Buffer system design gets software boost

<b>Big mobile machines often need more than just standard braking to stop them. Designing the appropriate buffer solution for such equipment is a skill set in its own right, as Tim Fryer reports.</b>

Buffers are not regular components. Machines such as cranes for use in ports, railways, steelworks or other very heavy industrial environments, are rarely standard themselves, and so the buffers they incorporate need to meet individual specifications.

One manufacturer of buffer solutions is Oleo, who claims that its buffers have the ability to absorb and dissipate 95% of impact energy, which results in a controlled deceleration of the moving machine, irrespective of speed.
However, knowing the force (the maximum end force) and the stopping distance available (stroke) is only the starting point in finding the right solution, which is why Oleo has introduced its hydraulic buffer simulation software package.

Gregory Le Brasseur, general sales manager for Oleo International explained: "We work with the OEM's who buy our buffers to use on their products such as overhead cranes and in factories, steel mills and mines. This solution is aimed at people designing products that require crash energy management. They can look at the speed their application is travelling and the moving weight, and then use the simulation to work out what product performance is required for that application to protect the people within it and the physical product."

The technology is an advancement of Oleo's existing 1D Rail Simulation software, which evaluates options for various energy absorption methods used in bolt-on devices, including couplers, buffers, anti-climbers and other crush elements for the rail industry. But cranes vary much more than trains.

"Each application is different – some cranes will travel at faster speeds than others and carry heavier weights so the buffer specifications would vary depending on the type of application and what it is used for," said Le Brasseur. "Our buffers can be customised so that any performance characteristic that the customer simulates on the website for his application can be manufactured."

Hydraulic buffers have complex non-linear performance characteristics that vary with impact speed and time, but Le Brasseur claims that Oleo is the only organisation to have developed the mathematical algorithms that accurately simulate their performance.

The new Simulation Software, allows design engineers to investigate the controlled deceleration of moving equipment, whatever the speed of impact, to define the appropriate buffer solution for any given scenario. The software takes the mass and velocity for a moving object and analyses figures for stroke, mass, and velocity to calculate the final impact force and deceleration; pointing design engineers to an appropriate buffer to absorb the impact. For design engineers working on dockside equipment in marine environments, or crane builders, the new software will provide more information and control in specifying a buffer for an application and estimating the dynamic performance of the buffer when in service.

The software allows the user to optimise the hydraulic buffers performance characteristics for their specific application and allow them to download the simulation data, buffer characteristics, installation drawings and 3D CAD model, as STP or STEp files, so that it can be incorporated within another design in third party CAD software. It can also issue a request for the manufacturing of the customised buffer solution.

"The software analyses and simulates the damping performance also giving acceleration, velocity and stroke distance/time data," added Le Brasseur referring to the role of the buffer within the overall machine. "This data can be input into user's calculations of how their particular machine is affected by the buffer."

However, it does not go as far as predicting machine maintenance schedules or determining product life according to Le Brasseur: "It is not a predicture of how many impacts over how many years before preventative maintenance is required. In that situation the users OEM equipment is usually requiring earlier repair."

Redeveloped and tailored specifically for industrial sectors and design engineers, the software is the latest technology advancement at the company, and follows the recent launch of Oleo's solution for applications requiring low energy absorption capabilities - its Type 1 range of industrial buffer.

Le Brasseur, explained how the software was developed: "Similar to our 1D Rail software, we wanted technology that was intuitive and easy to use for design engineers, which would help them find safer buffer solutions in a more accurate and automated way. Our Industrial Simulation and Configuration software complements our existing software range perfectly and will become a vital resource for design engineers working in dockside and marine environments."

These simulations are standalone, but Oleo has developed plug in modules for use with Adams Multi Body Dynamics software as well as Radioss and LsDyna Finite Element packages.

And looking to the next phase Le Brasseur added: "Our industrial software will be translated into a variety of languages to make it accessible for the multiple global markets that we serve. The next step for us is to develop our range even further to accommodate the global elevator market, which is another growing sector for us."

www.oleo.co.uk