1992 GM Ultralite Concept Car
I found a very interesting video demonstrating the 1992 GM Ultralite Concept Car. What a blast from the past!
This project, like all concept cars, was well before its time. They had some cutting-edge engineering that went into this vehicle to work towards several goals.
Reducing vehicle weight was important, so carbon fiber materials were utilized to decrease the weight of the body/chassis. Efficient drive-train options were also developed, including the use of two-cycle engines and battery power. Designing for great aerodynamics was also considered.
Many years have passed by, and some things were right on, some were not. Aerodynamics have been improved. Lighter weight materials have been used as composites have been working their way into vehicles, though it has been SMC/BMC reinforced with Fiberglass rather than Carbon Fiber.
Gull-wing doors have not been adopted for family cars, and I am not sure if I am disappointed or not.
Carbon Fiber Repair Panel
I found a great video demonstrating the repair of a carbon fiber composite panel. The is is a carbon fiber reinforce epoxy structure that needs a localized repair to the core material. This repair uses a vacuum bagging process to help maintain a high-quality laminate.
The video is sped up to quickly demonstrate the overall process required. This process requires a high level of attention to details, as they are very important. Training and experience are necessary for good results.
Chemical adhesion between all of these layers will create a bond that is durable and suitable for restoring strength back to the structure.
Composite Guitar Cases
Not being a musician, I had not been familiar with instrument cases, specifically for guitars. Many of them are made of composite materials, both fiberglass and carbon fiber.
The advantages of composites align well with requirements for handling musical instruments. Composites are strong and lightweight, as well as impact resistant. Composites are also not affected by moisture.
I came across an interesting video by WallyUpdabungenstein who does a comparison of a Calton deluxe fiberglass guitar case as compared to a Hoffee carbon fiber guitar case.
He does a great job comparing the actual fit and handling of the guitar in the case. He does not discuss the construction materials of the cases, but does look at the important aspects of them. Any item that is intended for a primary purpose such as protecting musical instruments needs to do a good job at this primary purpose.
Auto Racing Composites
Roush Racing takes us viewers on a tour through their composites shop in a short clip from Roush TV.
Using mostly carbon fiber and kevlar reinforcements, Roush Racing fabricates many different components for the racing industry using epoxy resin systems. Ranging from the front noses for the NASCAR Car of Tomorrow car to drag racecar bodies and small ductwork, Roush Racing’s composites shop does all sorts of fabrication.
The race shop includes two different fabrication processes. Wet layup vacuum bagging is used for some parts, while others are made using prepreg material that goes into an autoclave.
The video tour is well done, and includes everything from the Eastman material cutter to the fabrication process, bagging process, and trim. We also get to see some of the finished parts after they are demolded and trimmed.
These parts are very expensive to manufacture, due to the high cost of materials and labor. Tooling and equipment costs for this type of process are somewhat reasonable, with the exception of the autoclave and the automated cutting table. Composites fabrication of this caliber is labor intensive, but can produce very unique parts that are lightweight and strong.
Non-Destructive Testing with Ultrasound
Composite materials can become damaged in many different ways. There can also be flaws in the original manufacturing process. Many times it is necessary to identify any damaged areas within the composites layers that cannot be detected with the eye.
Inspection of composites fiberglass and carbon fiber structures may be required for advanced critical applications of composites materials. Identifying any potential problems with the composites structure is extremely important.
Of course problems can be identified through destructive testing-drilling holes, making cuts, etc. It also may be necessary to do testing in a non-destructive manner, i.e. not cutting into the laminate that is being tested.
One method of accomplishing non-destructive testing of composites laminates is using ultrasound. This Youtube video demonstrates the use of this method.
As you can see, the damage is found in this carbon fiber laminate. This information is a flag that can be used to decide whether to make a repair or replace the structure.
Delamination within the fiberglass or carbon fiber part will result in a much weaker structure than the design intended. Other areas of the composites part will be further strained by weaknesses in other areas and may also fail.
This ultrasonic test can help to identify otherwise invisible problems with either the original manufacturing process or damage during the life cycle of the composite part.
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