Comparisons of thermal radiation characteristics between rocks and PMMA subjected to free-fall impacts

Lixin Wu, Yuhua Wu, Wenzhong Shi, Sheng Zhong, Daqing Ge

Research output: Journal article publicationConference articleAcademic researchpeer-review

1 Citation (Scopus)


Utilizing the Thermal Infrared (TIR) imaging technology, the transient process of solids (Three kinds of rocks and one kind of PMMA) impacted by free-falling steel balls are monitored with an infrared camera. It is discovered that: (1)as for rock materials, the increments of IR temperature (both the maximum and average, i.e., Δ Tmax and Δ Tavr) are all linear related to the impacting height, the difference are the statistical correlation coefficients (R): relatively homogeneous rock (marble, R=0.93-0.95); non-homogeneous rocks (granite: R=0.88-0.92; gabbro: R=0.80-0.84); while for PMMA, there exists a critical height(h ≈ 5m), within this height, ΔTmax is quadratic related and Tavr is linear related to the impacting height, and when above this critical height, both Δ Tmax and ΔTavr are linear related, comparison to rocks, the statistical correlation coefficients are somewhat higher(R=0.94-0.96); (2) the amplitude of IR temperature increments are different, it is somewhat less of IR temperature variations for relatively hard rocks (granite) than others (gabbro, marble and PMMA), for example, when impacted at a height of 2 meter with a standard ball(1inch in diameter), the higher ΔTmax≈2-4K, while others are within 1K, and (3) it is verified that the parameters about the impaction could be well inversed qualitatively to quantitatively, not only the type of rocks can be identified exactly, but also the impacting height can be accurately estimated especially for the relatively homogenous materials, as for marble rock and PMMA, the relative mean errors of inversion are less than 11.3% and 6.2%, respectively.

Original languageEnglish
Article number34
Pages (from-to)264-271
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2005
EventThermosense XXVII - Orlando, FL, United States
Duration: 29 Mar 200531 Mar 2005


  • Back analysis
  • Free-fall impact
  • PMMA
  • Rock
  • Thermal radiation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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