Measurement of Three-Dimensional Anisotropic Thermal Diffusivities for Carbon Fiber-Reinforced Plastics Using Lock-In Thermography

Ishizaki, Takuya; Nagano, Hosei

doi:10.1007/s10765-014-1755-5

Cited by 26 publications

(2 citation statements)

References 10 publications

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“…In the actual measurement, the heating frequency is limited to avoid the in uence of the temperature wave re ection at the sample edge because the actual sample has a nite shape [19,20].…”

Section: Measurement Principlementioning

confidence: 99%

Measurement of Microscopic Thermal Diffusivity Distribution for Ryugu Sample by Infrared Lock-in Periodic Heating Method

et al. 2023

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The thermophysical properties of small Solar System bodies are essential to be determined, on which the thermal evolution of small bodies largely depends. The carbonaceous asteroid Ryugu is one of the small undifferentiated bodies formed in the early Solar System. Hayabusa2 explored the asteroid Ryugu and returned the surface samples in 2020 for detailed on-ground investigation, including measurements of thermal properties. Because the available sample amount was limited, this study developed a novel method to measure the thermal diffusivity of small and irregularly shaped samples of about 1 mm in diameter by combining lock-in thermography and periodic heating methods on the microscale. This method enables us to measure the thermal diffusivity of both at-plate and granular shape samples by selecting the suitable detecting direction of the temperature response. Especially, when the sample has a at-plate shape, the anisotropic distribution of the in-plane thermal diffusivity can be evaluated. This method was applied to six Ryugu samples, and the detailed anisotropic distribution of the thermal diffusivity was obtained. The measurement results showed that the samples show local thermal anisotropy caused by cracks and voids. The average thermal diffusivity among all samples was (2.8 − 5.8) × 10 − 7 m 2 /s. Based on the density and speci c heat of the samples obtained independently, the thermal effusivity was estimated to be 791 − 1253 J/(s 1/2 m 2 K), which is de ned as the resistance of surface temperature to the change of thermal input. The determined thermal effusivity, often called thermal inertia in planetary science, is larger than the observed value of 225 ± 45 J/(s 1/2 m 2 K) of the asteroid Ryugu's surface, obtained from the diurnal temperature change of the rotating asteroid by a thermal infrared camera onboard Hayabuas2. This difference is likely to be attributed to the difference in the analytical scale between the sample and the surface boulders compared with the thermal diffusion length. Consequently, it was found that the present result is more representative of the thermal diffusivity and thermal inertia of individual Ryugu particles.

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“…In the actual measurement, the heating frequency is limited to avoid the in uence of the temperature wave re ection at the sample edge because the actual sample has a nite shape [19,20].…”

Section: Measurement Principlementioning

confidence: 99%

Measurement of Microscopic Thermal Diffusivity Distribution for Ryugu Sample by Infrared Lock-in Periodic Heating Method

et al. 2023

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“…Conventional methods such as the flash method are mainly limited to relatively large defects such as delamination caused by the impact of flying objects and quality inspection after repair. The authors have developed a method to measure the thermal diffusivity for CFRP based on a laser-periodic-heating method using lock-in thermography (LIT) [5,6,7] and proposed a method to quantify fatigue damage of CFRP [8,9]. The method measures the effective thermal diffusivity 𝐷 𝑒 in the out-of-plane direction of CFRP laminates.…”

Section: Introductionmentioning

confidence: 99%

Lock-in thermographic measurement and model-based evaluation of effective thermal diffusivity to quantify early stage fatigue damage of CFRP

Fujita,

Natsuko,

Abe

et al. 2023

Thermosense: Thermal Infrared Applications XLV

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Fatigue characteristics of carbon fiber reinforced plastics (CFRP) are an important factor in predicting the design life of structures such as wind turbine blades. Due to the anisotropic and heterogeneous structure of CFRP, design life prediction under fatigue stress is a challenging task. The authors proposed an approach to assess fatigue damage at the microscale using a laser-periodic-heating method based on lock-in thermography (LIT). It assumes that the rate of fatigue progression correlates with the number of micro-voids, micro-cracks, and fiber/resin delamination that inhibit heat transfer. The effective thermal diffusivity in the out-of-plane direction of CFRP laminates, which were tested under fatigue loading, showed a decreasing trend with the number of loading cycles.

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Geometrical Effect on Thermal Conductivity of Unidirectional Fiber-Reinforced Polymer Composite along Different In-plane Orientations

Fang

Wang

et al. 2017

Appl Compos Mater

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Measurement of Three-Dimensional Anisotropic Thermal Diffusivities for Carbon Fiber-Reinforced Plastics Using Lock-In Thermography

Cited by 26 publications

References 10 publications

Measurement of Microscopic Thermal Diffusivity Distribution for Ryugu Sample by Infrared Lock-in Periodic Heating Method

Measurement of Microscopic Thermal Diffusivity Distribution for Ryugu Sample by Infrared Lock-in Periodic Heating Method

Lock-in thermographic measurement and model-based evaluation of effective thermal diffusivity to quantify early stage fatigue damage of CFRP

Geometrical Effect on Thermal Conductivity of Unidirectional Fiber-Reinforced Polymer Composite along Different In-plane Orientations

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