**Shock Compression of Porous Ceramics**

**Shock Compression of Porous Ceramics**

#### Yin Yu and Hongliang He Yin Yu and Hongliang He Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.72246

#### **Abstract**

Shock compression is a challenge for porous ceramics in application. In this chapter, numerical simulation and experimental observation have been introduced, which reveals generation of crack, damage, and fracture within porous ceramics upon shock wave loading. Simulation of a two-dimensional lattice-spring model explains the effects of voids and grain boundaries on the mesoscopic deformation features of shocked porous ceramics. Experiments confirm the fracture and fragmentation evolution in the post-shock ceramics. These understandings are conducive to the design, manufacture and usage of the porous ceramics under rapid impulsive loading. Furthermore, the concept of controllable fracture is proposed, which is a strategy to modulate the propagation of shock fracture in porous ceramics for the avoidance or delay of the shock-induced functional failure. It is evidenced that a "shielded region," i.e., free of severe shock fracture, could be formed with the sacrifice of a "damaged region" in the porous ceramics.

DOI: 10.5772/intechopen.72246

**Keywords:** porous ceramics, shock compression, lattice-spring model, deformation mechanisms, damage shielding

#### **1. Introduction**

Shock wave loading is generated often at impact, collision, and blast. A shock wave is a powerful amplifier of defects in that it activates pre-existing defects (e.g., microvoids, cracks, and grain boundaries), extends cracks, and breaks media. The main challenge of porous ceramics in the application upon shock wave loading is its nonstationary behavior due to crack, damage, and fracture of the heterogeneous structure [1–4]. Mechanical, electrical, and optical properties of ceramics are severely affected by shock waves, and consequently, it may deteriorate the designed functions of shocked ceramics, such as in the cases of high-strength ceramics for armor [5], piezoelectric and ferroelectric ceramics for converting mechanical energy to electrical energy [6–8] and transparent ceramics for optical measurements in shock experiments [9].

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

Hence, a good understanding of the dynamic response of porous ceramics under rapid impulsive loading is vital to the design, manufacture, and usage of these materials. To this objective, a two-dimensional lattice-spring model (LSM) has been newly established, and the shock compression behavior of porous ceramics is explored and the mechanisms and strategies for improving robustness are discussed.
