How to Improve an FEA Model: Proper Load Applications

In the previous two editions of ‘How to Improve an FEA Model’, we discussed how model simplification and proper mesh generation can help facilitate an improved finite element analysis (FEA).

In the third edition of the series we will discuss the importance of choosing accurate load applications as it relates to the real-world environment the object will likely encounter in its lifecycle.

Load Applications

Determining proper load applications is an extremely important step in an FEA. Load applications are the model inputs that the object is being tested for, such as a specific event like a thermal cycle, shock from a drop, vibration, or static flexure. Understanding the nuances of how to apply the loads are essential in order to simulate an event that the object will face in a real-world environment.

One common example is determining whether loads applied should be applied as static or transient. For example, if an engineer is simulating the flexure of a structure during assembly, it may be acceptable to model the load as a static displacement since strain rates are likely to be much slower and results time-independent. However, if an engineer is modeling a similar deflection caused by dropping the same assembly, they would likely need to use a transient model to capture the associated inertial effects, since the application time of the load is much faster and time-dependent effects must be captured.

In the electronics simulation world, we often deal with a similar case when simulating thermal cycling. For example, when investigating the thermal expansion and associated stresses on an entire printed circuit board assembly (PCBA) during thermal cycling, the material properties in the analysis can likely all be linear approximations, and static ramps to the minimum and maximum temperatures to investigate those stress states with no dependence on time can be reasonable. This is acceptable when board-level displacement and elastic stresses/strains are the focus of an analysis rather than creep strains/energies. However, when investigating component-level solder fatigue, solder creep properties must be included and it becomes important to accurately apply the ramp and dwell times of the thermal cycle. Creep models include time-dependent properties, so the simulated cycles must be modeled in their entirety to most accurately calculate creep strain/energy results that are used to make solder fatigue predictions.

The same real-world event is not always equal in the FEA world depending on the desired outcome of the analysis. It’s important to always keep in mind the real-world stressors the object will likely face and how those stressors could affect the component of interest. Inputting these nuances properly will result in an analysis that is accurate, valid, and actionable.

Learn more about the steps that can be taken to improve in an FEA model in the first and second edition of the “How to Improve an FEA Model” blog series.


Topic: reliability testing, finite element analysis, meshing

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How to Improve an FEA Model: Proper Mesh Generation

In the first edition of the “How to Improve an FEA Model” blog series, we discussed improving a finite element analysis (FEA) model using model simplification.

Topic: reliability testing, finite element analysis, meshing

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How to Improve an FEA Model: Model Simplification

Developing a successful and effective Finite Element Analysis (FEA) model can result in a frustrating experience for design engineers. The model needs to be simple and easy to replicate, while still complex enough to provide valid test results. This creates a problem where models are often either too simplified and approximated to provide accurate analysis, or the model is too complicated for easy processing.

Topic: reliability testing, finite element analysis, meshing

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Digital Image Correlation: What it is and Common Pitfalls

Digital Image Correlation (DIC) is a non-contact, full field displacement optical measurement technique.

It is most often used in the following applications:

  • Material characterization (CTE, glass transition temperature, Young’s Modulus, Poisson’s Ratio)
  • Sample testing – fatigue and failure (in situ monitoring of displacements and strains)
  • Applications where displacement or deformation measurements are needed
  • High speed/frequency applications (i.e. crash testing, vibration)
Topic: Electronics Design, electronics failure, printed circuit board

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Red Phosphorus and Electronic Failures

Picture: A connector that shows evidence of corrosion from red phosphorus.

Electronics manufacturing is a complicated business. Consumer demand, manufacturing supply chains, materials, and regulations are constantly changing. Every company wants to be the first to market with the newest, coolest, most profitable technology. But sometimes the rush to get to market leaves safety and reliability in the dust. Design review and thorough supply chain assessment help mitigate electronic failure risks before they happen. Unfortunately, we get to see the same mistakes being made over and over again.  

Topic: electronic failures, red phosphorus

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Using FEA to identify Microvias and PTHs at Risk of Failure

Plated through holes (PTH) and vias are structures that interconnect signal circuits at different PCB layers. They are typically categorized as through vias (or PTH), blind vias, and buried vias. Due to the higher I/O density and smaller electronic packages evolving in the past decades, the demand for high density interconnects has increased significantly.

Topic: Sherlock, plated through via, via reliability, microvias, plated through holes, finite element analysis

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Power Semiconductor Unique Capabilities in the New Use Environments

As the power consumption of data center applications has grown, power devices have found their way into products across different market segments such as information technology, electric motor drives, grid infrastructure, automotive, and aerospace. This resurgence of wide-bandgap devices is not only driving growth by enabling high volume manufacturing and reduction in cost, but also innovation in material and packaging technologies lead to improvement in reliability and novel device types.

Topic: Semiconductor reliability, integrated circuits, Wide-bandgap, power devices

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Why Flux Residue Can Cause Electronics Failures

We perform dozens of failure analyses every month for our clients in various industries and identify many different root causes of failure. One that can be difficult to identify and prove is soldering flux residue. As circuit designs shrink and become more complex, flux residues are more likely to cause failure from leakage current.

Topic: Failure Analysis, electronics failure, flux residue

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Power Supply Components And Thermal Stress

Power supply is the core of electronic equipment. But as crucial as it is, designing a power supply can be difficult due to an indirect feedback loop within design teams, especially when it comes to thermal solutions. It is often more difficult to know what the temperature should be as opposed to what the temperature will be.

Topic: Magnetic Components, Thermal Cycling, LED Failure Modes, temperature cycling, LED, Temperature, electronics failure, Solder Joint Fatigue, Thermal Failure, Sherlock Automated Design Analysis, solder joint, integrated circuits

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How the Battery Supply Chain is Changing

When our customers approach us about battery reliability, the most pressing question is always, “How do we prevent catastrophic battery failures?”  While the rate of field failures is statistically low at only 1 to 10 ppm, the impact of battery failures has often been severe in recent years. Higher energy densities, and the use of lithium ion batteries closer to the human body are to blame for the severity of impact.

Topic: Thermal Batteries, Battery Technology, Battery Reliability, Battery Safety, Battery Failure, Lithium Ion Battery, battery swelling, swollen battery, battery management system, lithium battery explosion, ion battery

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