Cartridge-actuated devices (CADs) and propellant-actuated devices (PADs) are critical components in diverse aerospace and military equipment and heavy machinery applications. These safety devices create various controlled explosions to power the device’s action and help ensure fast and reliable emergency responses.
To assure the safety and reliability of CAD and PADs, experts conduct environmental testing to assess their performance in different settings. Environmental testing can help prevent risks from environmental factors like humidity, temperature variations and vibration.
Importance of Environmental Testing
CADs and PADs are essential in many mission-critical or emergency operations, and environmental testing helps ensure they perform. Some reasons environmental testing is so important include:
- Safety assurance: Environmental testing helps identify potential vulnerabilities in CADs and PADs that could lead to malfunctions or problems during real-life scenarios. When subjecting these pyrotechnics to various environmental conditions, including pressure and temperature extremes, professionals can better assess how they operate to implement necessary modifications and ensure safe operations. Dependable performance is especially important during emergency situations.
- Regulatory compliance: Many industries, including aerospace and defense, enforce strict regulations and standards that require PADs and CADs to undergo environmental testing to meet safety and performance compliance standards. Testing ensures these devices meet industry standards and compliance requirements for reliability and durability.
- Cost-effectiveness: Environmental testing can save costs by preventing failure and downtime for CADs and PADs. By identifying potential issues early, operators can address them before they become larger problems requiring more expensive repairs or replacements.
- Reliability enhancement: Testing CADs and PADs in different environmental conditions helps engineers identify vulnerabilities and take preventive measures to enhance reliability. Subjecting the devices to real-life situations can give users more confidence in a CAD or PAD’s ability to withstand demands and ensure they function as needed in critical situations.
CADs and PADs undergo rigorous routine check-ups and periodic replacements to avoid safety issues and ensure optimal performance and reliability.
Environmental Factors Impacting CAD and PAD Performance
Without proper testing and design strategies, the following environmental factors can impact CAD and PAD performance:
- Temperature variations: Extreme temperatures can impact CADs and PADs, causing parts to expand or contract and potentially affecting performance.
- Humidity levels: High humidity levels can corrode and oxidize metallic components in CADs and PADs, affecting their structural integrity and electrical connections. These changes can impact reliability and lead to safety hazards during operation.
- Vibration and shock: Vibrations and shocks can impact CADs and PADs, affecting alignment, connections and functionality. These problems can lead to premature wear and loose components.
- Altitude and pressure: Changes in pressure and altitude can impact the combustion characteristics of propellants used in PADs, altering their performance and impacting accuracy and reliability.
- Chemical exposure: Exposure to chemicals, lubricants, cleaning agents and fuels can degrade the materials and seals of PADs and CADs, leading to degradation, loss of seal integrity and potential leaks.
Understanding how environmental factors impact CADs and PADs through testing is critical to making modifications and ensuring optimal performance, safety and reliability.
Testing Methods and Protocols for CADs and PADs
Subjecting CADs and PADs to environmental stressors can help manufacturers identify potential issues and make modifications to ensure optimal performance, safety and reliability. Testing methods and protocols for CADs and PADs can address the following areas:
Extreme Temperature Tests
In an extreme temperature test, CADs and PADs are exposed to very high and low temperatures in environmental chambers to simulate real-world conditions. Some examples include:
- Gradual temperature changes.
- Rapid thermal cycling.
- Freeze-thaw cycles.
- Thermal shock.
- High and low ambient temperatures.
These situations can lead to a vast range of problems, from making materials expand or shrink to changing the burn rates of explosives and propellants. After performing the testing procedure, testers evaluate its effects on the CAD/PAD’s performance in areas like thrust, pressure, displacement, velocity and acceleration.
Drop and Impact Tests
In a drop test, the tester drops a CAD/PAD from specific heights onto hard surfaces. Some tests allow the device to have a transit case. These processes simulate impacts a device might see during regular operation or handling, such as loading onto a vehicle. After the test, experts assess characteristics like structural integrity and functionality and look for signs of damage.
MIL-STD-810 covers these shock testing procedures for defense applications, and you can find drop test standards for aviation in RTCA DO-160. Many other industries reference these standards, too.
Vibration Tests
Vibration testing methods involve mounting CADs and PADs on a table or shaker designed to create controlled vibrations. The devices are then subjected to vibration frequencies and amplitudes, simulating the environmental stressors encountered during transportation, operation or deployment.
The response of these devices to vibrational stress will determine their ability to withstand mechanical shocks and vibrations. Following the test, testers examine the CADs and PADs for signs of damage.
High-Altitude Tests
For high-altitude testing, CADs and PADs enter an altitude chamber where air pressure and oxygen are adjusted to simulate high-altitude conditions. Experts then observe how the devices operate in low-pressure environments to ensure reliability in high-altitude applications. Testers typically assess qualities like:
- Functionality
- Combustion efficiency
- Response to reduced atmospheric pressure
Moisture-Related Tests
Without proper design, fluid contact could cause various problems in a CAD/PAD. The pyrotechnic reactions rely on components that are usually hermetically sealed to prevent problems from fluids. For example, rainwater could cause electrical failure, while condensation might cause corrosion to internal parts. Testing procedures often review chemical, electrical and physical impacts, such as freezing or fungal growth.
Some types of tests to assess moisture effects on CAD/PAD products include:
- Fluid susceptibility and contamination: Fluid contamination tests can assess many substances, including rainwater, oil, fuel, solvents and cleaning compounds.
- Waterproofness: Testers can evaluate ingress protection with tests for immersion, rain and related topics. Along with fluid contact, rain could cause erosion and interfere with some systems, such as radio communication.
- Humidity: Humidity tests explore effects like potential electrical issues and corrosion.
- Salt fog and spray: Devices for coastal environments may also need salt tests to ensure resistance to the effects of salt deposits from ocean spray.
Contact AETC for Safe and Reliable Cartridge- and Propellant-Actuated Devices
Environmental testing is critical to maintaining the safety and reliability of CADs and PADs for aircraft owners and operators. At AETC, we put quality first. Our team has over a century of combined experience, and we channel that expertise into making safe products that adhere to military specifications and provide the foundation for life-saving devices.
Our CAD and PAD products include initiators, cutters, detonators and fire extinguishers to suit the needs of various items. Browse our products today, or contact us to learn more. We look forward to helping you find the right device for your application.
