Accelerated aging


Accelerated aging is testing that uses aggravated conditions of heat, humidity, oxygen, sunlight, vibration, etc. to speed up the normal aging processes of items. It is used to help determine the long-term effects of expected levels of stress within a shorter time, usually in a laboratory by controlled standard test methods. It is used to estimate the useful lifespan of a product or its shelf life when actual lifespan data is unavailable. This occurs with products that have not existed long enough to have gone through their useful lifespan: for example, a new type of car engine or a new polymer for replacement joints.
Physical testing or chemical testing is carried out by subjecting the product to
  • representative levels of stress for long time periods,
  • unusually high levels of stress used to accelerate the effects of natural aging, or
  • levels of stress that intentionally force failures.
Mechanical parts are run at very high speed, far in excess of what they would receive in normal usage. Polymers are often kept at elevated temperatures, in order to accelerate chemical breakdown. Environmental chambers are often used.
Also, the device or material under test can be exposed to rapid changes in temperature, humidity, pressure, strain, etc. For example, cycles of heat and cold can simulate the effect of day and night for a few hours or minutes.

Techniques and methods

Accelerated aging employs a variety of controlled methods to replicate and speed up the effects of natural aging. These methods vary depending on the type of product, material, or environmental condition being simulated. Below are the most commonly used techniques:

Environmental Stress testing

Temperature cycling

Samples are exposed to repeated cycles of extreme heat and cold, mimicking daily or seasonal temperature fluctuations. For example, in the automotive industry, components like engines and braking systems are tested using temperature cycling to simulate real-world conditions such as hot desert climates during the day and freezing temperatures at night. In electronics, printed circuit boards are subjected to rapid temperature shifts to evaluate solder joint reliability and material resilience.

Thermal shock

refers to the rapid exposure of materials or components to extreme temperature differences over a very short period. Unlike temperature cycling, which involves gradual changes between high and low temperatures, thermal shock imposes abrupt transitions that can lead to immediate stresses within a material. This method is often used to evaluate a product's resistance to cracking, warping, or other forms of failure caused by sudden thermal gradients. For example, glass or ceramic components in aerospace applications are subjected to thermal shock tests to ensure durability under high-speed atmospheric reentry conditions.
Thermal shock chambers are specialized devices that facilitate rapid temperature transitions to simulate extreme environmental conditions. These chambers typically consist of two or three zones with distinct temperature settings—high, low, and sometimes ambient. A product carrier basket automatically transports the test specimens between these zones, ensuring swift temperature changes.
BGA components are particularly susceptible to failures induced by thermal shock due to the mechanical stresses exerted on solder joints during rapid temperature changes. Research has shown that thermal shock can lead to the initiation and propagation of cracks within these solder joints, compromising the integrity and reliability of electronic assemblies.
The reliability of PCB assemblies often hinges on the durability of their solder joints. In harsh environments characterized by significant temperature variations, these joints are prone to crack formation and eventual fracture, underscoring the importance of rigorous thermal shock testing in the design and assessment of electronic components.
Beyond electronics, thermal shock testing is employed across various industries to assess the durability of materials and products subjected to rapid temperature changes. For example, in the automotive sector, components such as engine parts and safety equipment are tested to ensure they can withstand the thermal stresses encountered during operation. Similarly, "the aerospace industry uses environmental test chambers to test parts like avionics, satellite equipment, and airplane parts. These parts need to be able to handle extreme temperatures during launch, re-entry, and in space.

Humidity testing

Humidity testing involves subjecting materials or products to high levels of moisture or fluctuating humidity conditions to simulate exposure to tropical, coastal, or industrial environments. This method is used to evaluate the effects of moisture on material degradation, corrosion, swelling, and overall performance.
For example, electronic devices undergo humidity testing to ensure their enclosures and seals can prevent moisture ingress, while construction materials such as wood or adhesives are tested to evaluate resistance to warping or delamination.
Humidity testing is often conducted in combination with elevated temperatures to accelerate the effects of moisture exposure, particularly for materials like polymers, metals, and composites.

UV exposure

testing is a component of aging tests designed to simulate the long-term effects of ultraviolet radiation exposure on materials, products, and coatings. UV radiation, a component of sunlight, is one of the primary contributors to material degradation over time. UV testing helps assess the durability and performance of materials under prolonged exposure to UV light, providing insights into their expected lifespan and identifying potential vulnerabilities.

Oxygen and pollutant exposure

Samples are exposed to controlled concentrations of oxygen or atmospheric pollutants to simulate oxidative degradation or corrosion.

Salt spray test

, also known as salt fog testing, is a widely utilized method in environmental stress testing to assess the corrosion resistance of materials and surface coatings. By exposing specimens to a controlled saline environment, this accelerated aging test simulates the corrosive effects of marine and coastal conditions, providing valuable insights into a material's durability and longevity.

Dust testing

Dust testing is used to evaluate the resilience and performance of devices and systems exposed to particulate contaminants.
In gas distribution networks, dust contamination can originate from various sources, notably black powder. Hydrogen sulfide present in natural gas can react with metals, particularly copper, forming metal sulfides. Over time, these sulfides can flake off, creating fine black dust that poses risks to gas appliances and meters.
Gas meters are susceptible to contamination from these types of dust. The ingress of metal dust can lead to mechanical wear, blockages and corrosion.

Mechanical stress testing

Mechanical stress testing evaluates the durability of materials and components under repeated mechanical loads, simulating real-world conditions that may cause degradation over time. These tests help identify potential failures due to fatigue, wear, or structural weaknesses.

High-speed operation

High-speed operation tests assess how a material or device withstands prolonged exposure to rapid movement or mechanical cycling. This is commonly used in industries such as aerospace, automotive, and manufacturing, where components experience frequent high-speed motion. The test may include accelerated wear simulations, friction analysis, and thermal effects caused by rapid motion.

Vibration testing

Vibration testing simulates mechanical oscillations that a component may encounter during its lifespan. This method helps determine resistance to structural fatigue and mechanical resonance, which can lead to failure. Testing is performed using controlled vibration frequencies and amplitudes, often conducted with electrodynamic or hydraulic shakers. Industries such as electronics, transportation, and construction rely on vibration testing to improve product reliability and safety.

Chemical stability testing

Chemical stability testing evaluates the long-term resistance of materials and products to chemical degradation. This form of testing is crucial for determining how substances react to environmental factors such as heat, humidity, oxidation, and exposure to aggressive chemicals. It is widely used in industries such as pharmaceuticals, polymers, and coatings to ensure product reliability and safety.

Thermal aging

Thermal aging tests assess the effects of prolonged exposure to elevated temperatures on a material's chemical and physical properties. High temperatures can accelerate oxidation, polymer degradation, and phase transitions, leading to reduced mechanical strength and altered performance characteristics. These tests are commonly applied in the evaluation of plastics, rubber, lubricants, and electronic components.

Chemical exposure

Chemical exposure testing examines the effects of contact with reactive substances, such as acids, bases, solvents, and oxidizing agents, on material stability. These tests help predict corrosion, swelling, discoloration, and structural degradation that may occur over time. Industries such as pharmaceuticals, aerospace, and construction use chemical exposure testing to assess product durability under real-world conditions.

Combined stress testing

Combined stress testing evaluates the aging behavior of materials, components, and products under multiple simultaneous stress factors. Unlike single-factor aging tests that examine specific conditions, combined stress testing aims to replicate real-world conditions where multiple degradation mechanisms act together. This type of testing is essential for assessing long-term reliability, identifying failure modes, and improving product durability across industries such as aerospace, automotive, electronics, and pharmaceuticals.