Lightweighting Design Challenges
Lightweighting a vehicle is the process of developing and implementing new materials and optimizing a design to have less weight. Ultimately, the goal of lightweighting is to decrease the weight of the vehicle in order to reduce fuel consumption. This is driven primarily by new fuel efficiency requirements such as the 2025 Corporate Average Fuel Economy Standards requiring automakers to raise the average fuel efficiency of new vehicles to 54.5 miles per gallon (MPG) by 2025. While this does not mean each vehicle coming off the line must achieve 54.5 MPG, this type of legislation poses significant design challenges to automakers. In “Identifying Real World Barriers to Implementing Lightweighting Technologies and Challenges in Estimating the Increase in Costs,” the Center for Automotive Research (CAR), identifies the following lightweighting design challenges:
- Time and development to qualify new materials, develop models, and derive product specifications
- Manufacturers are increasingly using common parts across models making it difficult to optimize each model.
- The manufacturing infrastructure often doesn’t support new materials.
- Consumer demands drive additional “comfort features” such as better ride handling, less noise and less vibration. Each of these features require adding additional weight to the vehicle design.
- Organizations’ resources are significantly cost and time constrained, making exploring design alternatives challenging in each development cycle.
- Engineers must design to accommodate new regulations while maintaining a high degree of safety. This can significantly increase the amount of time needed to develop new materials for automotive designs.
Although fiber optic sensing cannot address all of these issues, it can help reduce the amount of time it takes to test and characterize new materials.
According to CAR, the development timeline for new materials is as follows:
- 3 to 6 months: procure materials for test.
- 6 months: preliminary characterization of materials: mechanical and strength tests, joining studies, microstructure analysis
- 12 to 18 months: detailed characterization of materials, strain rate behavior, fracture testing, formability analysis, reliability/fatigue testing, environmental durability
- 12 to 18 months: production readiness analysis. Validate CAE models, repair capability strategies, develop material specifications, identify sourcing strategies and qualify suppliers
- 3 to 6 months: Finalize material qualifications. Document material development results.
How Fiber Optic Sensing Can Help
Sensuron’s fiber optic sensing platforms collect spatially continuous, real time strain, temperature, deflection data and more. This can help validate models faster and much more precisely than traditional electronic based sensors like strain gauges and thermocouples. Since these legacy technologies are point sensing solutions, they can miss important events that occur between critical points. Sensuron’s technology is able to collect data about entire strain fields and temperature distributions so information about critical points and everywhere in between can be captured. Armed with this data, engineers can more confidently validate new materials for use in automotive designs.
In addition to supplying significantly more data than legacy sensor technology, the sensing fiber can be installed in considerably less time. On average, it takes the same amount of time to install 3-5 strain gauges as it does ten meters of sensing fiber. Ten meters of Sensuron’s sensing fiber is equivalent to approximately 1,000 sensing points with 6.3 mm gauge spacing. When considering a test installation, as the number of required strain gauges increases, the time saved by switching to fiber optic sensing increases exponentially.
Some fiber optic sensing platforms can monitor multiple parameters at the same time. At Sensuron, we refer to this as multi-sensing. A multi-sensing platform allows users to replace multiple disparate sensor technologies with a single sensing platform. This improves efficiency across an organization by reducing the types of data acquisition hardware needed to perform a variety of tests. For example, Sensuron’s multi-sensing interrogators (the data acquisition unit for fiber optic sensors) can simultaneously monitor strain, load, temperature, deflection, pressure and the 3D shape of the fiber. While installation practices will vary depending on what measurements need to be taken, the same hardware can be used for each measurement. Multi-sensing is beneficial when it comes to testing new materials for lightweighting automotive designs in that a component or assembly can be instrumented with a few fibers to simultaneously observe strain, load distributions, temperature, and deflection – all critical measurements for strain analysis and model validation.
While fiber optic sensing cannot address all the challenges that automakers face in lightweighting their designs, the technology can help accelerate the time to market for new materials required by lightweighting efforts. As legislation continues to push automakers to innovate, new sensing paradigms are needed. Fiber optic sensing can help automotive organizations meet these new requirements.