2011-JAP-光学玻璃激光激波冲击损伤阈值测量方法

(Received 16 November 2010; accepted 17 February 2011; published online 4 April 2011)
The shock wave driven by short laser pulse is used to study the damage of brittle material K9 glass. The damage morphology of K9 glass surface indicates that the material has experienced different loading modes, respectively, at the central area and the surrounding area of the shock wave. At the central area of shock wave, the wavefront is plane and has a uniform pressure distribution, the material mainly suffers a longitudinal shock pressure; but on the edge the shock wave, the wavefront is approximately spherical, besides longitudinal pressure, transverse tensile stress will emerge inside the material. In the latter case, the damage threshold of the material is much smaller than that in the case of compressing by longitudinal pressure only. According to the relationship between damage area and shock pressure, an experimental method is proposed to measure the damage threshold of materials under shock loading. The damage threshold of K9 glass under spherical shock wave is measured to be about 1.12 GPa; and the damage threshold under plane shock wave is estimated to be between 1.82 and 1.98 GPa. They are much bigger than the damage threshold under static pressure. This method could also be used to measure the damage threshold of other materials when loaded by dynamic pressure. VC 2011 American Institute of Physics. [doi:10.1063/1.3564961]
JOURNAL OF APPLIED PHYSICS 109, 073103 (2011)
Shock induced damage and damage threshold of optical K9 glass investigated by laser-driven shock wave
Yunfei Song,1 Guoyang Yu,1 Lilin Jiang,1 Xianxu Zheng,2 Yuqiang Liu,1 and Yanqiang Yang1,a)
In this article, an experimental method is proposed to measure the damage threshold of brittle materials under shock loading. The dynamic high pressure is loaded on target by a laser driven shock wave. The damage morphology under different shock pressure is observed through changing the energy of excitation pulse. The size of the damage spots is measured and the damage threshold can be calculated out based on the relationship between damage area and shock
1Center for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology, Harbin, China 2Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuanle materials will break up when being compressed by high pressure. The damage threshold of material is an important parameter which can reflect the structural strength. The failure of most materials pressed by static pressure has been familiar to engineers, but it is an interesting issue whether the material under shock loading exhibits the same behavior as that under static pressure.1–3 In some special conditions, the material suffers an intense shock, such as how satellites in outer space are frequently impacted by micrometeorite with high speed of tens of km/s, therefore, it is desirable to investigate the damage of materials caused by the shock wave in the experiment. In a traditional investigation, the shock wave is produced by a gas-gun or an explosive,4,5 the peak pressure of the shock wave may be more than 100 GPa. However, a disadvantage of these kinds of manners is that it always needs a long period of time to prepare the experiment, and it is difficult to repeat the experiment in the same conditions; furthermore, the shock produced in these manners usually causes destructive damage to the target which makes the post-shock examination impossible. In the past 30 years, short pulse lasers have been applied more and more to the study of shock phenomenon because laser driven shock wave with high energy density has a lot of advantages, such as high peak pressure, ultrafast rise time of shock front, and a high repetition rate. Nowa-
a)Author to whom correspondence should be addressed. Electronic mail: yqyang@.
days, there is a greater understanding of the characteristics and effects of laser driven shock wave,6–8 and technology has also been used to study the damage of materials induced by shock loading. Using a laser driven shock wave to study the damage of materials, a high pressure can be loaded on the target in several nanosecond or less;9 moreover, the peak pressure of laser shock is high, but the duration is very short, so the whole shock wave only carries little energy. Therefore, the serious destruction of target can be avoided, which makes the post-shock examination much easier. In addition, it is easy to change the intensity of laser driven shock wave, which is mainly dependent on the energy of excitation laser pulse. This characteristic makes it convenient to measure the damage threshold of materials under shock loading through an experimental method. The characteristics of laser driven shock wave have been studied in many previous works and some papers have reported the investigation about the damage induced by laser shock, for instance, Resseguier et al, who has done a lot of work in studying the spallation of materials caused by laser driven shock wave.10–12 However, there is still no published work about how to measure the damage threshold of materials under strong shock loading.