Long-term exposure of automobiles to outdoor environments leads to accelerated aging of exterior coatings, interior leather, and components of the three-electricity systems due to the coupled effects of natural light and temperature and humidity, which directly affects the vehicle’s appearance durability and functional safety. By precisely replicating the solar spectrum, solar simulators can shorten the aging test cycle to a few months or even days, making it a core technology in automotive material research and quality control. This article by Zicrean Measurement and Control Yingfeng will systematically analyze the principles, international industry standards, and typical application scenarios of solar simulators in automotive aging tests. The Impact of Natural Light on Automotive Materials Yingfeng The aging process of automotive materials under natural light depends on the nature of the light, radiation intensity, and material properties. Sunlight radiation, through the synergistic effects of factors such as radiation illuminance, environmental temperature, and humidity, triggers photo-oxidative degradation and thermal aging on the material surface, leading to performance degradation of automotive structural components and a decline in assembly stability. The multi-band characteristics of the solar radiation spectrum determine its complex interaction mechanism with automotive materials, among which ultraviolet (UV) radiation, thermal radiation, and visible light radiation are the main influencing factors.
Ultraviolet rays (10 – 400 nm) cause material deterioration by damaging the polymer molecular chains: UV-A (400 – 320 nm) leads to the degradation of specific high-molecular materials, UV-B (320 – 280 nm) has a strong degrading effect on most polymers, while UV-C (280 – 200 nm) has a weak impact in the natural environment due to atmospheric absorption. ■ Thermal radiation affects materials through the absorption and accumulation of their thermal energy. Under high-temperature conditions, it is prone to cause thermal stress cracking and reduced dimensional stability of plastics, rubber, etc., accelerating the breakage of polymer chains and oxidation reactions. ■ Visible light radiation mainly acts on components through the thermal energy conversion mechanism. Its degree of influence is closely related to light intensity, material thermal conductivity, and surface treatment methods, and ultimately exacerbates the aging process of the materials through the thermal accumulation effect.
The principle of automotive aging testing using a solar simulator
The solar light simulator precisely replicates the solar spectrum (especially the ultraviolet band), combined with temperature and humidity control and spray system, to simulate the aging process of automotive materials when exposed to the outdoors for a long time. Its core mechanisms include: Photochemical reaction: Ultraviolet light (290-400nm) causes the breakage or cross-linking of material molecular chains, resulting in color changes and degradation of mechanical properties. Thermal effect: High temperature accelerates the thermal expansion and degradation of materials, such as plastic brittleness and coating cracking. Wet heat synergy: High humidity environment promotes hydrolysis reactions, intensifying metal corrosion and swelling of high-molecular materials.
Solar light simulator ISO standard: Yingfeng led
ISO 877: Method for direct exposure of plastics to Fresnel concentrated solar radiation and solar exposure test.
ISO 16750-4: Image distortion rate of vehicle-mounted cameras after wet heat aging ≤ 0.3%. Solar light simulator ASTM standard:Yingfeng ASTM G 90: Outdoor accelerated aging using concentrated natural solar light. ASTM E 903: Measuring the solar light absorption and reflection rates of materials using an integrating sphere.
The molecular structure of automotive materials changes under the action of ultraviolet light
1. Exterior materials: For the bumpers and vehicle coatings, the color retention and adhesion were evaluated through xenon lamp aging tests, and they needed to meet ΔE ≤ 2.0 (ISO 105-B02). For the glass and headlight covers, the light transmittance attenuation and yellowing index (YI) were tested after ultraviolet irradiation. 2. Interior components: For the seat leather, the AI light control scheme shortened the test period from 45 days to 72 hours, and the aging effect matched the natural exposure with a coincidence rate of over 92%. For the dashboard plastic, the combination of temperature and humidity cycling (-40°C to 80°C) and vibration tests was used to verify the material’s fatigue resistance. 3. New energy powertrain system: Battery pack: The -40°C to 150°C temperature variation shock + humidity 95% RH combined test ensured the IP69K protection level. Electronic control module: After 85°C/85% RH humid heat aging, it needed to pass the ISO 26262 functional safety certification. The automotive aging test technology of the solar simulator simulates the natural environment to accelerate material deterioration, providing scientific and efficient quality verification methods for automotive manufacturers. With the breakthroughs in LED light sources, AI algorithms, and multi-factor coupling technologies, the test accuracy and efficiency have significantly improved, while costs and energy consumption have been significantly reduced. In the future, the solar simulator technology will further develop towards digitalization and intelligence, further supporting material innovation and reliability improvement in the automotive field.