Hydraulic Jack

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S. Srairi - One of the best experts on this subject based on the ideXlab platform.

Gérald Portemont - One of the best experts on this subject based on the ideXlab platform.

  • Static and dynamic bearing failure of carbon/epoxy composite joints
    Composite Structures, 2018
    Co-Authors: Gérald Portemont, Julien Berthe, Alain Deudon, François-xavier Irisarri
    Abstract:

    Mechanical fastening is a common method used to join composite materials in aeronautical industry. Various studies have been performed dedicated to the behaviour of composite bolted joints under quasi-static loadings, but only few studies deal with the dynamic behaviour (crash or impacts). The aim of this work is to study the loading rate influence on the bearing response of a carbon/epoxy laminate loaded by a pin. For that purpose, a double shear test fixture has been specially designed to measure the global behaviour and the local response around the pin. Infrared thermography and Digital Image Correlation techniques have been used to detect, map and characterize dissipative phenomena evolution. The tests have been performed on a servo-Hydraulic Jack with a loading rate ranging from 10 −4 m/s to 1 m/s. An increase of the peak bearing load of more than 20% is observed with the loading rate increase. A decrease of the load plateau of more than 60% is obtained. Simultaneous measurements of thermal and kinematic fields in this work give access to the evolution of the damage-related dissipative phenomena close to the pin. These dissipative phenomena were found to be significantly dependent on the loading rate.

  • Temperature effects on the time dependent viscoelastic behaviour of carbon/epoxy composite materials: Application to T700GC/M21
    Materials and Design, 2014
    Co-Authors: Julien Berthe, Mathias Brieu, Eric Deletombe, Gérald Portemont
    Abstract:

    In this study, strain rate and low temperature dependencies of the viscoelastic behaviour of the T700GC/M21 composite material are characterised and analysed. Dynamic tests for various environmental temperatures are performed on Hydraulic Jack equipped with an environmental chamber. Three speeds, between 8.33 * 10−4 m s−1 and 0.5 m s−1, at three temperatures (20 °C, −40 °C and −100 °C) are tested. The increase of the shear modulus with the decrease of the temperature is more pronounced between −40 °C and −100 °C than between 20 °C and −40 °C. Complementary DMA (Dynamic Mechanical Analysis) tests are performed on the M21 epoxy resin to characterise the viscoelastic behaviour of the matrix which contributes to the viscoelastic behaviour of the laminate. DMA tests highlight a low temperature transition called β transition (−67 °C for the 1 Hz test) which is responsible of the larger increase of the storage modulus, for the epoxy matrix, between −40 °C and −100 °C. Consequently the β transition could also be at the origin, for the composite, of the observed larger increase of the shear modulus with respect to the strain rate, for strain rates higher than 10 s−1.

E Markiewicz - One of the best experts on this subject based on the ideXlab platform.

  • strain rate dependence in spot welds non linear behaviour and failure in pure and combined modes i ii
    International Journal of Impact Engineering, 2010
    Co-Authors: Bertrand Langrand, E Markiewicz
    Abstract:

    When modelling assemblies for structural crashworthiness computations, fasteners are usually only characterised by their tension and shear strengths. However, for large deformations potentially leading to the failure of the assembly, joints are often loaded in combined modes, and the usual macro models fail to predict the assemblies' non-linear behaviour and rupture. In this paper, an advanced experimental procedure is proposed for testing and modelling spot-welded plates in pure and combined modes I/II under quasi-static and dynamic loading conditions. Obtained using a Hydraulic Jack and the Split Hopkinson Pressure Bar technique, the experimental results make it possible to analyse the mechanical strength (and the displacement rate dependence) of spot-welded plates. The non-linear behaviour and failure of experimental spot welds were proved to be strain-rate dependent in pure and combined mode I/II loading conditions. Our analysis showed that ultimate strengths in pure modes I and II would be particularly strain-rate dependent. Based on these results, a strain-rate dependent model was developed for ultimate loads in pure opening mode (tensile load) and presented in this paper. A computational approach for building a model for ultimate loads in pure shear mode is also discussed.

S S Chen - One of the best experts on this subject based on the ideXlab platform.

  • experimental performance and modeling study of a 30 year old bridge with steel bearings
    Transportation Research Record, 1993
    Co-Authors: John B Mander, S S Chen
    Abstract:

    The strength and deformation characteristics of 30-year-old steel bridge bearings, both fixed and expansion, are presented on the basis of field and laboratory experiments. The interaction between the deck and the substructure is analyzed. Field experiments were performed on a two-span, slab-on-girder bridge at Niagara Falls, New York, where the bridge deck was cyclically loaded over the central pier by alternating the placement of a Hydraulic Jack, forcing the spans apart in transverse and longitudinal directions. For the transverse tests, a ratio of about 1.5 of high lateral force to tributary weight was observed without bearing failure. Overall deformation was due mostly to diaphragm action between the deck and bearings, with only minimal movement in the bearings themselves. For longitudinal loading the expansion bearings did not slide on the bronze-steel sliding surface as expected, but the sole plate slid at a friction coefficient of about 0.6. An analytical study of the longitudinal test is presented in an attempt to account for the effects of girder depth and to identify the abutment stiffness from the results of the field experiments. The conclusion is that such bearings should behave satisfactorily in the event of a moderate earthquake such as may be expected in the eastern and central United States.

H. Imine - One of the best experts on this subject based on the ideXlab platform.

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