Simulating the effects of stress factors in accelerated aging tests involves accurately replicating and enhancing environmental stresses such as temperature, humidity, light, mechanical stress, and chemical stress through laboratory equipment to induce performance degradation behaviors in products during long-term use in a short period. The following are mainstream and practical simulation methods, categorized by stress type:
1. Temperature Stress Simulation: Accelerating Thermal Aging and Fatigue
Accelerating failure processes such as material oxidation, polymer degradation, and interface delamination through high-temperature or temperature cycling environments.
High Temperature Storage Test (HTS)
Placing samples in a constant high-temperature environment (e.g., 85℃, 105℃, 150℃) to assess thermal stability.
Applicable to: Electronic components, plastics, rubber, batteries, etc.
Standard References: GB/T 3512, JESD22-A108
Temperature Cycling Test (TCT)
Repeatedly switching between extreme high and low temperatures (e.g., -65℃ ↔ +150℃) to simulate fatigue damage caused by thermal expansion and contraction.
Applicable to: PCB solder joints, packaging materials, automotive components.
Standard Reference: JESD22-A104 Key Control Parameters: Heating/cooling rate, residence time, cycle count.
2. Humidity Stress Simulation: Assessing the risk of moisture absorption and electrochemical failure. Accelerates hydrolysis reactions, metal corrosion, and insulation performance degradation in high humidity environments.
Constant Humidity and Heat Test: Continuous exposure under high temperature and humidity conditions (e.g., 85℃/85%RH) to examine the material's hygroscopicity and interface stability.
Applicable to: Electronic packaging, photovoltaic modules, medical packaging.
Standard Reference: IEC 60068-2-78
Alternating Humidity and Heat Test (THB/HAST)
THB: Temperature and humidity cycling + bias voltage, assessing the risk of electrochemical migration.
HAST (High Accelerated Temperature and Humidity Stress Test): 130℃/85%RH, high voltage acceleration, replacing traditional THB with a shorter cycle.
Applicable to: Semiconductor devices, high-density PCBs.
Standard Reference: JESD22-A101
Advantages: HAST can achieve the equivalent of 1000 hours of traditional THB testing in 96 hours.
3. Photo-Stress Simulation: Reproducing UV and Full-Spectrum Aging Effects
Utilizes artificial light sources to simulate ultraviolet, visible, and infrared radiation in sunlight to assess the light stability of materials.
Ultraviolet Aging Test (QUV)
Uses a UVA-340 fluorescent lamp to simulate the UV segment of sunlight (340nm), inducing polymer chain breakage, yellowing, and embrittlement.
Suitable for: Plastics, coatings, textiles.
Standard Reference: ASTM G154
Xenon Arc Aging Test
Uses a xenon arc lamp to simulate full-spectrum sunlight, including UV, visible, and infrared radiation, more realistically reproducing outdoor aging.
Spraying and dark cycles can be set to simulate day-night cycles and rainfall.
Suitable for: Automotive exteriors, building materials, outdoor advertising.
Standard Reference: ISO 4892-2
Key Indicators: Irradiance control (e.g., 0.76 W/m² @ 340 nm), blackboard temperature, spray cycle.
4. Chemical Stress Simulation: Assessing Corrosion and Media Resistance
Testing the corrosion resistance or solvent resistance of materials by exposing them to specific chemical environments.
Salt Spray Corrosion Test
Continuously spraying a 5% NaCl solution in a salt spray chamber to simulate metal corrosion in marine or coastal environments.
Suitable for: Metal housings, connectors, fasteners.
Standard Reference: ISO 9227
Ozone Aging Test
Placeing rubber products under a specific ozone concentration (e.g., 50 pphm) and observing surface cracking.
Suitable for: Sealing rings, tires, waterproof membranes.
Standard Reference: GB/T 7762
Chemical Media Resistance Test
Immersing materials in acids, alkalis, oils, and solvents and evaluating changes in quality and retention of mechanical properties.
Suitable for: Pipes, protective coatings, industrial containers.
5. Mechanical Stress Simulation: Verifying Vibration and Shock Resistance
Simulates dynamic loads during transportation and use through mechanical loading.
Random Vibration Testing
Applies multi-frequency vibrations according to PSD (Power Spectral Density) curves to simulate automotive or aerospace environments.
Suitable for: Automotive electronics, aerospace equipment.
Standard Reference: SAE J2534
Shock Testing
Applies high-g short-pulse impacts (e.g., 1000g, 0.5ms) to simulate drops or collisions.
Suitable for: Portable devices, military products.
Equipment Support: Electric vibration table, drop test machine.
6. Multi-Stress Coupling Simulation: Closely Resembling Realistic Complex Environments
In actual use, multiple stresses often act simultaneously, thus requiring the design of composite test schemes.
HALT (High Accelerated Life Testing)
Combines rapid temperature changes, multi-axis vibration, and voltage fluctuations to quickly expose design flaws.
Suitable for: Limit verification during new product development.
HASS (High Accelerated Stress Screening) applies high stress to products during the production phase to screen out early-failure samples.
Suitable for: High-reliability products in mass production.
Advantages: More efficient at identifying potential failure modes than single-stress testing.
Summary: The choice of simulation method depends on the product's usage scenario, material properties, and primary failure mechanisms. The ideal approach is to use single stress as a foundation and multiple stress couplings for verification, ensuring the testing is both scientifically sound and engineering-practical.
