This quantitative technique is applicable in the

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This quantitative technique is applicable in the field with commercially available acoustic emission instrumentation and software. 400 Acoustic Emission Testing
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Introduction Colin Chapman, the legendary car designer, once said that his car only had to make the checkered flag of that race — it should fail immediately after that. The material properties of the racing car are selected to maximize its speed and handling. An important feature of the racing car (Fig. 11) is the ratio of power to weight. There is a minimum weight limit, ordinarily as low as possible for the car, set by the international racing authority, the Federation Internationale de l’Automobile. The vehicle is required to weigh at least 600 kg (1300 lb). Designers of grand prix cars strive to find the minimum weight for racing. Grand prix teams desire parts as light as possible to allow for the largest possible mass of movable ballast. Weight has been considerably reduced by carbon fiber components in grand prix cars and these weight savings are used for the strategic placement of ballast. There is no limit on what proportion of the car’s weight may be ballast. The placement of the ballast affects the center of gravity, the position through which inertial forces act. The center of gravity is a primary performance measure, along with the tires, aerodynamics and engine power. Ballast is distributed as low as possible in the car and in the desired positions along the wheelbase to reduce the height of the center of gravity and so reduce vertical wheel loads during cornering. One must now assume that the driver can control the car at the limit of tire adhesion at all times. This reduction of weight transfer across the car from the lower center of gravity results in more grip for any given tire. In real terms, better grip allows for higher cornering speeds and therefore a reduction in lap time — the primary reason that minimum structural weight enhances performance. To that end, all structures are designed for minimum weight within the constraints of self-imposed stiffness targets and the safety regulations of the sport’s governing body. Among the technical regulations pertaining to driver safety are mandatory test procedures for the safety structures of the car, helping the driver to survive high impact forces. To avoid component failure during a race, many of the critical components of the car are proof tested between races. Acoustic emission testing can aid in the attainment of the lightest vehicle possible. Acoustic emission testing is a passive testing technique that can detect the damage mechanisms of carbon fiber structures under load. This technique can provide useful feedback to the designer to improve the design during proof testing. The following discussion illustrates the use of the felicity ratio as provided in the ASTM E 1067, Standard Practice for Acoustic Emission Examination of Fiberglass Reinforced Plastic Resin (FRP) Tanks and Vessels. 19 Structural Requirements Certification for Driver Safety
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  • Fall '19
  • The Land, Nondestructive testing, Acoustic Emission, Acoustic Emission Testing

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