Sophie Cox, a doctoral researcher at WMG based in the materials and manufacturing theme group recently undertook an internship with Ceram, an independent materials technology company. Sophie joined Ceram’s biomaterials innovation team to further her commercial understanding of the synthesis and testing of medical materials, specifically hydroxyapatite (HA).HA is a popular bone replacement material because it is chemically and crystallographically similar to native bone mineral. It is used in a number of clinical applications, including inert implant coatings, void or defect fillers, bone grafts, hard tissue scaffolds and drug delivery entities. Control of chemical (e.g. crystallinity) and physical (e.g. particle size) characteristics of HA is important as such properties ultimately define in-service performance e.g. bioactivity and mechanical strengthDuring the internship Sophie investigated and compared a range of common HA synthesis methods according to a pre-defined set of criteria that culminated with a white paper published on Ceram’s website. Furthermore, utilising Ceram’s state-of-the-art reaction vessel Sophie was able to produce HA under a range of controlled conditions to further understand the influence of these parameters on the characteristic properties of the resultant product. Further investigation is being completed at WMG as part of Sophie’s doctoral thesis.In addition to the synthesis of HA, Sophie also investigated the potential to improve a standardised testing procedure during her time at Ceram. Vigorous regulatory tests are employed in the medical device industry, which are generally very expensive and time consuming. In contrast, ISO23317:2007 ‘implants for surgery – in vitro evaluation for apatite forming ability of implant materials’ offers a relatively quick and cheap assessment of material bioactivity. However, the procedure (an examination of new HA deposition following sample immersion in simulated body fluid) does not enable the bioactivity of different samples to be quantitatively distinguished. To assess the feasibility of using advanced x-ray diffraction analysis to quantify HA deposition, Bioglass disc samples were immersed in simulated body fluid in accordance to ISO23317:2007 for up to 28 days. The experimental results collected by Sophie are currently being analysed at Ceram and are planned to be presented in a scientific paper.
Research undertaken with Oleo http://www.oleo.co.uk/
Railway vehicles traditionally use hydraulic mechanisms to absorb kinetic energy in day to day operations, such as shunting or general train operation. Hydraulic buffers can absorb a large amount of energy in a fully reversible manner. For more severe impacts it may not be possible to install hydraulic buffers with sufficient stroke to absorb the required energy, due to their relatively long installation length. Other devices need to be added to the vehicle crash energy management system to cope with the increased energy absorption requirements and to ensure the crash energy is absorbed in a controlled manner. The energy absorbing devices also need to keep adjacent vehicles aligned and resist vehicles overriding.
BS EN 15227 requires that railway vehicles need to be able to absorb the energy of a crash that occurs at speeds up to 36 km/h. Given the large mass of current railway vehicles, this requirement equates to a need to absorb approximately 1000kJ. This is roughly 20 times more severe than a typical car crash.
This project is focused on developing the most efficient energy absorption mechanism for railway vehicles. The objective is to develop an innovative stand-alone energy absorber, which has a good ratio of deforming stroke to installation length and is resistant to vehicle loads. To complying with the requirements of the BS EN 15227 standard it will be necessary to demonstrate that the performance of the device is predictable and can be simulated.
Initial work used a decision matrix approach to compare various energy absorbing mechanisms and assess their suitability to railway applications subject to BS EN 15227. It was determined that energy absorption by radial expansion is the most efficient method but due to the non-collapsible nature of expansion tubes, a combination of expansion tube and other collapsible energy absorption mechanisms is being investigated in detail for use as a buffer.
The researcher has simulated the performance of the proposed hybrid mechanism using finite element analysis and scale models have been tested. This work has demonstrated the working principles, quantified the benefits over conventional energy absorbers and illustrated the potential application of conventional composite materials to railway energy absorbers.
The research work has produced a simulation model of a compact energy absorber and has verified the stability of the mechanism under transverse loading. Testing of prototypes is expected to be completed by early 2014.
The simulation images below show an expansion tube (non-collapsible), a splitting tube (collapsible) and the proposed hybrid solution.
