Design for 4D printing: Modelling of smart porous networks for in-vivo deployment
Lead Research Organisation:
University of Bristol
Department Name: Aerospace Engineering
Abstract
This project has two key objectives: firstly, it aims to contribute to the 4D printing design space; with use of Abaqus and python smart composite materials can be modelled, and their subsequent shape changes simulated. This allows a user to model 4D composite materials and follow their triggered deformation over a period of time. The second objective will be to manufacture a 4D printable bio-inductive hip implant, this will be tested in various campaigns in order to optimise for use in-vivo. The aim is to use 4D materials to provide value to humans.
Osteoarthritis affects upwards of 250 million people worldwide; currently there is not a simple effective treatment that addresses the cause of the problem. Hence, one asks, can a 4D material be used to support and regenerate damaged joint interfaces? Both key objectives for the project will be carried out in unison, designed to support and optimise each other; modelling experiments should supplement physical experiments and vice versa.
Modelling in the 4D design space will be used to carry out exploratory experiments, allowing time in the laboratory to be focused and succinct. 4D material modelling will investigate the effect of hierarchical structure, i.e., can nano/micro-structures direct macroscopic shape change? This involves composite material modelling that explores micro/nano structures within a larger framework, enabling direct and intelligent shape change to provide support and growth where necessary. 4D material modelling will allow for a holistic material testing approach, many materials can be tested in a relatively short period of time. Thus, generating the most desirable material properties for supporting and stimulating a human hip joint. Following this, it will be possible to pick physical materials that closely match the most desirable material properties. In addition, multiple different material blends will be tested, producing tuneable material properties.
A stereolithographic 3D printer will be used to manufacture materials for testing, the printer utilises ultra-violet light to cure a resin instantaneously to produce a solid structure. Various printing methods will be investigated to produce the best material properties, the aim is to mimic material properties found within the body to provide the best support. Additive manufacturing produces anisotropic material properties, paired with complex loading patterns in the hip joint. It is essential that material properties are maximised in the appropriate plane. Thus, experiments will investigate how the angle of printing affects anisotropic material properties giving the optimal printing angle for implant manufacture. Furthermore, greyscale lighting techniques will be used during the cure process to produce functionally graded materials, this will mimic the joint interface that is found in a healthy human to provide further support. Modelling campaigns will supplement multi-material manufacture, in order to provide information on the most effective material blends for implant manufacture. Material testing will initially involve simple compression and shear testing outlined by standard ASTM manuals. As the project progresses, the aim will be to build a pseudo hip-joint in order to mimic the complex loading environment found within a human hip joint. In order for use in-vivo, biocompatibility must be investigated, the structure must interact in a complementary sense with the human body. Thus, experiments will be carried out to determine biocompatibility to avoid complications with implant insertion. Steps will be taken to produce a more advanced implant that stimulates joint regrowth. By incorporating bio-inks within the manufacturing process it is possible to stimulate positive regrowth, the aim will be to manufacture an implant that is bio-inductive. A bio-inductive implant will regenerate the joint interface and subsequently degrade as it is no longer needed.
Osteoarthritis affects upwards of 250 million people worldwide; currently there is not a simple effective treatment that addresses the cause of the problem. Hence, one asks, can a 4D material be used to support and regenerate damaged joint interfaces? Both key objectives for the project will be carried out in unison, designed to support and optimise each other; modelling experiments should supplement physical experiments and vice versa.
Modelling in the 4D design space will be used to carry out exploratory experiments, allowing time in the laboratory to be focused and succinct. 4D material modelling will investigate the effect of hierarchical structure, i.e., can nano/micro-structures direct macroscopic shape change? This involves composite material modelling that explores micro/nano structures within a larger framework, enabling direct and intelligent shape change to provide support and growth where necessary. 4D material modelling will allow for a holistic material testing approach, many materials can be tested in a relatively short period of time. Thus, generating the most desirable material properties for supporting and stimulating a human hip joint. Following this, it will be possible to pick physical materials that closely match the most desirable material properties. In addition, multiple different material blends will be tested, producing tuneable material properties.
A stereolithographic 3D printer will be used to manufacture materials for testing, the printer utilises ultra-violet light to cure a resin instantaneously to produce a solid structure. Various printing methods will be investigated to produce the best material properties, the aim is to mimic material properties found within the body to provide the best support. Additive manufacturing produces anisotropic material properties, paired with complex loading patterns in the hip joint. It is essential that material properties are maximised in the appropriate plane. Thus, experiments will investigate how the angle of printing affects anisotropic material properties giving the optimal printing angle for implant manufacture. Furthermore, greyscale lighting techniques will be used during the cure process to produce functionally graded materials, this will mimic the joint interface that is found in a healthy human to provide further support. Modelling campaigns will supplement multi-material manufacture, in order to provide information on the most effective material blends for implant manufacture. Material testing will initially involve simple compression and shear testing outlined by standard ASTM manuals. As the project progresses, the aim will be to build a pseudo hip-joint in order to mimic the complex loading environment found within a human hip joint. In order for use in-vivo, biocompatibility must be investigated, the structure must interact in a complementary sense with the human body. Thus, experiments will be carried out to determine biocompatibility to avoid complications with implant insertion. Steps will be taken to produce a more advanced implant that stimulates joint regrowth. By incorporating bio-inks within the manufacturing process it is possible to stimulate positive regrowth, the aim will be to manufacture an implant that is bio-inductive. A bio-inductive implant will regenerate the joint interface and subsequently degrade as it is no longer needed.
