Preventing Silent PCB Killers: How Multiphysics Simulation Unmasks Humidity-Driven Failures
Published: August 04, 2026
Preventing Silent PCB Killers: How Multiphysics Simulation Unmasks Humidity-Driven Failures
In the world of hardware development, thermal management often gets all the attention. Developers carefully calculate heat sinks, design intricate thermal vias, and select high-temperature components. Yet, there is a far more insidious threat waiting to compromise electronics in the field: humidity. While heat can degrade components over time, moisture can cause sudden, catastrophic failures that leave no visible trace of the root cause once the environment dries out.
With the rapid transition toward high-voltage systems—driven by electric vehicles, renewable energy infrastructure, high-density data centers, and advanced IoT deployments—the stakes of humidity-induced failure have never been higher. To combat this issue, researchers at the Centre for Electronic Corrosion (CELCORR) at the Technical University of Denmark (DTU) are pioneering the use of multiphysics simulation. By building accessible, parameter-driven simulation apps, they are bridging the gap between materials science and hardware engineering, allowing designers to proactively protect their circuits from environmental decay.
The Chemistry of PCB Failure: Electrochemical Migration
To understand why moisture is so destructive, we must look at the microscopic level. When an electronic device operates in a humid or fluctuating climate, condensation can form a microscopic water film on the surface of the printed circuit board (PCB). This ultra-thin electrolyte layer, often measuring only a few micrometers in thickness, sets the stage for a process known as Electrochemical Migration (ECM).
ECM occurs when three conditions are met simultaneously:
- A continuous film of moisture linking adjacent conductors.
- An electrical potential difference (voltage bias) between those conductors.
- The presence of soluble metal ions (typically copper or silver from the PCB traces).
Under these conditions, an electrolytic cell is formed. Metal atoms at the positively charged anode dissolve into the water film as ions. These ions migrate under the influence of the electric field toward the negatively charged cathode. Once they reach the cathode, they neutralize and deposit as solid metal. Over time, these deposits grow outward, forming microscopic, needle-like structures called dendrites.
When a dendrite spans the entire gap between the two conductors, it creates a sudden short circuit. This bridge can cause immediate system failure, initiate localized melting, or in high-voltage applications, spark a thermal runaway event leading to fire. The core challenge for engineers is that once the short circuit occurs, the high current often vaporizes the dendrite, and the moisture evaporates. When the device is opened for analysis in a dry lab, the evidence is gone, leaving half of all environmental field failures classified as "unidentified root causes."
Bridging Materials Science and Hardware Design
Traditional electronic design automation (EDA) tools excel at verifying signal integrity, impedance matching, and logical routing, but they are blind to the physical environments in which the hardware must operate. Physical prototyping and environmental chamber testing can catch some of these vulnerabilities, but these methods are slow, expensive, and can only test a limited number of variables late in the development cycle.
To solve this, the CELCORR research group turned to multiphysics modeling. By combining chemical reaction kinetics, fluid dynamics, and electrostatics inside COMSOL Multiphysics, the team created models capable of predicting how design changes affect a PCB's vulnerability to corrosion. This approach sits at the intersection of electrochemistry and electronics engineering, translating complex chemical behavior into actionable design metrics, such as electrochemical leak current.
Modeling the Variables of Condensation
The research team built a virtual test platform using a simplified PCB geometry featuring two oppositely biased electrodes covered by a thin water film. This setup allowed them to manipulate several critical parameters and observe their impact on performance:
- Trace Spacing (Pitch): Analyzing how the physical distance between high-voltage traces changes the electric field strength and the speed of dendrite growth.
- Water Film Thickness: Simulating varying levels of relative humidity and condensation, from microscopic droplets to continuous liquid layers.
- Water Conductivity: Accounting for environmental contaminants, such as salt spray in coastal installations or industrial atmospheric pollutants, which drastically increase the electrolyte's conductivity.
By computing the stray electrochemical leak current passing through the simulated water film, the software provides a clear indicator of whether a specific layout will fail under designated operating conditions. This quantitative data allows developers to adjust trace layouts, implement specific trace geometries, or determine where to apply protective conformal coatings before committing to physical manufacturing.
Empowering Engineers with Simulation Apps
While multiphysics models are incredibly powerful, they typically require specialized knowledge of chemical kinetics and finite element analysis (FEA) to run. To make these insights accessible to everyday hardware developers, CELCORR utilized the Application Builder to package their complex equations into intuitive, standalone simulation apps.
These apps offer a simplified interface where an engineer can plug in their design specs: voltage, track distance, anticipated water film thickness, and cathode geometry. The app then runs the complex physics under the hood and outputs clear, visual representations of current density distribution, leak currents, and field strengths. This plug-and-play capability allows hardware teams to quickly run "what-if" scenarios—such as assessing whether widening a track gap by 0.5 mm will sufficiently mitigate leak current in high-humidity environments.
The Path to Climate-Robust Hardware
As electronics continue to shrink while power densities increase, designing for climate robustness is no longer optional. The establishment of the Centre for Climate Robust Electronics Design (CRED) highlights the growing industry demand for research into high-power, high-voltage systems that can withstand harsh operating environments.
Whether you are designing a compact ESP32-based outdoor sensor, a heavy-duty robotics controller, or high-voltage EV battery management systems, understanding the relationship between moisture, voltage, and materials is key. By shifting environmental testing from physical test chambers to virtual multiphysics environments, developers can deliver robust, reliable electronics that truly stand up to the elements.
About EDATA SL
EDATA SL shares practical electronics, embedded systems, Arduino, ESP32, Raspberry Pi, IoT, repair guides, DIY projects and technical news for engineers, students and makers.
Original news rewritten with AI for educational purposes.
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