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Dynamics: Dropped object impacting elastic shell – 1g loading


Dynamics: Dropped object impacting elastic-plastic – 1g loading


Pressure systems: Pressure vessel under primary loading to assess local stress at nozzle to shell intersection.  Although not a particularly sophisticated analysis – ADINA is quick and efficient to set up, and can readily extract solids mid surfaces for meshing into shells.  For thick walled vessels where solid elements are required, ADINA can complete either linearization methods or non-linear analyses.


Defects, local geometry and crack like flaws.  ADINA has efficient ways to mesh geometry.  This example is used to idealise a defect.  The meshes are bonded together or glued and enable a compatible solution. This saves a significant amount of pre/post and solve time without the loss of accuracy.  Several crack like defects can be bonded into the mesh to solve fracture parameters.


In this analysis 3 load steps are used. t=1s – apply pre-load, t=2s apply internal pressure and end cap loads, t=3s apply external loads (i.e. piping loads with an increase of end load).  The pre-solved load cases are presented.


Scaled up displacement results – at t=1s bolt pre-load pushes the flange hard into contact, at t=2s internal pressure is applied – the end cap loads pulls the flange up showing partial pressure penetration developing, at t=3s external loads are applied which shows further pressure penetration.


Contact pressure between the gasket and flange– at t=1s bolt pre-load pushes the flange hard into contact, at t=2s internal pressure is applied – the end cap loads pulls the flange up showing partial pressure penetration developing, at t=3s external loads are applied which shows further pressure penetration.


Structural Systems


ADINA has several material models for dealing with elastomers and foams.  In this axis symmetric problem, simply extended to 3d, an o-ring is squeezed. It is made from Rubber.  We have experimental stress strain properties we apply, and the algorithms within ADINA do a curve fit to determine, in this case, the Ogden material properties.  Viscoelastic properties are also applied (Mullings can be applied as well).  After squeezing the o-ring, the rigid surface is lifted up – the viscoelastic properties then take time for the deformation to recover. 


ADINA has excellent coupling abilities between structural/stress models and fluid/thermal models.  In this example an enclosed volume of air is heated up which is causing a convection current, and subsequent heat transfer into the pressure vessel head.  The head is modelled as shell elements, where thermal expansion, and elasticity properties are applied.  As further heat builds up, the head further expands, but due to constraint near the head to shell interface, stresses build up.  This may be important when considering transient thermal events, such as thermal shock, or simply cyclic loading and ratcheting.  The shells could be solids, the air could be any other fluid, such as hydrocarbons.


ADINA has excellent fluid structure interaction capabilities. In this 2D example (which can be readily extended to 3D), a simple turbine is interacting with the fluid.  Pressure ramps up to a steady state, and the turbine reacts and starts to rotate to a steady state rotation.  Using this method, the fluid dynamics of a machine can be optimised, the structure can be optimised, and the interactions between both can be optimised.   


ADINA has excellent coupling abilities between structural/stress models and fluid models.  In this example, a tank is full of liquid and the base is excited sinusoidally.  It turns out the excitation frequency is at the natural frequency of the tank. This could be representative of earthquake type loadings, or periodic loadings, or arbitrary loadings such as vibrations.  This may be important in looking at bulging effects near nozzles, ship-based tanks, etc. The plot shows from left to right, the FEA/CFD model, the deformed shell von-Mises stress, and the velocity vectors of the fluid domain. 

“We required some technically challenging Mechanical Engineering to be completed to support a new R&D project. We worked with DOCAN for a period of time using ADINA. DOCAN quickly understood the requirements and were responsive and quick to deliver results. Together, we achieved a correlation between the test and simulation for a challenging mechanical system. We really liked working with DOCAN — they exceeded our expectations.”

Research ManagerSharp Laboratories of Europe Ltd.

engteq

“We recently collaborated with Rick and his team at Docan on a bespoke piece of high end Fitness for Service and Finite Element work and we were really pleased with the high level of service and professionalism provided throughout. The communication and turnaround of the deliverables was excellent and the project was delivered both on time and within budget, delivering great results for both us and our client.”

