Sand-to-Concrete Interface Response to Complex Load Paths in a Large Displacement Shear Box

2008 ◽  
Vol 31 (4) ◽  
pp. 100220 ◽  
Author(s):  
L. D. Suits ◽  
T. C. Sheahan ◽  
Jesús E. Gómez ◽  
George M. Filz ◽  
Robert M. Ebeling ◽  
...  
Keyword(s):  
Large Displacement ◽  
Complex Load ◽  
Load Paths ◽  
Shear Box ◽  
Concrete Interface

Push-Over Response of a Jack-Up on Sand of Different Relative Densities

2009 ◽  
Author(s):  
Britta Bienen ◽  
Mark J. Cassidy ◽  
Christophe Gaudin
Keyword(s):  
Wind Waves ◽  
Scaled Model ◽  
Environmental Loading ◽  
Complex Load ◽  
Geotechnical Centrifuge ◽  
Overall Response ◽  
Load Paths ◽  
Numerical Predictions ◽  
Macro Element ◽  
Jack Up

On location offshore, jack-up structures are subject to environmental loading from wind, waves and current in addition to self-weight. Over the operational period of the jack-up, the environmental loading on a given site may not be unidirectional along the jack-up’s ‘axis of symmetry’ but may act from different directions and/or be non-collinear (i.e. wind acting from a different direction than waves and current), resulting in complex load paths at the spudcan footings. This paper discusses load paths obtained from experiments on a scaled model jack-up for two different horizontal loading directions and illustrate the implications of spudcan load paths for the overall response of a jack-up to failure. Similar tests were performed at two different relative sand densities, allowing the influence of relative density on jack-up behavior to be investigated. Similitude to the prototype was achieved by conducting the experiments in a geotechnical centrifuge at 200g. The paper concludes with numerical predictions of the experimentally measured response, using a macro-element to model the soil-spudcan interaction coupled to a structural finite element program. The footing macro-element has been developed based on plasticity theory and single footing experiments, but its ability to predict the respective load paths of each of the spudcans in a multi-footing system is demonstrated here. The paper further provides the experimentally measured jack-up push-over capacity and numerical predictions in the context of recommendations of current guidelines. This highlights the requirement of nonlinear elasto-plastic modelling of the load-displacement behavior of the jack-up foundations in order to predict the overall response of the system.

Predicting the Magneto-Mechanical Behavior of MSMAs Subject to Complex Load Paths

2012 ◽  
Author(s):  
Heidi P. Feigenbaum ◽  
Constantin Ciocanel ◽  
Alex Waldauer
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Mechanical Behavior ◽  
Shape Memory ◽  
Compressive Stress ◽  
Complex Loading ◽  
Model Parameters ◽  
Variable Load ◽  
Complex Load ◽  
Load Paths

The microstructure of magnetic shape memory alloys (MSMAs) is comprised of tetragonal martensite variants, each with their preferred internal magnetization orientation. In the presence of an external magnetic field, the martensite variants tend to reorient so that the preferred internal magnetization aligns with the external magnetic field. As a result, MSMAs exhibit the shape memory effect when there is a magnetic field in the vicinity of a material point. Furthermore, the tetragonal nature of the martensite variants allows for a compressive stress to cause variant reorientation. This paper studies the magneto-mechanical behavior of MSMAs under various load paths, including complex loading conditions where both the applied magnetic field and compressive stress vary simultaneously. Typically, MSMAs have been studied experimentally and modeled mathematically with either axial compressive stress or transverse magnetic field varying and the other remaining constant. For each load case, the mathematical models are calibrated with a set of experimental data that mimics those to be predicted. Model parameters have been found to be quite different when the calibration was performed with experimental results from different load cases. This work investigates if current models, namely the Kiefer and Lagoudasmodel or the Waldauer et al. model, are capable of predicting both of the typical loading configurations mentioned above with a single calibration. Furthermore, this work uses the Waldauer et al. model to simulate more complex loading, where an MSMA element is subject to simultaneously varying stress and field; this type of loading might occur if an actuator is being designed to displace a variable load over a controlled distance.

