Failure Analysis and Testing of Automotive Components

  • 12 May 2020

Failure Analysis and Testing of Automotive Components
Because of its intricacy, we continue with the theme for the Automotive industry. In the second article, we will expand your understanding of why it is not enough to focus only on testing the software, but that of many more aspects.

In my first article, I gave an example of a family trapped in an out of control vehicle, which was a case with a favorable outcome, and pointed out why testing in automotive industries is so crucial. In most cases, all eyes will be pointed towards software failure, but it`s not that easy.

“Software is not always the Bad Guy!“ - We will talk about why software fails, but this time the mistake is not its fault.
The automotive industry constantly faces new challenges, as the demand for inexpensive and high-quality components increases. Extreme diligence must be imparted to ensure that such components are designed and manufactured with sufficient quality to withstand a variety of service environments and provide maximum safety towards the user. In a situation in which such a component fails, it is important that the root cause of the failure can be determined quickly and accurately and that proper corrective measures can be taken in order to prevent future failures. A systematic analysis and tests are the keys to finding the root cause of any failure.

This article will describe some of the necessary steps for performing a proper failure investigation and will illustrate the use of various test techniques to identify the root cause of the component failure. The physical signs of failure, such as a cracked metal component or a malfunctioning electronic device, are the most obvious. However, these signs are often little more than symptoms of failure.

Potential causes of a device failure may include:

  • Product design
  • Manufacturing processes
  • Contamination of the source materials
  • Product packaging
  • Product storage
  • Improper handling
  • Improper installation
  • Improper calibration
  • Vibration
  • Temperature
  • Radiation
  • Extreme operating environment
First and foremost, we have to locate the problematic component, and then we have to divide our process into two main groups: Data Collection and Failure Analysis Tests.

Data Collection
The first step in failure analysis is data collection. During this step, all information about how the device failed and when it occurred will be collected. Additional steps are used to determine producer goals for the failure analysis examination, determine how the part should operate, and consult with additional experts if needed.

Collected Data Analysis
The next step in the failure analysis process is to determine the cause of the failure. Component failure is rarely the result of a single incident. The industry has shown there are multiple condition inputs into even a “simple” failure, including different variables and environmental conditions. The importance of this step is that all collected data indicates there are often different ways to prevent failure in the future.

Determining Corrective Actions
After receiving the report on both the causes and effects of component failure, determining certain corrective actions is the most important part of failure analysis for the manufacturer, including recommendations and procedures for the correction of said problems.

Recommendations for correcting a problem are both small and large changes that can have a significant impact on component quality:

  • Small changes in how source materials and product components are tested, treated, and stored can significantly reduce device failure.
  • Large changes such as Material defects like Metal, Plastic, or Composite structural material failure can produce significant economic costs for the manufacturer to replace or fix the problematic component.
Failure Analysis Tests
After actions of Data Collecting, Analyzing, and Correcting are determined, the logical course of events brings us to the following questions, How do we need to test it? & What is it that we need to test?

How do we need to test it?
After failure analysis, we can perform a variety of tests to determine the true source of a component failure (Component Testing Process). These tests are divided into two categories:

  • NDA: non-destructive tests, which keep a component intact.
  • DPA: destructive tests, which require the component to be altered in order to examine internal deviations, internal aberrations, cross-sections, or thermal behavior.

Test Description Type NDA:

  • Visual Examination Non-Destructive
  • Optical Microscopy Non-Destructive
  • Scanning Acoustic Microscopy Non-Destructive
  • 2D / 3D X-Ray Radiography Non-Destructive
  • X-Ray Fluorescence Spectroscopy Non-Destructive
  • Curve Trace / Electrical Inspection Non-Destructive
  • Contamination Analysis Non-Destructive

Test Description Type DPA:

  • Thermal Analysis Destructive
  • Destructive Physical Analysis (DPA) Destructive
  • Cross-section Analysis Destructive
*Source and example Table used by NTS Lab.

