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    Item type:Publication, Access status: without files ,
      54
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    Compression behavior of typical silicone rubbers for soft robotics applications at elevated temperatures
    (2021-04-12)
    Utkan, Doruk
    ;
    Maruthavanan, Duraikannan
    ;
    Schimanowski, Alex
    ;
    Seibel, Arthur
    In this communication, we analyze the compression behavior of typical silicone rubbers used in soft robotics applications at elevated temperatures. In particular, compression experiments according to ISO 7743 are performed with three mixing ratios (base polymer to curing agent) of Sylgard, Elastosil, and Ecoflex at 24 °C (room temperature), 30 °C, 40 °C, 50 °C, and 60 °C. Furthermore, typical hyperelastic material models are fitted to the measured stress-strain curves for room temperature. It is shown that the (third-order) Yeoh model shows the best overall fit, and the corresponding model parameters are stated.
    Publicationtype: Conference Paper
      43
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    Estimation of impact energy for seat seals in spring-operated pressure relief valves during the reseating process under compressible fluid service conditions
    (American Society of Mechanical Engineers (ASME), 2019-07)
    Schimanowski, Alex
    ;
    Schlattmann, Josef
    Spring operated pressure relief valves (SOPRVs) are used in many industrial fields for hazardous applications in order to protect people and environment as well as to reduce the risks of containment loss. Since SOPRVs are essential elements of safety systems, they are subject to strict functional and reliability requirements, which demand not only a proper disk lift but also give regulations concerning the maximum allowable valve tightness. However, despite the high practical importance of SOPRVs tightness through the whole life cycle, only initial tightness is considered in the literature and regulations. Therefore, in the present contribution we make an attempt to quantify the impact energy of the valve disk during the reseating of the valve, which is assumed to be the most relevant factor for repeated valve tightness. First, we present three different methods of increasing complexity for disk impact energy estimation. Subsequently, we demonstrate the application of these methods on the example of a SOPRV Type API 526 1E2 and discuss the findings. Finally, we consider a set of selected common used soft sealing materials and give implications for their usage within a range of set pressures and maximum disk lifts based on findings for the presented use case.
    Publicationtype: Conference Paper
      227
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    Systematic study of the effect of non-uniform seal stiffness on the contact stress in flat-faced soft-seated spring operated pressure relief valves
    (American Society of Mechanical Engineers (ASME), 2018)
    Schimanowski, Alex
    ;
    Seibel, Arthur
    ;
    Schlattmann, Josef
    Spring operated pressure relief valves (SOPRVs) are essential components of technical systems. As parts of safety systems, they protect people and the environment from technological hazards. Their ability to open at a predefined pressure is considered the most important feature. The reliability of this function depends on numerous operational and design factors. In this paper, we examine the effects of design measures on the mechanical loads in seat seals of SOPRVs. In particular, we evaluate the applicability of the principle of non-uniform system stiffness in order to systematically control the mechanical loads in seat seals for an exemplary case of a flat faced soft seated SOPRV. We systematically vary design parameters and accurately estimate the contact stresses as well as the set pressure by performing non-linear finite element analyses. We focus on the quasi-static case of a closed seal, since dynamic effects of the opening and closing processes are not within the scope of this work. In our contribution, we show that the application of these design measures can significantly influence both the initial contact stresses and the set pressure at a constant spring force. In particular, the effects of the taper angle are analyzed and discussed.
    Publicationtype: Conference Paper
      131
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    Methodological support for the selection of simplified equations of state for modeling technical fluids
    (American Society of Mechanical Engineers (ASME), 2017)
    Schimanowski, Alex
    ;
    Seibel, Arthur
    ;
    Schlattmann, Josef
    Many technical applications require accurate predictions of the thermodynamical state of the process fluid, which can be estimated from mathematical equations of state (EoS). Though the existing EoS are sufficiently accurate in the wide operating ranges for various technical fluids, they differ in terms of the complexity, and thus in computation costs. Therefore, for modeling and simulation of large technical systems, preferably simple and sufficiently accurate EoS are desired. The proposed approach presents a methodological support for the selection of appropriate EoS not only considering its accuracy but also its complexity. Furthermode, a cryogenic application involving nitrogen is used to demonstrate the proposed approach.
    Publicationtype: Conference Paper
      97