Objective: To significantly reduce the weight of an electric go kart while maintaining functionality and robustness
- Identify key components which can be light-weighted
- Identify alternative materials and assembly options
- Model components in new materials to evaluate weight reductions and predicted functional performance
- Prototype weight-reduced components and verify functionality
- 10 components identified as offering significant weight reductions e.g. nerf bars, stub axles, rear axle, roll cage, bumpers
- Alternatives to steel and aluminium evaluated e.g. magnesium, titanium, maraging steel, tritek polypropylene composite
- Overall weight reduced by 20% while maintaining structural integrity and improving crash worthiness
- Weight distribution optimised front-to-rear and left-to-right
This project was carried out by 4th Year Engineering Undergraduates applying the light-weighting concepts and research outcomes from WMG centre HVM Catapult
The Lightweight Technologies team at WMG recently worked with GRM Consulting Ltd to investigate ways to significantly reduce the weight of a car seat as well as reducing the environmental impact of manufacturing the seat.
WMG’s approach was to characterise possible new candidate materials and then evaluate them against benchmark materials. The predicted performance was simulated using finite element analysis which enabled performance to be optimised.
Selected new materials were then used to build a prototype seat and performance was verified against the predicted performance.
Prototype parts were manufactured at WMG and an optimised thermoplastic composite seat design was achieved. The lightweight composite solution passed all selected US Federal test standards. The project proved that up to 50% weight reduction is achievable and the overall environmental impact was significantly reduced.
The research team has now moved on to develop a rapid stamp-forming process to create a high-performance thermoplastic laminate solution with a target cycle time of less than 90 seconds (equivalent to 50,000+ parts per annum). This will be a fully recyclable, advanced composite, light-weighting technology.
Optimising and Validating on-CMM Laser Scanning Technologies for Automotive Applications
The WMG Product Evaluation Technologies Group, in collaboration with Nikon Metrology and Jaguar Land Rover, are investigating the optimisation of laser scanning technologies for production measurement systems in automotive applications. Click Here to read the full project summary.
This project aimed to assess the feasibility of manufacturing a race wheel from carbon fibre. Typical wheel materials are steel, aluminium and magnesium. Carbon composites offer potential weight savings of 60 % compared to these materials. Carbon fibre’s high specific properties, high environmental resistance and excellent fatigue resistance make it an ideal material to reduce the mass of vehicle components, thereby reducing vehicle emissions.
The objective of this project was to design, optimise and manufacture a lightweight 13” x 6” carbon fibre racing wheel rim for use on a Caterham sports car. To ensure the wheel was as robust as possible, the worst case design parameters were chosen from the range of Caterham’s available which accept a 13” x 6” wheel rim (Academy, Supersport and R500 Superlight models). The wheel had a two-piece split rim design.
Catia V5 was used to design the wheel as a surface model. A surface mesh was then exported into the composite optimisation software, Genesis. Optimisation of the wheel was conducted in Genesis by subjecting the rim to a cornering force, torque, centripetal force and tyre pressure calculated from the design parameters. The optimisation took account of the carbon fibre properties, number of plies in the layup and ply orientation. Topological and stress-strain finite element analysis results were used to guide the development of the wheel geometry. The images to the right show the development from version 1 to version 6 of the wheel design.
Laminate Tools software was used to model the draping of carbon fibre onto the moulds. It identifies areas of high shear strain in the woven carbon fibre that will prevent it from draping correctly. The layup can then be changed to incorporate darts or multiple smaller plies. The draped parts then underwent a vacuum bagging process to cure the carbon fibre. The resultant front and rear rims were bonded together with a one part epoxy to create the assembled wheel rim.
This project demonstrated the use of modelling and optimisation software in the successful design and development of a complex structural carbon fibre component. The manufactured wheel rim weighed 1.2 kg, a mass reduction of 76% in comparison to an equivalent forged aluminium race wheel. This weight saving is a result of the use of carbon fibre and the implementation of composite orientated optimisation software.
Validation Testing of ALM Intake Valves
Two hollow engine intake valves have been produced using ALM (EOS M270) in Inconel 718, sealed using laser welding, and ground to a finished state by conventional processes. The valve design enabled by this manufacturing route represents a minimum 20% weight saving if a conservative approach towards maximum fatigue stress is adopted. Greater savings may be possible with further optimisation. Please click here for the full report