Simon Hurst – ENGTEQ Engineering Director, Part of CAN Group. July 2018

We required some urgent fluid dynamics work to be completed to prove if a new product would work.  Having worked with Rick in a past life, we contacted his team at DOCAN and gave them the challenge.  They turned around the work quickly and gave us the advice we needed.  DOCAN can be our engineering group any time.

Josh Congleton – CEO, Focus Technologies LLC.

Focus Technologies LLC

ADINA

We have used ADINA extensively for both simple linear problems, and highly non-linear problems in structural mechanics, heat transfer, fluid dynamics and fully coupled work as well.  ADINA is the basis of the Siemens NX Nastran highly non-linear implicit and explicit solvers showing the credibility this system has.  The ADINA system incorporates its own pre and post processor which is common for all the solver domains – critical for coupled physics simulations. The ADINA system has been in continuous development for decades and incorporates some of the latest numerical technology.  If you’re a NASTRAN user, ADINA can directly read in your deck, and start updating your models to account for highly non-linear physics.  We are UK distributors of ADINA.

FEMAP

At DOCAN we have used numerical methods for many years.

Many of our clients work with different solvers – FEMAP is the common link.  With FEMAP we can use clients FEA and CAD models and complete highly non-linear work via ADINA.  If the client uses NASTRAN, the benefits of ADINA can be readily used since they are compatible (ADINA being the NASTRAN Sol 601/701 solvers).  If the client requires, we can also solve directly with NX Nastran – which is coupled to FEMAP.  NASTRAN, similar to ADINA, has been in use for decades trusted by all the Space and Aero companies world wide.

SOLIDWORKS

SOLIDWORKS is our primary CAD tool.  We use this for creating all or our drawings, solid and surface models, and assemblies.  We also use SOLIDWORKS for rapid prototyping/3D printing pre-processing and reverse engineering/3D scanning data processing.

Pressure Systems Software –

CAESARII, PV Elite, Nozzle Pro and FE Tools offer a standard design and analysis route for pressure systems – for any non-standard or non-code issues we utilise ADINA

CAESARII

One of our specialist areas of work is pressure systems – we use specialist software for completing piping design, verification and fitness for service using CAESARII, and for non-standard systems we utilise FE Tools to capture non-standard SIF’s and Stiffness.  We also have experience of using Autopipe, PSA5, Peps and others – and can be used as dictated by the project requirements or the client (i.e. of class 1 nuclear).

PV Elite with Nozzle Pro

To compliment our pressure systems design and verification services, we utilise PV Elite pressure vessel software.

For the consideration of nozzle stiffness, load capacity and nozzle stresses from piping loads, we utilise Nozzle Pro which directly assesses to the ASME VIII Div 2 design by analysis method, including the ASME fatigue checks.

MATHWORKS

We use the MATLAB, Symbolic Math/MUPad, Simulink and Simscape products, with additional offerings as required.  This enables us to automate workstreams, complete system based models, and physics based systems design which is then used for FEED/Detailed design. We can also design standalone applications for clients who do not necessarily have any Mathworks products.  Mathworks is the home for technical computing.

PTC MATHCAD

We use Mathcad as a general engineering reporting tool, and engineering calculation tool.  This system is significantly better than using Excel for engineering calculations and reporting and is simple and safe to use.  The ability to incorporate units removes a massive error trap and invariably makes the final output much safer, reliable, and simpler to check. For anything which requires a significant amount of coding, numerical methods, or technical computing, we then adopt MATLAB.  Alternatively – if its just data manipulation or relatively simple work, we use Excel.

OTHER SOFTWARE

As requested, or if projects require specialist software, we also have experience of using many other codes and systems.

CONTACT US TODAY

+44(0)1606 212330 | info@docanco.com