Application of level-set type topology optimization analysis for cavity shape estimation problem in structures based on non-destructive hammering test

14th World Congress in Computational Mechanics (WCCM) ECCOMAS Congress 2020 11 – 15 January 2021, Paris, France

Application of level-set type topology optimization analysis for cavity shape estimation problem in structures

based on non-destructive hammering test

Takahiko Kurahashi¹, Yuki Murakami², Shigehiro Toyama³, Fujio Ikeda⁴, Tetsuro Iyama⁵ and Ikuo Ihara⁶

1, 6 Nagaoka University of Technology,

1603-1, Kamitomioka, Nagaoka, Niigata 940-2188, Japan, [email protected]

2, 3, 4, 5, Nagaoka Institute of Technology, Nagaoka College,

888 Nishikatakai, Nagaoka, Niigata 940-8531 Japan

Key Words: Topology optimization, Cavity shape, Displacement response, Hammering test.

There are a lot of concrete structures exceeding service life in Japan, and it is necessary to perform inspections for the structures. It is desired that we can appropriately find a cavity in structures, because there is a possibility that a cavity causes collapse accident. In addition, it is important to know shape of cavity accurately due to difference of stress singularity on crack boundary line. Therefore, the level-set type topology optimization analysis for cavity in structures is carried out in this study. We focus on hammering test, and displacement response data on surface is employed for the identification of the cavity shape. In the level-set type optimization analysis, sensitivity for the level-set function is calculated based on the adjoint variable method [1],[2], and iterative computation for estimation of cavity shape is conducted by using a reaction diffusion equation with respect to the level-set function. Numerical experiments are carried out based on the above procedure, and some results are shown by changing numerical parameters in this study (See Fig.1.).

Fig.1 Comparison of cavity shape for each regularization parameter τ

REFERENCES

[1] T.Kurahashi, K.Maruoka and T.Iyama, Numerical shape identification of cavity in three dimensions based on thermal non-destructive testing data, Engineering Optimization, Vol.49, pp.434-448, 2016．

[2] T.Kurahashi, Investigations on boundary temperature control analysis considering moving body based on the adjoint variable and the fictitious domain finite element methods, Int. J.

Numeri.Meth. Eng.,Vol.103, pp.582-597, 2015.

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Case-A : τ=0.001 Case-B : τ=0.005 Case-C : τ=0.010