Tada-aki Tanabe

Detecting the size effect in concrete beams using nonlinear fracture mechanics

This paper shows that, the size effect in flexure and shear strength for different concrete and reinforced concrete beam sizes subjected to concentrated and uniformly distributed loads can be successfully predicted on the basis of nonlinear fracture mechanics. The analysis was carried out by a computer simulation using the program ANACS (advanced nonlinear analysis of concrete structures), which was originally developed by the authors. In this investigation, the fictitious crack model was adopted with two orthogonal rod elements which involves the nonlinear fracture mechanics through their constitutive model to simulate the discrete crack path and represent the localized crack zone. By combining the arc-length calculation technique with the fictitious crack model, the postpeak behaviour can be predicted well even for snapback instability.

Development of FEM Thermal Analysis for Concrete Structures with Pipe Cooling System

In this study, a new numerical method of pipe-cooling thermal analysis is presented in order to achieve arbitrary layout of the cooling pipe independent of FEM mesh arrangement. Then, some thermal analyses for concrete structural model with pipe cooling system are executed and validity of the proposed numerical method is discussed. As a result, it is confirmed that the proposed analytical procedure can simulate quite rational temperature histories despite of the cooling pipe layout independent of FEM mesh arrangement.

Post-peak Behavior of Shear Failing Beams Governed by Snapback Instability

This paper describes how snapback load-deflection relations of shear failing beams are numerically obtained using Arc Length Method with Selected Displacement Control Points. Identifying stress loading area while load decreases, failure process of snapback shear failure of a beam is clarified in the paper. The fundamental understanding of the phenomena is extended to failure concept of a structure through energy balance calculation.