Supplemental Material: Nonlinear fault damage zone scaling revealed through analog modeling

(1) Movie and description of displacement gradient field evolution; (2) movie of strain fields evolution; (3) cummulative displacement field; (4) displacement gradient profiles through faults; (5) volumetric strain profiles through faults; (6) mechanical properties of the frictional layer; (7) images and parametric data of all the models; (8) a graph of all the measured D-T data; and additional information on the method and scaling to nature.<br>

Supplemental Material: Nonlinear fault damage zone scaling revealed through analog modeling

(1) Movie and description of displacement gradient field evolution; (2) movie of strain fields evolution; (3) cummulative displacement field; (4) displacement gradient profiles through faults; (5) volumetric strain profiles through faults; (6) mechanical properties of the frictional layer; (7) images and parametric data of all the models; (8) a graph of all the measured D-T data; and additional information on the method and scaling to nature.<br>

Absolute Measurement of Material Nonlinear Parameters Using Noncontact Air-Coupled Reception

Nonlinear ultrasound is often employed to assess microdamage or nonlinear elastic properties of a material, and the nonlinear parameter is commonly used to quantify damage sate and material properties. Among the various factors that influence the measurement of nonlinear parameters, maintaining a constant contact pressure between the receiver and specimen is important for repeatability of the measurement. The use of an air-coupled transducer may be considered to replace the contact receiver. In this paper, a method of measuring the relative and absolute nonlinear parameters of materials is described using an air-coupled transducer as a receiver. The diffraction and attenuation corrections are newly derived from an acoustic model for a two-layer medium and the nonlinear parameter formula with all corrections is defined. Then, we show that the ratio of the relative nonlinear parameter of the target sample to the reference sample is equal to that of the absolute nonlinear parameter, and this equivalence is confirmed by measurements on three systems of aluminum samples. The proposed method allows the absolute measurement of the nonlinear parameter ratio or the nonlinear parameter without calibration of the air-coupled receiver and removes restrictions on the selection of reference samples.

A numerical finite element study on connections of SFRC offshore wind towers with prestressed CFRP reinforcement and steel connectors

The growing need for sustainable production of electricity highlights the importance and the necessity of having higher number and more effective offshore wind towers. The rapid growth of offshore wind towers is estimated to produce 4% of electricity demands in Europe by the end of 2020. The research described in this paper is part of a project dedicated for the development of innovative structural system using advanced materials for lightweight and durable offshore towers. Specifically, it discusses the nonlinear finite element modelling of the connection between representative prefabricated rings of offshore wind tower made by steel fibre reinforced concrete (SFRC), and prestressed by a hybrid system of carbon fibre reinforced polymers (CFRP) bars and steel strands. This connection is assured by post-tension high steel strength cables and concrete-concrete shear friction width an idealized geometric configuration of the faces in contact. The model takes into account the loads from the rotor, wind and water currents, by considering the critical loading conditions for the safety verifications of serviceability and ultimate limit states. The material nonlinear analyses are carried out with FEMIX V4.0 software, considering a 3D constitutive model capable of simulating the relevant nonlinear features of the SFRC, and interface finite elements for modelling the shear friction of the concrete-concrete surfaces in contact. The parametric analyses involve the influence on the relevant results of the SFRC fracture parameters, pre-stress level of the reinforcements, shape of interlock mechanism, friction angle and interface cohesion.