Browse Topic: Radiation

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Research on Photobiological Safety of Automotive Active Infrared Detection System2021-01-00724/6/2021
The automotive active infrared detection system is usually applied to the night driver assistance system or the diver attention monitoring system. However, the infrared light emitted by the active infrared detection system can cause damage to retina, cornea and eye crystals. This paper has studied the photobiological safety of the infrared light source used in the automotive active infrared detection system. Although it has been already have the general requirements of photobiological safety in international standards, there is not any requirements for automotive active infrared detection system. The range of the active infrared detection system depends on the radiation intensity of the infrared light source, but too much radiation intensity will cause harm to retina, cornea and eye lens when the infrared light source is too close to eyes. Based on the international standards, this paper has analyzed the retinal thermal hazard and the harm to skin and eyes caused by infrared radiation, and it has calculated the theoretical radiation intensity threshold under different risk groups and safety distances. The threshold of radiation intensity of the automotive active infrared detection system have been proposed, which could provide references for the formulation of Chinese national standard. What’s more, the experimental verification has been conducted by using the driver attention monitoring system, and the conclusion indicates that the threshold proposed in this paper is reasonable.
Hu, YueZhu, TongLi, QianYang, Xiong
Determining Vibro-Acoustic Characteristics and Structural Damping of an Elastic Monolithic Panel2019-01-15386/5/2019
Evaluations of the dynamic and acoustic responses of panels, partitions, and walls are of concern across many industries, from building home appliances, planning meeting rooms, to designing airplanes and passenger cars. Over the past few decades, search efforts for developing new methodologies and technologies to enable NVH engineers to acquire and correlate dynamically the relationship between input excitations and vibro-acoustic responses of arbitrary-shaped panels has grown exponentially. The application of a particular methodology or technology to the evaluation of a specific structure depends intimately on the goals and objectives of the NVH engineers and industries. In this work, we present the comparisons between the traditional modal analyses for structural vibrations together with sound intensity measurements of sound radiation and a laser-assisted Helmholtz equation least squares (HELS) method [1, 2, 3, 4] to characterize the dynamic and acoustic responses of an arbitrarily shaped structure subject to non-contact acoustic excitations. Input data for the latter include the normal surface velocities measured at a finite number of points on the surface of the structure that are accessible to a laser beam, and the acoustic pressures measured at a few points in the near field. With these input data, we will be able to reconstruct the normal surface velocity, the surface acoustic pressure, the normal surface acoustic intensity distributions over the entire structure, dimensionless structural damping ratio spectrum, sound transmission losses (STL), and sound transmission paths, etc. These data enable engineers to acquire a comprehensive understanding of the vibro-acoustic characteristics of any arbitrarily shaped vibrating structure, which can lead to the most cost-effective NVH reduction.
Figueroa, AntonioWu, SeanChen, Lingguang
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