What is it that we need to test?
Today most of the automotive components are electronics (EC), printed circuit boards (PCB), or electronic devices (ED). Our focus here is on critical points of the components and parts of the components which can be labeled as possible critical points in future exploitation, such as areas of possible short-circuit, connectors/jack, production materials, etc.

PCB Failure Analysis Tests
There is a variety of different tests for printed circuit boards (PCB`s) which can be performed in order to examine the single-sided, double-sided, multi-layered circuit boards, flex, and high frequency/PTFE boards, including buries and blind via holes structures.

Tests for PCB failure:

  • Cross-section analysis
  • Solderability testing
  • PCB contamination testing
  • X-ray Inspection
EC Failure Analysis Tests
Electronic components and hardware failure can occur during many phases of a product’s life cycle. Along with problems during the product design and manufacturing stage, electronic components can fail because of issues with:

  • Storage
  • Packaging
  • Installation
  • Operation
  • Maintenance
Both non-destructive and destructive tests are performed to determine the cause of electronic component failures, a wide variety of tools and software are also used to recommend the right test techniques for the failed component.
Failure analysis tests of electronic components often use signal generators, sniffers, and vector signal analyzers. Microscopic, X-ray, and contamination analysis where necessary. Testers can also test for hardware failure during installation and operation, using a variety of programming languages and operating platforms.

ED Failure Analysis Tests
The testing of electronic device failure is often more difficult than determining the root cause of failure for other objects. Interactions between software and hardware require both skilled electronic and software experienced personnel.
ED tests in C/C++, Java, and Python, among other languages, are most common. Also use a wide range of electrical device tools such as IBM Rational Robot, Borland Silk Test, etc. which are parts of today`s testing standards.

Metal Failure Analysis Tests
Metal material and structural failure can have a big impact on component failure. From contamination and corrosion that causes equipment to fail to stress failures that affect structural integrity, metal failure can have major consequences. It’s estimated that metal corrosion alone accounts for nearly 40% of all problems occurred in component failure.

Metal Failure Analysis Tests are complex processes that rely on a variety of techniques. Data acquisition tools help us determine the cause of metal failure quickly and also help us determine solutions to fix the problem. Regularly performed tests besides corrosion studies include impact tests and fatigue testing on metal components.

Plastic - Composite Failure Analysis Tests
Plastics can be problematic and cause many major failures of components in many different ways. Plastic products can fail from stress fractures, fatigue, material degradation, and contamination. Plastic products can also fail in less-serious ways: discoloration and distortion can both affect the integrity of plastic products. Locating the exact cause of plastic component failure requires a range of tests and an intense knowledge of polymers products.

Testing plastic components follows a basic and similar process used for metal failure analysis testing. Plastic failure analysis tests are more complex because plastic components often contain additives like plasticizers, colorants, and reinforcing fillers. As a result, failure testing for plastic components often requires specialized testing of the molecular and chemical structures in plastics. Microscopic and spectroscopic analysis is the most common test techniques used for plastic component tests.

Contamination Analysis Tests
Identifying contaminants in failed components can be a time-consuming process that requires major resources.
Contamination is not only tightly connected with the physical presence of foreign elements in inspected components, but contamination in some cases can also be related to outside or environmental influence, such as magnetic radiation, the influence of another component frequency, etc.

Types of contamination analysis tests:

  • Identifying the type of contamination
  • Identifying the area in which the contaminated component is operating
  • Identifying the type and source of foreign particles in a component
  • Determining the level at which a contaminant affects the component’s integrity
  • Tracing the source of contamination
I will finish this article with this message: “Testing is a process. In some cases, it behaves like a living organism. It is a chain of connected techniques including a variety of variables and a specter of knowledge which have to be performed together, and only in that case testing can justify its own existence and live.”

Author: Lazar Lazic
/Director Of Operations at Quality House Serbia/

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