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  • 1.
    Patil, Aniket
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sand, Björnar
    Fransson, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Finite element simulation of punch through test using a continuous surface cap model2015Ingår i: Proceedings of the 23nd International Conference on Port and Ocean Engineering under Arctic Conditions: POAC 2015, Trondheim, Norway; 14-18 June 2015, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    An attempt has been made to calibrate the material model parameters of the continuous surface cap model with data from punch through tests performed in the Northern Gulf of Bothnia. An axisymmetric finite element model has been used to simulate the field tests. The continuous surface cap model based on a combination of elastic-plastic and continuum damage mechanics formulation is used as constitutive model for ice rubble. Material properties such as internal friction angle, cohesion and Young’s modulus are evaluated in a parametric study and the response is compared to the experimental data for the chosen test. An optimization algorithm is used for determining the parameters used for describing the continuous surface cap model. The material model parameters are chosen to get best fit to test load displacement curve. Conclusion has been drawn based on the application of continuous surface cap model on ice rubble.

  • 2.
    Patil, Aniket
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sand, Björnar
    Norut Northern Research Institute, Narvik.
    Fransson, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Smoothed particle hydrodynamics and continuous surface cap model to simulate ice rubble in punch through test2015Ingår i: Proceedings of the 23nd International Conference on Port and Ocean Engineering under Arctic Conditions: POAC 2015, Trondheim, Norway; 14-18 June 2015, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recent trend in computational mechanics shows considerable development of numerical methods to simulate discrete materials such as ice rubble. Ice rubble has highly nonlinear behavior and to simulate shear properties requires a new numerical method. An attempt has been made to simulate a punch through test using the Lagrangian mesh-free partial based method formulation known as smoothed particle hydrodynamics. A newly implemented material model in LS-Dyna called the continuous surface cap model has been used in this simulation. A continuous surface cap model based on a combination of elastic-plastic and continuum damage mechanics formulation is used as constitutive model for ice rubble. The material model parameters are chosen to get best fit to test load displacement curve. A brief overview of the smoothed particle hydrodynamics is given. Finally, the results from simulations have compared with experimental results.

  • 3.
    Bonath, Victoria
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Patil, Aniket
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Fransson, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sand, Björnar
    Laboratory testing of compressive and tensile strength on level ice and ridged ice from Svalbard region2013Ingår i: Proceedings of the 22nd International Conference on Port and Ocean Engineering under Arctic Conditions, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Compression and tensile strength properties are important input data for constitutive modelling. Still strength properties of ridged ice are not yet sufficiently investigated. During winter 2011 and 2012 field trips were performed to the Svalbard region with the aim to investigate structure and strength of pressure ridges. Core samples from different ridges and the surrounding level ice were taken and transported to the laboratory at Luleå University of Technology. Studies on thin sections of the ice samples under cross-polarized light delivered information about internal structure of the ice. Uniaxial compressive and tensile strength tests were performed with horizontal and vertical loading directions. The experimental procedure is explained in detail. Salinity and porosity were measured for each sample. In this paper the mechanical properties obtained from the testing are documented by consideration of crystal type, ice depth and total porosity.

  • 4.
    Patil, Aniket
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sand, Björnar
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Fransson, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Numerical simulations of shear properties of ice rubble: a shear box experiment2013Ingår i: Proceedings of the 22nd International Conference on Port and Ocean Engineering under Arctic Conditions: June 9-13, 2013 Espoo, Finland, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Ice rubble has highly nonlinear behavior and thus simulate shear properties requires sophisticated constitutive models including a relatively large number of parameters and complicated calibration procedures. An attempt has been made to simulate shear properties of ice rubble. A shear box experiment is chosen from test series performed by Fransson and Sandkvist (1985). In this paper a shear box test is simulated with nonlinear finite element code LS-Dyna. A newly implemented material model in LS-Dyna called continuous surface cap model (CSCM) has been used in this simulation. This model is proposed by Schwer and Murray (1994). For the sake of simplicity, experimental results are compared with Mohr-Coulomb material model. A brief overview of continuous surface cap model is given. Finally, comparisons with experimental results have been made.

  • 5.
    Patil, Aniket
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sand, Björnar
    Fransson, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Daiyan, Hamid
    Norut Northern Research Institute, Narvik.
    Constitutive Models for Sea Ice Rubble in First Year Ridges: A Literature Review2012Ingår i: International Association for Hydro-Environment Engineering and Research: 21st IAHR International Symposium on Ice / [ed] Yang LU, Dalian University of Technology Press, China: Dalian University of Technology Press, 2012, s. 623-638, artikel-id T11118Konferensbidrag (Refereegranskat)
    Abstract [en]

    Exploration and production of hydrocarbons in arctic areas demands stronger, lighter and safer offshore structures. Wind and sea currents are responsible for ice loads on structure. The design of these structures is based on load level which is usually determined by the drift ice features i.e. ice ridges and surrounding level ice fields if icebergs are not dominating in the area. Ridges drift and hit fixed or moored surface structures such as platforms or ships, or they may scour the seabed endangering pipelines and wellheads. Realistic Constitutive models will help to build more accurate numerical analysis of the ice load. It will decrease the capital costs for the offshore structures, resulting in more economic field development for arctic offshore. This literature review paper is focused on existing models used to simulate the constitutive behaviorof the ice rubble. In first chapter ridge types, their formation and typical geometrical features has been discussed. Second chapter gives a review of Ice Rubble Failure and Deformation Mechanisms are discussed. Third chapter gives a brief comparison of between discrete model and continuum model. Fourth chapter is about existing constitutive models which are proposedand used to simulate ice structure interaction process. Calibration, advantages and disadvantages has been discussed in this chapter. Lastly, a summery is given about paper. Readership require familiarity with constitutive modelling used in numerical analysis especially finite element analysis.

  • 6.
    Fransson, Lennart
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Patil, Aniket
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Andrén, Henrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Experimental investigation of friction coefficient of laboratory ice2011Ingår i: Proceedings of the 21st International Conference on Port and Ocean Engineering under Arctic Conditions, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Friction processes of rubber on ice, steel on ice and ice on ice have been investigated bymeasuring contact forces in controlled laboratory experiments. A carefully prepared ice platewas rotated at a constant speed and brought into contact with a ring on which torque andnormal load was measured. Replicas of the different types of standardized ice surfaces werestudied in microscope. Friction of rubber on ice reached a maximum value at a sliding speedof abt. 100 mm/min. At a temperature of -10°C this maximum friction coefficient decreasedwith increasing ice surface roughness. Friction of steel on ice increased with decreasing speedand no maximum value was obtained. Ice sliding on ice at low speed resulted in high frictionforces when sintering took place.

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