Acta Mechanica Solida Sinica. Vol. 20. No. 2. June 2007 ISSN08949166 Published by AMSS Press, Wuhan, China. DOI: 10.1007/ s10338-007-0717-x FRACTURAL PROCESS AND TOUGHENING MECHANISM OF LAMINATED CERAMIC COMPOSITES *x Zhang Yafang Faculty of Civil Engineering, Guangzhou University, Guangzhou 510006, China) Tang Chun'an2,3 Zhang Yongbin Liang Zhenzao2 School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian 116024, China) (Research Center for Numerical Test on Material Failure, Dalian University, Dalian 116622, China) Received 9 December 2006: revision received 13 June 2007 ABSTRACT Based on the model of multi-layer beam and the assumption of micro-inhomogeneity of material, the 3D fractural characteristics of laminated ceramic composites have been studie with numerical simulation. Under three-point bending load, crack initiation, coalescence, propa- gation, tuning off in the weak interface and final rupture have been simulated. The spatial distri- bution and evolution process of acoustic emission are also presented in the paper. The simulation verifies the primary mechanism of the weak interface inducing the crack to expand along there and absorbing the fractural energy. The disciplinary significance of the effect of strength and prop- erties of material on the toughness and strength of laminated ceramic composites is, therefore, discussed in this paper KEY WORDS laminated ceramic composite, toughening, numerical simulation I INTRODUCTION Ceramic composites are now widely applied in aeronautical and space engineering, metallurgy, civil engineering and automotive manufacturing due to the advantages such as high strength, high stiffness, good endurance of high temperature and corrosion, etc. However, the most critical obstructs on such applications is brittleness. How to strengthen and toughen the ceramic composite is a hot topic in recent Soft layers are combined with ceramic's brittle structure, so the laminated ceramic composites could be treated as a bionic structure, similar to that of shelves and bones in nature. Traditionally, the ap- proaches to improving toughness could be simply summarized as faults elimination. However, toughening mechanism of the laminated ce different and particular. Since Clegg et al. L published their work in Nature, many studies have been carried out in material preparation, fractural characteristics mechanical characteristics and toughening mechanism in this field(2-5 In these studies, some researchers, like Chang[6 and Guol7l tried to apply numerical methods to this field. Up to date, however, most of these studies were two-dimensional ones. If a three-dimensional CorrespondingauthorE-mail:zhangyafang2004@163.com unding by: S&T Project No. 2006B14601004 gong Province: S&T Project No. 62047, Educational Bureau, Guanzhou City and Fund of Natural Science, Guangdong Province(No. 05001885)Published by AMSS Press, Wuhan, China. DOI: 10.1007/s10338-007-0717-x Acta Mechanica Solida Sinica, Vol. 20, No. 2, June, 2007 ISSN 0894-9166 FRACTURAL PROCESS AND TOUGHENING MECHANISM OF LAMINATED CERAMIC COMPOSITES Zhang Yafang1 ( 1Faculty of Civil Engineering, Guangzhou University, Guangzhou 510006, China) Tang Chun’an2,3 Zhang Yongbin3 Liang Zhenzao2 ( 2School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian 116024, China) ( 3Research Center for Numerical Test on Material Failure, Dalian University, Dalian 116622, China) Received 9 December 2006; revision received 13 June 2007. ABSTRACT Based on the model of multi-layer beam and the assumption of micro-inhomogeneity of material, the 3D fractural characteristics of laminated ceramic composites have been studied with numerical simulation. Under three-point bending load, crack initiation, coalescence, propa￾gation, tuning off in the weak interface and final rupture have been simulated. The spatial distri￾bution and evolution process of acoustic emission are also presented in the paper. The simulation verifies the primary mechanism of the weak interface inducing the crack to expand along there and absorbing the fractural energy. The disciplinary significance of the effect of strength and prop￾erties of material on the toughness and strength of laminated ceramic composites is, therefore, discussed in this paper. KEY WORDS laminated ceramic composite, toughening, numerical simulation I. INTRODUCTION Ceramic composites are now widely applied in aeronautical and space engineering, metallurgy, civil engineering and automotive manufacturing due to the advantages such as high strength, high stiffness, good endurance of high temperature and corrosion, etc. However, the most critical obstructs on such applications is brittleness. How to strengthen and toughen the ceramic composite is a hot topic in recent years. Soft layers are combined with ceramic’s brittle structure, so the laminated ceramic composites could be treated as a bionic structure, similar to that of shelves and bones in nature. Traditionally, the ap￾proaches to improving toughness could be simply summarized as faults elimination. However, toughening mechanism of the laminated ceramic is different and particular. Since Clegg et al.[1] published their work in ‘Nature’, many studies have been carried out in material preparation, fractural characteristics, mechanical characteristics and toughening mechanism in this field[2–5]. In these studies, some researchers, like Chang[6] and Guo[7] tried to apply numerical methods to this field. Up to date, however, most of these studies were two-dimensional ones. If a three-dimensional Corresponding author. E-mail: zhangyafang2004@163.com Funding by: S&T Project No.2006B14601004, Guangdong Province; S&T Project No.62047, Educational Bureau, Guanzhou City and Fund of Natural Science, Guangdong Province (No.05001885).