The Challenges of Modeling Magnetic Shape Memory Alloys Under Complex Load Paths

2010 ◽  
Author(s):  
Alex B. Waldauer ◽  
Heidi P. Feigenbaum ◽  
Constantin Ciocanel
Keyword(s):  
Magnetic Field ◽  
Shape Memory Alloys ◽  
Mechanical Behavior ◽  
Shape Memory ◽  
Compressive Stress ◽  
Test Specimen ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloys ◽  
Complex Load ◽  
Load Paths

Kiefer and Lagoudas proposed a thermodynamic model for predicting the magneto-mechanical behavior of magnetic shape memory alloys (MSMAs) and then confirmed their model experimentally [1]. The model was calibrated by placing the test specimen under a constant magnetic field and a varying compressive stress. Later, Feigenbaum and Ciocanel [2] used the model to predict behavior under a constant compressive stress and a varying magnetic field. Because the two experiments were done by different researchers on different specimens, the calibration gave different values for material paremeters. In this work, through experimental results from tests performed on the same specimen by the same researchers, the Kiefer and Lagoudas model, with any hardening function, will be shown to be unable to be calibrated so as to accurately predict the magneto-mechanical behavior of a specimen under both types of loading conditions.

Study on shear performance of the connection with external stiffening ring between square steel tubular column and unequal-depth steel beams

2020 ◽  
pp. 136943322098166
Author(s):  
Shuhao Yin ◽  
Bin Rong ◽  
Lei Wang ◽  
Yiliang Sun ◽  
Wuchen Zhang ◽  
...  
Keyword(s):  
Failure Modes ◽  
Plastic Hinge ◽  
Steel Tube ◽  
Nonlinear Finite Element ◽  
Steel Beams ◽  
Finite Element Models ◽  
Test Results ◽  
Panel Zone ◽  
Load Paths ◽  
Shear Performance

This paper studies the shear performance of the connection with the external stiffening ring between the square steel tubular column and unequal-depth steel beams. Two specimens of interior column connections were tested under low cyclic loading. The deformation characteristics and failure modes exhibited by the test phenomena can be summarized as: (1) two specimens all exhibited shear deformation in steel tube web of the panel zone and (2) weld fracture in the panel zone and plastic hinge failure at beam end were observed. Besides, load-displacement behaviors and strain distributions have been also discussed. The nonlinear finite element models were developed to verify the test results. Comparative analyses of the bearing capacity, failure mode, and load-paths between the equal-depth and unequal-depth beam models have been carried out.

scholarly journals Experimental Characterization of the FRCM-Concrete Interface Bond Behavior Assisted by Digital Image Correlation

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1154
Author(s):  
Dario De Domenico ◽  
Antonino Quattrocchi ◽  
Damiano Alizzio ◽  
Roberto Montanini ◽  
Santi Urso ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Front Face ◽  
Full Field ◽  
Bond Behavior ◽  
Externally Bonded ◽  
Strengthening Technique ◽  
Concrete Interface

Digital Image Correlation (DIC) provides measurements without disturbing the specimen, which is a major advantage over contact methods. Additionally, DIC techniques provide full-field maps of response quantities like strains and displacements, unlike traditional methods that are limited to a local investigation. In this work, an experimental application of DIC is presented to investigate a problem of relevant interest in the civil engineering field, namely the interface behavior between externally bonded fabric reinforced cementitious mortar (FRCM) sheets and concrete substrate. This represents a widespread strengthening technique of existing reinforced concrete structures, but its effectiveness is strongly related to the bond behavior between composite fabric and underlying concrete. To investigate this phenomenon, a set of notched concrete beams are realized, reinforced with FRCM sheets on the bottom face, subsequently cured in different environmental conditions (humidity and temperature) and finally tested up to failure under three-point bending. Mechanical tests are carried out vis-à-vis DIC measurements using two distinct cameras simultaneously, one focused on the concrete front face and another focused on the FRCM-concrete interface. This experimental setup makes it possible to interpret the mechanical behavior and failure mode of the specimens not only from a traditional macroscopic viewpoint but also under a local perspective concerning the evolution of the strain distribution at the FRCM-concrete interface obtained by DIC in the pre- and postcracking phase.

Sign in / Sign up

Export Citation Format

Share Document