Investigation of the effect of prescribed coupled motions on the power production of a floating offshore wind turbine

Floating offshore wind turbines are subjected to platform motions that modify the local velocity experienced by the rotor. This work analyzes how variations in the platform motions affect the aerodynamic power of a floating wind turbine. Idealized wind conditions and rigid wind turbine are considered. The platform motions are prescribed by...

Analysis of ESAFORM 2021 cup drawing benchmark of an Al alloy, critical factors for accuracy and efficiency of FE simulations

This article details the ESAFORM Benchmark 2021. The deep drawing cup of a 1 mm thick, AA 6016-T4 sheet with a strong cube texture was simulated by 11 teams relying on phenomenological or crystal plasticity approaches, using commercial or self-developed Finite Element (FE) codes, with solid, continuum or classical shell elements and different...

A frequency-time domain method for annual energy production estimation in floating wind turbines

A new method is proposed to estimate a floating wind turbine's annual energy production (AEP) using frequency and time-domain design techniques. The approach demonstrated herein estimates the AEP by performing a convolution between the floating platform response and the response power operators (RPOs) that map the average power produced by...

Development of a physics-based theory for mixed mode I/II delamination onset in orthotropic laminates

This paper demonstrates how the critical strain energy density in the delamination tip vicinity may be used to explain the physics of delamination growth under mixed mode I/II. A theory previously proposed to physically relate mode I and mode II delamination growth is further extended towards describing the onset of mixed mode I/II...

Towards fundamental understanding of interlaminar ply delamination growth under mode II and mixed-mode loading

In a context of many studies addressing delamination growth in laminated composites, this thesis provides understanding of the underlying physics of this phenomenon. The models currently used to assess delamination growth are phenomenological in nature and rely almost solely on curve fittings and experimental data. These empirical models are...

Towards a physics-based relationship for crack growth under different loading modes

In an attempt to understand quasi-static delamination growth under mixed mode loading conditions from a physics-based perspective, this work first evaluated cracking in isotropic materials. The critical Strain Energy Density (SED) approach is adopted, because physically the onset of crack growth is expected to occur when the energy available...

Understanding mixed-mode cyclic fatigue delamination growth in unidirectional composites: An experimental approach

Due to the lack of fundamental knowledge of the physics behind delamination growth, certification authorities currently require that composite structures in aircraft are designed such that any delamination will not grow. This usually leads to an overdesign of the structure, hampering weight reductions. In real structures, delaminations tend...

Breaking the geometric magnetic frustration in controlled off-stoichiometric LuMn1+zO3+o compounds

Energy based study of quasi-static delamination as a low cycle fatigue process

This work proposes to treat quasi-static mode I delamination growth of CFRP as a low-cycle fatigue process. To this end, mode I quasi-static and fatigue delamination tests were performed. An average physical Strain Energy Release Rate (SERR), derived from an energy balance, is used to characterize the energy released in crack extension. The...

Inter-collge cooperation as a tool for a campus environmentalization: Strengthening the cooperation project between Universidade de São Paulo, Brazil, and Universidad Autónoma de Madrid, Spain

For several decades, environmental variables have been introduced to universities, either in curriculum activities or campus management. Following such trend, Universidade de São Paulo (USP), in Brazil, and Universidad Autónoma de Madrid (UAM), in Spain, created, throughout the 1990s, organizational structures able to coordinate environmental...

Experimental technique for diagnosing fractures in shaft lines applied to a ROV supply vessel