years now as this technology allows the porosity tailoring of cellular materials.


Sonicated foam (energy received from the left) with a marked gradation in porosity

We have joined forces with Prof Mulholland’s team (Dr Barlow and Dr Bradley) at Strathclyde University and worked on a mathematical model of a non-reacting process in order to develop theoretical confirmation of the influence of the acoustic signal on the polymer foam.

The model describes single bubble growth in a free rising, nonreacting polymer foam irradiated by an acoustic standing wave and incorporates the effects of inertia. Investigations are carried out to explore the influence of inertia on the bubble volume, fluid pressure and the stress tensors of the foam, and to explore the effect of fluid viscosity and acoustic pressure amplitude on the final bubble volume, and the curing time. A key result is that increasing the applied acoustic pressure is shown to result in a reduced steady state bubble volume, indicating that ultrasonic irradiation has the potential to produce tailored porosity profiles in cellular materials such as bioengineering scaffolds and light-weight structures.

Our work has been compiled as a paper recently published in the Journal of Non-Newtonian Fluid Mechanics and can be found here (Open Access).

We are recruiting a new member of the team

In Jobs & Vacancies on 2017/05/02 at 10:09 am

We are recruiting a Research Associate in Advanced Composites Manufacturing for the Automotive Industry.

The manufacture of lightweight composites for the Automotive Industry requires of transformative engineering and science with the academic rigour to address the challenges presented. The creation of cost-effective automotive structural components will be carried out with Sonication technologies as a new manufacturing process for multifunctional lightweight materials that exhibit bespoke mechanical properties. We are looking for an enthusiastic researcher with a background in Mechanical or Electrical Engineering and preferably with practical experience in Control and Instrumentation. We are passionate about developing our researchers so the post holder will benefit from a range of development opportunities.

The post will be based at the Multifunctional Materials Manufacturing Lab at the Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University

For more details and to apply: and the university website

Doing more with less: Bio-inspired innovations

In Comment, Publications on 2016/10/19 at 1:08 pm

The very prestigious Queen Elizabeth Prize for Engineering has invited me to contribute to their blog this month. October is dedicated to exploring the future of Manufacturing and they wanted to hear my story about the work we do in porosity tailored structures inspired by nature. It is a great honour to be showcased by them.

You can read the post here:

Or here:

The Queen Elizabeth Prize for Engineering is a £1million prize fund awarded to an engineer, or group of engineers, whose innovation has been of global benefit to humanity. Alongside awarding the prize, the QEPrize foundation also exists to celebrate and promote engineering, encouraging the next generation to take up the challenges of tomorrow.


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.


We have been in the press here and here

Economic Impact Launch – Heriot-Watt event

In Knowledge Transfer on 2012/12/10 at 2:15 pm

We gathered at the Scottish National Portrait Gallery on 4th December to celebrate Heriot-Watt’s economic impact on Scotland and the world.

Guests at the National Portrait Gallery

Guests at the National Portrait Gallery

You can see here a video that summarises a very impressive performance:

As part of the industrial collaboration and knowledge transfer activities, our Baking with Sound project was showcased by the Principal during his speech:

Showcasing the Baking with Sound project

Showcasing the Baking with Sound project

The Baking with Sound project is collaborative venture with 5 consortium members (Macphie of Glenbervie, Nortek Piezo Ltd, MONO Equipment, Fosters Bakery, and Heriot-Watt University). Its overall objective is to provide the Food Industry with an improved processing strategy to create more competitive ‘free-from’ products. It is a Technology Strategy Board funded project and it commenced in summer 2012.

The event was wonderfully organised by our 3 Communications musketeers Colin Thomson, Joe West and the incomparable Harry Loney. Great job, guys!

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)

Highlighted article in prestigious IOP collection

In Publications on 2010/05/25 at 5:09 pm

My article “Porosity tailoring mechanisms in sonicated polymeric foams”, published in September 2009 (2009 Smart Mater. Struct. 18 104001; doi: 10.1088/0964-1726/18/10/104001) has been included in the collection of highlight articles published in 2009 in Smart Materials and Structures, an IOP Journal.

The importance of engineering functionally graded cellular microstructures and the motivation behind the creation of a flexible manufacturing process are the main topics of this article.  In particular, this paper reports how the manufacture of polymeric foams with a variable porosity distribution can be achieved by ultrasound irradiation during the ‘sensitive’ stages of the polymerization reaction. The energy and mass balances were studied for each of the five distinctive stages of polymerization (i.e. cream, rising, packing, gelation and solidification) in order to determine the underlying mechanisms that ultrasound employs to affect the reaction. It was concluded that controlled ultrasonic irradiation affects convective mass transfer during foaming, especially during ‘rising’ and ‘packing’ stages, and enhances the diffusion of the blowing agent (i.e. CO2(g)) from bubble to bubble in the ‘packing’ and ‘gelation’ stages. The mechanical work put into the system by ultrasound assists both the convection and diffusion by increasing the rate of mass flux. The paper concludes with experimental results that support the above hypotheses.

These findings are of great importance for the optimisation of manufacturing processes of functionally tailored materials for ‘ad-hoc’ applications, such as biomaterials, orthopaedics, medical devices or high-tech structures (e.g. aerospace, automobile).

The full collection can be found here: of 2009

My featured article here (SmartMatStruct_09_Mechanism_porosity_tailoring_Torres-Sanchez) and here:

Post-doc job opportunity announced

In Funding, Info, Jobs & Vacancies on 2010/05/24 at 12:53 pm

My research group has advertised a new position for the EPSRC/Healthcare partnership with Blatchford and PACE. I announced the funding grant a few weeks ago in this blog. This is the original post.

We are recruiting now and the job ad can be found here

Deadline for applications is 25th June. (Interviews held on 17th August 2010)

Join us!