Planned Impact
There are seven principal groups of beneficiaries for our new EPSRC Centre for Doctoral Training in Composites Science, Engineering, and Manufacturing.
1. Collaborating companies and organisations, who will gain privileged access to the unique concentration of research training and skills available within the CDT, through active participation in doctoral research projects. In the Centre we will explore innovative ideas, in conjunction with industrial partners, international partners, and other associated groups (CLF, Catapults). Showcase events, such as our annual conference, will offer opportunities to a much broader spectrum of potentially collaborating companies and other organisations. The supporting companies will benefit from cross-sector learning opportunities and
- specific innovations within their sponsored project that make a significant impact on the company;
- increased collaboration with academia;
- the development of blue-skies and long-term research at a lowered risk.
2. Early-stage investors, who will gain access to commercial opportunities that have been validated through proof-of-concept, through our NCC-led technology pull-through programme.
3. Academics within Bristol, across a diverse range of disciplines, and at other universities associated with Bristol through the Manufacturing Hub, will benefit from collaborative research and exploitation opportunities in our CDT. International visits made possible by the Centre will undoubtedly lead to a wider spectrum of research training and exploitation collaborations.
4. Research students will establish their reputations as part of the CDT. Training and experiences within the Centre will increase their awareness of wider and contextually important issues, such as IP identification, commercialisation opportunities, and engagement with the public.
5. Students at the partner universities (SFI - Limerick) and other institutions, who will benefit from the collaborative training environment through the technologically relevant feedback from commercial stakeholder organisations.
6. The University of Bristol will enhance their international profile in composites. In addition to the immediate gains such as high quality academic publications and conference presentations during the course of the Centre, the University gains from the collaboration with industry that will continue long after the participants graduate. This is shown by the
a) Follow-on research activities in related areas.
b) Willingness of past graduates to:
i) Act as advocates for the CDT through our alumni association;
ii) Participate in the Advisory Board of our proposed CDT;
iii) Act as mentors to current doctoral students.
7. Citizens of the UK. We have identified key fields in composites science, engineering and manufacturing technology which are of current strategic importance to the country and will demonstrate the route by which these fields will impact our lives. Our current CDTs have shown considerable impact on industry (e.g. Rolls Royce). Our proposed centre will continue to give this benefit. We have built activities into the CDT programme to develop wider competences of the students in:
a) Communication - presentations, videos, journal paper, workshops;
b) Exploitation - business plans and exploitation routes for research;
c) Public Understanding - science ambassador, schools events, website.
1. Collaborating companies and organisations, who will gain privileged access to the unique concentration of research training and skills available within the CDT, through active participation in doctoral research projects. In the Centre we will explore innovative ideas, in conjunction with industrial partners, international partners, and other associated groups (CLF, Catapults). Showcase events, such as our annual conference, will offer opportunities to a much broader spectrum of potentially collaborating companies and other organisations. The supporting companies will benefit from cross-sector learning opportunities and
- specific innovations within their sponsored project that make a significant impact on the company;
- increased collaboration with academia;
- the development of blue-skies and long-term research at a lowered risk.
2. Early-stage investors, who will gain access to commercial opportunities that have been validated through proof-of-concept, through our NCC-led technology pull-through programme.
3. Academics within Bristol, across a diverse range of disciplines, and at other universities associated with Bristol through the Manufacturing Hub, will benefit from collaborative research and exploitation opportunities in our CDT. International visits made possible by the Centre will undoubtedly lead to a wider spectrum of research training and exploitation collaborations.
4. Research students will establish their reputations as part of the CDT. Training and experiences within the Centre will increase their awareness of wider and contextually important issues, such as IP identification, commercialisation opportunities, and engagement with the public.
5. Students at the partner universities (SFI - Limerick) and other institutions, who will benefit from the collaborative training environment through the technologically relevant feedback from commercial stakeholder organisations.
6. The University of Bristol will enhance their international profile in composites. In addition to the immediate gains such as high quality academic publications and conference presentations during the course of the Centre, the University gains from the collaboration with industry that will continue long after the participants graduate. This is shown by the
a) Follow-on research activities in related areas.
b) Willingness of past graduates to:
i) Act as advocates for the CDT through our alumni association;
ii) Participate in the Advisory Board of our proposed CDT;
iii) Act as mentors to current doctoral students.
7. Citizens of the UK. We have identified key fields in composites science, engineering and manufacturing technology which are of current strategic importance to the country and will demonstrate the route by which these fields will impact our lives. Our current CDTs have shown considerable impact on industry (e.g. Rolls Royce). Our proposed centre will continue to give this benefit. We have built activities into the CDT programme to develop wider competences of the students in:
a) Communication - presentations, videos, journal paper, workshops;
b) Exploitation - business plans and exploitation routes for research;
c) Public Understanding - science ambassador, schools events, website.
