
Blog
SPH Ball Bounce
I’ve put some of my ball bouncing on water stuff on here before. I’ve been playing with these models for over 10 years, and initially I tried to do it with SPH. Didn’t have much success in the early days with it and switched to CEL, but as I’m writing an online intro to SPH for NAFEMS I thought I’d try again. The results I’ve achieved using DualSPHysics are pretty good I think. There’s a big temptation to actually try to validate this…

Space Mouse Hardware review
20th September 2024
Hardware reviews are something new for me. But its easy to review something that you really rate and couldn’t work without. In all honesty the review was a bit of a joint effort between me and Mr Holmes. Not sure about the line about cutting off fingers though.

Topology Optimisation at last..
20th August 2024
For a while I’ve been wishing that somebody would release a free topology optimiser. Well they’ve done it. A group at the University of Alberta have released OPTIWORKS, and a few other goodies to do with lattices, and it really does look like it works. I’m certainly going to be using it. I’ll put a link on the resources page.

Getting to grips with PrePoMax
19th July 2024
I’ve just completed a small project for a customer, and used PrePoMax and Calculix. As with all new FEA codes/systems it takes a bit of getting used to, but it proved easy to use, and above all accurate. Hopefully before long I’ll be able to post some info on the project.

Latest in Develop3D
14th June 2024
The end of term at Brookes means that new content on here has been a bit sparse. But here’s my latest from Develop3D.

Travels in Hyperelasticity Part 3
5th March 2024
Well Marks enterprises made the significant investment in a set of those slotted weights that you find in school science labs. And the results were transformative in terms of material characterisation. I’m never going to be competing with RAPRA, but the ability to characterise a hyperelastic material from beginning to end has been in incredibly useful in improving my understanding, from basics to nuances. As our marketing department at SSA used to say “every day is a school day”. And that makes for decent training material.

Training Course Example
19th February 2024
Keeping training course notes up to date and relevent is one of those never ending works in progress. So this kart disc carrier that I was asked to re-engineer is very welcome. It makes a superb example of how not to create parts with sharp corners, has an interesting loadcase that causes the failure (which I only found out about after drawing it – it has to be hammered on to the axle), and can be extended to include bolts and even X-Fem.

Nafems Explicit Course – goes live!!!
2nd February 2024
At last the course I wrote for NAFEMS, “Getting started with Explicit FEA” is up and live on their website. This couse was a lot of work, but I learned a lot putting it together and I’m really proud of it!!

Nafems Explicit Course – done..
28th December 2023
I’ve been writing a course that is basically an introduction to explicit solvers for a while now. It’s for NAFEMS. Today I completed, and delivered, the last item on the list. I don’t know about anyone else, but I learned a lot putting this together. More details on my training courses page.

Retro CAD Modelling
15th December 2023
I do quite a lot of CAD modelling for a range of customers. Most of which I’m not allowed to show. But this small project doesn’t have much in the way of design IP and I think it looks quite cool. So I’m posting here.

SPH for Solid Mechanics
12th December 2023
In a conversation with work friends the subject of modelling damage and failure in solids using SPH came up. It was that sort of conversation. I was pretty sure I’d done it before, but then couldn’t find any evidence that I had. So as usual I needed to make a test model. Which works surprisingly well.

More on Explicits in Develop3D
19th November 2023
More on explicit solvers, and even a reference to the course I’ve written for Nafems. Readable version on the D3D website.

More FSI using Abaqus CEL
4th October 2023
The skipping ball problem is one I keep returning to. This time I thought it would be a good idea to investigate the adaptive options and how different mesh refinement options influence the results. As this project refuses to be anything other than a work in progress (it’ll never cause an invoice to be generated so why should it ever finish?) it’ll be no surprise to anyone that there are still many more questions than answers. My latest set of notes on this are downloadable from my resources page.

Travels in Hyperelasticity Part 2
18th August 2023
The machine to generate uniaxial test data for hyperelastic material models has now been completed. And it works! Now I need to crack on and generate some material data, and then the training material/videos.

CFD project
3rd August 2023
I’ve recently completed a project looking at the internal flow in an electronics enclosure. Can’t go into details on what it is and why we did the work, but I am allowed to show some plots of what I did. All CAD modelling was carried out using SolidEdge, CFD pre processing was done using FreeCAD and it’s Openfoam workbench. Solutions were run using Openfoam and post processing done in Paraview. (I’ve changed the PPT text to symbol to hide the details).

