Noncontact stress measurement from bare UHPC surface using Raman piezospectroscopy

Abstract

Raman piezospectroscopy was applied for noncontact stress measurement from bare ultrahigh‐performance concrete (UHPC). Microstructure and chemical characterization were conducted for 3 phases of UHPC samples, including unmixed concrete ingredients (Sample 1), cured concrete (Sample 2), and pulverized concrete (Sample 3). Rich contents of polycrystalline silica (quartz) were observed from all samples. The global and local piezospectroscopy coefficients were measured from compressive loading frame tests at 3.77 cm−1/GPa and 1.62–9.10 cm−1/GPa, respectively. The quartz fingerprint peak was observed at 460.50 cm−1 from stress‐free UHPC powder, which can be used as the zero‐stress state to determine absolute stress in existing concrete structures. The global absolute stress equation is presented using the global piezospectroscopy coefficient and the zero‐stress state.

Sensitivity Analysis of Modal Parameters of a Jacket Offshore Wind Turbine to Operational Conditions

“…Accurately modeling this relationship will help designers and owners better understand the OWT's dynamic response in different operational conditions and therefore help them with better fatigue life estimation. Modal parameters of linear dynamic systems can be identified using measurements collected from vibration sensors that are installed on the structure or using noncontact image-based sensors [8][9][10][11][12][13]. The natural frequencies of the first FA/SS modes of an OWT are fundamental parameters for the design of the tower and the foundation.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIII

“…Sendova and Jimenez carried out a synergistic thermo‐Raman and calorimetric kinetic study of the cation modifier's role in binary metaphosphate glasses . Yun and co‐workers described noncontact stress measurements from bare ultra high performance concrete surfaces using Raman piezo‐spectroscopy …”

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A Numerical Model to Predict the Relaxation Phenomena in Thermoset Polymers and Their Effects on Residual Stress during Curing, Part II: Numerical Evaluation of Residual Stress

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