method for designing and implementing hydraulic elements to achieve stable operating points under impact loads

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The continuous comparison between required and achieved product functions is one of the core activities in product development. Many of these validation activities take place in test environments to investigate the system behaviour under dynamic loads. Special cases of dynamic loads are cyclical impact loads. Those high loads act for a very short period of time and also a high energy is transferred to the system. These loads cannot be validated sufficiently up to now, as stable and adjustable operating points at cyclical impact loads and high excitation frequencies cannot be achieved with mechanical damping elements. Impact loads are often used to destroy materials. The material non-destructive validation of systems for impact applications, e.g. hammer drills or mining hammers, is increasing, since time and costs can be saved as the reproducibility of tests increases. The material non-destructive validation of these systems requires a high resilience of test environments, since a high damping performance together with a constant system behaviour is required. Own preliminary work has revealed that hydrostatic damping elements are capable of providing stable operating points for impact loads with low wear and adjustable conditions. Up to now, however, there is no support in the design of hydraulic damping elements for impact loads, as existing support only deals with designs regarding harmonic excitations with a lower damping performance. This project shall create a methodical support for the design of hydraulic damping elements for cyclical impact loads. The methodical support investigated in parallel to the design of such a damping element, which allows the identification of hydraulic effects, such as cavitation tendencies, under impact loads. Based on the impact behaviour of real surfaces and the damping behaviour of a mechanical element, which is able to absorb cyclical impact loads, but with non-constant operating behaviour, the requirements for a hydraulic system are determined. A hydraulic system is then simulated and designed. Design activities are summarized in the development method. Based on the design, the hydraulic solution is built as a research object. The physical validation of the hydraulic solution enables the identification of effects in hydraulic damping elements under impact loads, especially regarding the targeted adjustability or constant system behaviour. This enables the design of a control systems to achieve constant damping characteristics under changing impact excitations. Steps to build up a control system to achieve an adjustable and constant damping behaviour are dealt with in the development method and show the added value of hydraulic solutions.