In this project I managed to improve my knowledge of how FC/OF can be used (there’s a lot of hacking around with scripts in a very 1990’s manner), and how the data can be managed. It does look like it can be made a pretty effective tool in the right workflows. (I’d still prefer to be doing this stuff using CCM+. but needs must etc.)
Travels in Hyperelasticity
30th June 2023
I’m not currently awash with fee paying work. So it’s an ideal opportunity to increase and improve my understanding of material models. I wondered how far you could go with material characterisation using only rigs and machines you’d built yourself. I’m currently at the “lash something together” stage, which has been more successful than I’d ever have imagined. Now I’m designing (and buying the parts for) an proper rig. Watch this space. When I’ve got something useful together I’ll start uploading models and presentations to the resources section of this website.

Latest in Develop3D
15th June 2023
Possibly slightly unfairly, I have a pop at all the pointless simulations on the internet.

More explicit examples
8th June 2023
I needed to illustrate some slides about applications of explicit codes. One really early example was ESI modelling an aeroplane flying into a nuclear power plant. The results don’t seem to be in the public domain so I had to do my own illustration. The geometry is of a Keil Kraft Cub, downloaded from grabcad.

Explicit solver training examples
18th May 2023
I’ve been working on some explicit solver training examples. One of which I really quite like.

CMBBE Conference, Paris, May 2023
7th May 2023
Last week I went to Paris to present some ideas on efficient strategies for implant component optimisation. The CMBBE conference was superb, with presentations on subjects ranging from modelling tumours to football injuries at PSG, and a poster on modelling greyhounds racing. Colleagues Olga Barrera and Xiaoyi Min also presented their work. I’ve added a pdf of my presentation to the resources page.

SPH/CEL/DEM training
28th February 2023
Recently I’ve been putting some training material together on SPH, CEL and DEM for my old employer Technia.

Latest Develop 3D Article
20th February 2023
I’ve actually written something about digital twins in the current Develop3D magazine.

Benchmark article
19th January 2023
Its been a while since I had anything in Benchmark. So I’m really very pleased with this.

More FEA Introduction Training Notes
30th December 2022
In the break between Christmas and the New Year I’ve been working on the training notes some more. They are going to emphasise the importance of validation and living in the real world more than previously. I’m quite pleased with the first example, so I’m posting it here.

Hopefully I’ll get the opportunity to start giving this course in 2023.
FEA Introduction Training Notes
18th December 2022
When we sold SSA we sold all the training material I had created. So now I’m having to create new notes for the training that I’m doing. One interesting thing is that I’ll now be able to use a range of solutions obtained with different software products in them, which is certainly different to what I’ve done in the past. I’m also writing a course on explicit solutions for Nafems, and one on CEL/SPH for Technia.

Villiers Ignition Spanner Project
12th November 2022
Sometimes its great to get your teeth into a simple project. I was asked if I could make a spanner for the ignition on a DOT scrambler – it uses the near ubiquitous Villiers 2 stroke engine. Obviously I could, but I thought it would be a great opportunity to 1.do it properly and 2.use all the technology at my disposal. So the project was centred around a 3D CAD model, used a 3D printed prototype, and laser cut steel components. For somebody who has spent most of his career in simulation, trying out different press fits and hanging off them physically to test how strong they are was something of a departure.

Work on Formula Ford Engine
8th October 2022
I’ve been working on a basic model of a Ford 1600 Kent engine, as used in Formula Ford 1600, for obvious reasons.
Presentation at Abaqus RUM 2022
15th September 2022
It was great to be back at the Abaqus RUM, held in Manchester. I presented a paper on the knee work I’ve been doing with Olga Barrera and Rosti Readioff.

Multi-scale Article in Develop3D
31st May 2022
I’m quite pleased how well recieved this has been.

SPH using DualSPhysics
17th May 2022
FreeCAD seems to be turning into a useful front end for a number of simulation codes. I’ve used the FC front end for Openfoam for a while now, but a recent enquiry about free surface flows prompted me to look at the DualSPhysics FC implementation.
In short its a great piece of code. Didn’t take too much effort to learn from the online video tutorials. And because it’s inside FC and uses Paraview for post processing the amount I needed to learn was minimised. But I guess the most astounding thing is that in the process of making 4 or 5 models to learn the basics of the code I didn’t manage to make it crash once.

Now I’ve got a really decent SPH code and can use it. I guess all I need now is a project to use it on.