Dr. Martin Crimp
Professor of Chemical Engineering
and Materials Science
Amir Mirtaleb
Graduate Teaching Assistant
Course Description
MSE 466 is a senior level course for Materials Science and Engineering majors that provides students with a team-based capstone design experience. A major aspect of this course is having the students apply their course-learned background knowledge and critical thinking skills in materials science and other disciplines to real-life material/component failure problems. Such failures are a major motivating factor for promoting more innovative designs or design changes. A failure analysis investigation provides a unique platform to design and solve real-world engineering problems via a systematic engineering approach. By focusing on specific component failures, the student teams learn how to confront open-ended problems that require them to develop a strategic design plan and to execute the methodology for assessing how and why the failure occurred. These open-ended studies are conducted using established investigative procedures and constraints for carrying out failure analysis. This semester, there are four 3-member teams carrying out investigations on real material/component failures.
Team Name: The Hammerheads
Project Name: Failure Analysis and Metallography of a Claw Hammer
Time: 8:00-8:40 a.m.
Many tools being used within industrial and at-home settings are expected to tolerate extreme compressive, tensile, or bending forces. Hammers typically withstand a user’s lifetime, and it is rare that one would fail within normal operation. Nevertheless, the face of a claw hammer, in the neck transition region, exhibited a complete fracture. The make and model of the hammer was unknown, but the fracture surface and knowledge of common processing techniques of hammers indicate that it was hot forged. Visual and metallographic observations of the fracture surface were utilized to analyze the failure. Stereomicroscopy, scanning electron microscopy/energy dispersive spectroscopy, Rockwell hardness, and Vickers microhardness were conducted to assess the potential root cause of the fracture. A chemical analysis by optical emission spectroscopy by a third party provided additional insight into the material behavior for further evidence of how the hammer fractured.
Team Name: ConRod Hall
Project Name: Examining the Failure of a Hyundai Genesis Connecting Rod
Time: 8:40-9:20 a.m.
Connecting rods (con rods) are a key part in an internal combustion engine, transmitting the energy from the combustion chamber to the rest of the drivetrain by linking the piston head to the crankshaft. The connecting rod from a 2015 Hyundai Genesis Coupe failed at 60,000 miles while in use and a complete fracture occurred near the base of the neck at the crankshaft connection. Various microscopy techniques, such as stereomicroscopy and scanning electron microscopy were used to analyze the fracture surface, specifically to differentiate primary and secondary damage on the rod. The additional use of chemical analysis and various material characterization methods led to an in-depth understanding of why the part failed.
Team Name: Veggie Tales
Project Name: Failure Analysis of Commercial Food Prep Blades
Time: 9:20-10:00 a.m.
Stainless steel is widely used in food preparation equipment due to its excellent corrosion resistance, strength, and durability. The Easy Chopper 2, a tough commercial food prep tool, uses 301 full hard stainless-steel blades to chop and dice ingredients. In a restaurant kitchen setting however, two adjacent top blades of the chopper fractured during normal use – posing a potential food safety hazard. To determine the cause of failure of the blades, a comprehensive failure analysis was performed utilizing a variety of experimental methods and techniques. The fracture surfaces were analyzed using optical microscopy and scanning electron microscopy (SEM) to document fracture morphology, potential crack initiation sites, and potential failure modes. Chemical composition analysis was conducted to validate the composition of the blades, while hardness testing was used to verify conformance to the material specifications of 39-45 Rockwell C. Metallographic examination was conducted to analyze the microstructure for signs of defects or any material discrepancies. The data collected from the materials characterization methods provided insight into the failure mechanism of the blades to determine the details surrounding the failure event. Understanding the failure mechanisms involved with the blades led to a better understanding of what engineering methods can be used to prevent failures like this from occurring in the future, minimizing risks to human health and economic waste.
Team Name: MowTown Breakdown
Project Name: Failure Analysis of Fractured Lawnmower Blades
Time: 10:00-10:40 a.m.
When doing any form of landscaping, in this case cutting the grass, failure of equipment leads to frustration, lost time, and in some cases personal injury. Having equipment similarly fail several times could be an indication of poor manufacturing, a quality control issue, or misuse by the operator. In this case, a Troy Bilt zero-turn tractor lawn mower had three blades that failed on the mower while in use. In this project, a variety of non-destructive and destructive testing methods were utilized to determine a possible cause for the failures. This process began with documenting the failed blades, primarily done with macrophotography and stereomicroscopy. From there, the blades were then sectioned for easier handling and observing. After careful consideration, some sections were cleaned and reimaged to view the fracture surfaces more effectively. Following cleaning, various hardness tests, as well as dye penetrant tests, were performed. In addition, sections of the blades were used to conduct tensile and Charpy impact tests. With the remaining material, microstructure analysis and scanning electron microscopy were utilized to form a more complete picture of the material and failure of the blades.
