Simulation of Dynamic Fluid Power Systems

The simulation of pneumatic and hydraulic systems helps improve your understanding of complex relationships and interactions within the system and raises your awareness of existing optimization potentials.

Simulation and modeling of fluid power components and systems

Fluid power drives and controls can be found across all industries. Whether they are used to transport liquids or gases, or to transmit power: minimum pressure losses and vibrations in the overall system along with efficient fluid transport are often decisive factors for the competitiveness of the final product. Due to the non-linear properties of fluid power systems, spreadsheet-based design approaches have their limits. In order to increase performance and efficiency of fluid power systems, you look at the fluid circuit, its controller layout and the connected mechanical as well as electrical components as a whole for the best results. The most effective way to do so is to use software for simulating your fluid power systems.

The task at hand

Hydraulics simulation as part of system simulation

There was a time when controlled electromechanical drives seemed to replace hydraulic systems almost entirely even in their classical field, mechanical engineering and plant construction, but meanwhile, they are back and well established in many industries thanks to their affordable, smart and highly dynamic actuation axes. Advanced digital control engineering and elaborate valve systems achieve unprecedented quality levels in terms of functionality, reliability and precision. Power peaks can be attenuated by hydraulic accumulators which allow for significant cuts in the plant’s energy consumption. For first-class results, the hydraulic lines, accumulators, valves and actuators are not considered separately, but as a global system including closed-loop controls as well as electrical and pneumatic auxiliary components. System simulation is a well-established tool for incorporating the advantages of hydraulic and electrohydraulic drives into competitive products.

The solution

Safe and efficient pneumatic systems in automotive engineering

Air springs, air brakes, exhaust gas after-treatment, pneumatic control lines and actuators in transmissions: pneumatic systems play a key role especially in commercial vehicles. Pneumatic simulation is an excellent way to find early answers to a number of questions already in the design phase or during the system test. For example:

  • Can the required pressure be provided in any situation?
  • How long will it take to build up the required pressure and how fast are the transmission paths?
  • Is the pneumatic system subject to unfavorable pressure fluctuations?
  • What configuration is best for optimal performance with low energy consumption?
  • How to dimension compressors and accumulators?

Pneumatic simulation for energy-efficient air supply and air conditioning

Air conditioning systems use lower pressures than typical pneumatic applications. Physical correlations are, however, similar. Due to pressure drops, branched systems and the challenge to come up with low-energy low-cost plant designs, the following questions are crucial to product development.

  • How should the system be designed to provide the required air volume at each of the air outlets?
  • What is the optimal configuration of cross sections and orifices?
  • Which air flow can be delivered to which outlet? A simulation model allows you to find the best suited configuration in the conceptual phase already.

Simulate fluid power systems and discover the potential of accumulators

Under development for drivelines in motor vehicles – already standard as auxiliary drives in certain heavy-duty machinery: air and hydraulic hybrids. Pneumatic or hydropneumatic accumulators collect recuperated energy and transmit it to the drive system as needed or during peak loads. Fluidic accumulators play a key role in reducing fuel needs, emissions and electric energy consumptions of machines. Covering peak loads with stored energy from a fluid accumulator makes it possible to design a smaller engine and run it at an optimal operating point. Compressed-air accumulators can also be used for storing energy from solar or wind power plants.

The design of hybrid fluid power drives and pneumatic accumulators requires the following questions to be answered:

  • What is the entire system’s efficiency?
  • How much energy can I store or save at which investment volume?
  • What are the optimum accumulator dimensions?
  • How long does it take to store or release a certain amount of energy?
  • What is the loss rate?

These questions need to be answered although there may be almost no previous experience to rely on. A simulation model enables you to try and test many alternative configurations and technologies based on various realistic application scenarios, which gives you a solid basis for making the right decisions.

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The benefits

Optimal design for hydraulic drive systems in mobile work machines

Whether in mining, agricultural or construction machinery – hydraulic travel and work drives are widely used due to their high power density and flexibility. Efficiency of the hydraulic system is crucial to economical operation and compliance with statutory and regulatory requirements. Simulation will assist you in the optimal selection and dimensioning of the accumulator and in hydraulic transmission designs adjusted to the driving cycle in work operations. Besides the optimal design of control and pressure lines for work drives, valve selection as well as pump and cylinder design, but also stable controls are vital. System simulation helps you keep it all manageable and find the optimum balance.

Fast and economical handling of workpieces through pneumatic simulation

In automation technology, pneumatic actuators realize high processing speeds. At the same time, pneumatic systems are very economical and robust low-weight solutions. They are frequently used for loading/unloading and positioning of workpieces. For best results, it is crucial to find the perfect combination between electrical controls, pneumatic actuators and mechanical components. The objective is to realize inexpensive high-speed high-precision systems with high energy efficiency. Any modifications to custom-made products or small production series after construction would incur significant costs. Virtual commissioning of the machines allows you to run reliable functional tests before the machine is even built and to make constructional changes at any stage.

Practical examples
  • Moog

    Moog’s engineers use simulation to for quick and reliable assessments of the static and dynamic behavior of their systems. Read on to find out more.

    about Moog's project
  • Liebherr

    Liebherr evaluates and optimizes the vibration comfort of their wheel loaders through virtual prototypes, which reduces testing efforts significantly. Read on to find out more.

    about Liebherr's project
  • Daimler Trucks

    Daimler Trucks develop pneumatic braking systems by means of dynamic simulation. Virtual testing of brakes enables them to reduce iterations in the trial phase already. Cost and time-consuming revisions to production vehicles or prototypes are thus things of the past.

    about Daimler's project
  • Exclusive inside knowledge within the SimulationX Community

    Baker Hughes, Hatebur, Hawe Hydraulik, Moog, OneSubsea and Putzmeister, to name just a few, use multiphysics simulation to simulate and optimize fluid power components and systems.

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    SimulationX enables even beginners to solve complex multiphysics tasks in a simple and reliable way

    The simulation program includes ready-made application packages for many typical development tasks for simulating hydraulic and pneumatic systems.

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