The ability of these electronic systems to function reliably is becoming a greater aspect of vehicle safety that was dramatically demonstrated by the recall of over 9 million Toyota vehicles for unintended acceleration issues. While electronic reliability issues were widely suspected but eventually ruled out as a root cause, the crisis revealed the challenges of evaluating, validating and investigating the reliability and safety assurance aspect of modern, distributed and interactive vehicle controls systems that are equally taxing on OEMs, electronic system suppliers and regulators.
As an aftermath of the incident, the U. Meanwhile, in Europe the new standard ISO "Road Vehicles -- Functional safety" defines an automotive-specific approach for determining risk classes and requirements for validation and confirmation measures to ensure a sufficient and acceptable level of safety and reliability is being achieved.
There is now a new set of Computer Aided Engineering CAE tools that can help evaluate the safety and reliability of vehicular electronics models to meet these needs and support the new ISO standard. CAE modeling and simulation tools are now widely viewed as an automotive engineering core competency.
Henkel Adhesives Solutions for Electronics
It is needed to reduce new product development time, in order to get products to the market faster, at lower costs by helping to design them right on the first attempt. In the mechanical, civil and structural engineering fields the use of CAE structural analysis tools for optimizing performance, durability and reliability requirements are a standard part of the engineering process.
For automotive bodies, frame, suspensions, engines and all other structural elements, structural analysis is an essential procedure for verifying that usage condition stresses do not exceed the capabilities or fatigue limits of the material used in a product. By helping to design products and parts right on the first attempt, CAE analysis tools accelerate and improve the engineering process while reducing the need for physical prototype and durability testing which significantly reduces product development time and costs.
The primary issues being evaluated are overstress and wearout-related failures.
Using PCB Stress Test Analysis to Ensure Device Reliability
In items that are well designed for the loads in their application, overstress failures are rare and random. They occur only under conditions that are beyond the design intent of the device, such as acts of god or war, such as being struck by lightning or submerged in a flood. Overstress failures can be correlated to the traditional reliability concept of random failures. Load-stress analysis is used to determine if the strength limits of a design for stresses like mechanical shock events are adequate. Wearout failures are related to gradual stress driven damage accumulation of materials over time.
This covers failure mechanisms such as fatigue. By contrast, Electrical and Electronic EE engineers historically have gravitated to CAE tools for circuit, functional and software analysis with less emphasis on structural analysis tools that were viewed as less essential to their field.
However, as advancements in electronic technology have produced smaller and smaller devices that handle ever increasing amounts of power and heat, the micro structural integrity of wire bonds, micro-terminals and solder joints becomes increasingly important especially in the auto industry where the ability to endure years of harsh environmental conditions is needed.
This is underscored by the fact that the majority of field failures of electronic modules are physical and structural in nature, related to items such as thermal over stress and fracture or fatigue of wires, solder joints, component terminals, wire bonds, circuit board through-hole vias and such. Evaluating and achieving the structural integrity, durability and reliability of automotive electronic modules primarily remained dependent on traditional Design-Build-Test-Fix D-B-T-F reliability growth processes that employ a variety of environmental stress and usage durability testing of physical prototypes.
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The time and cost of building and testing prototype electronic components has been a limiting factor in efforts to accelerate the product development-validation process of automotive electronics. The conversion to hybrid and electric vehicle bring with it even greater increase in electronic content. For example, the Chevy Volt Lithium Ion battery module requires seven circuit board assemblies for battery system management and safety.
Each of these assemblies was required to be tested in accordance with an extensive durability profile.
This new CAE program is called Sherlock Automated Design Analysis ADA for its ability to investigate a design and identify if it is susceptible to failure mechanisms related to the intended usage environment of the application. The program works by performing a durability simulation in a virtual environment and calculating the durability life and reliability distribution of various failure mechanisms for the electronic component and structural elements on the circuit board s of an electronic module.
This is similar to the way structural durability analysis is now performed for vehicle body, chassis and other mechanical systems and parts. Sign In. Advanced Search. Article Navigation. Close mobile search navigation Article navigation. Volume , Issue 4. Next Article.
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