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With the continuing challenges of future fuel economy targets carbon fiber composite materials are one facet of a lightweighting strategy to enable reduced fuel consumption. In general, use of lightweight materials such as carbon fiber composites in vehicle design generates vehicle NVH performance degradation. To address this potential issue at the design phase, there is a need to develop correlated CAE models for carbon fiber vehicle parts to evaluate the NVH impact of carbon fiber composite material use in vehicle design. To develop correlated CAE models for lightweight vehicle design with the use of carbon fiber composite vehicle body parts, an experimental study was conducted to determine the material and NVH characteristics of the carbon fiber composite materials. In this paper, the damping properties and NVH modal analysis results for structural carbon fiber thermoset composite panels and body parts (B-pillar upper insert and B-pillar lower insert) is presented.

Lightweighting of vehicle panels enclosing vehicle cabin causes NVH degradation since engine, road, and wind noise acoustic sources propagate to the vehicle interior through these panels. In order to reduce this NVH degradation, there is a need to develop new NVH sound package materials and designs for use in lightweight vehicle design. Statistical Energy Analysis (SEA) model can be an effective CAE design tool to develop NVH sound packages for use in lightweight vehicle design. Using SEA can help engineers recover the NVH deficiency created due to sheet metal lightweighting actions. Full vehicle SEA model was developed to evaluate the high frequency NVH performance of “Vehicle A” in the frequency range from 200 Hz to 10 kHz. This correlated SEA model was used for the vehicle sound package optimization studies. Full vehicle level NVH laboratory tests for engine and tire patch noise reduction were also conducted to demonstrate the performance of sound package designs on “Vehicle A”.

The desire for greater fuel efficiency and reduced emissions have accelerated a shift from traditional materials to design solutions that more closely match materials and their properties with key applications. The Multi-Material Lightweight Vehicle (MMLV) Project presents cutting edge engineering that meets future challenges in a concept vehicle with weight and life-cycle assessment savings. These results significantly contribute to achieving fuel reduction and to meeting future Corporate Average Fuel Economy (CAFÉ) regulations without compromising vehicle performance or occupant safety.

The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-I vehicle design, comprised of commercially available materials and production processes, achieved a 364kg (23.5%) full vehicle mass reduction, enabling the application of a 1.0-liter three-cylinder engine resulting in a significant environmental benefit and fuel reduction. The Regulation requirements such as the 2020 CAFE (Corporate Average Fuel Economy) standard, growing public demand, and increased fuel prices are pushing auto manufacturers worldwide to increase fuel economy through incorporation of lightweight materials in newly-designed vehicle structures.

The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-I vehicle design, comprised of commercially available materials and production processes, achieved a 364kg (23.5%) full vehicle mass reduction, enabling the application of a 1.0-liter three-cylinder engine resulting in a significant environmental benefits and fuel consumption reduction. As part of this project, several automotive chassis components were selected for development and evaluation on the MMLV C/D segment passenger sedan.

The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance, occupant safety and utility of the baseline production vehicle. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The MMLV vehicle design, comprised of commercially available materials and production processes, achieved a 364kg (23.5%) full vehicle mass reduction, enabling the application of a 1.0-liter three-cylinder engine, resulting in a significant environmental benefit and fuel reduction. This paper includes details associated with the MMLV project approach, mass reduction and environmental impact.

Vehicle interior acoustic performance is an important part of customer satisfaction. Radiating panels enclosing the vehicle cabin are very important for vehicle interior quietness. One of the most critical vehicle panels for the engine noise propagation to the vehicle interior is the dash panel. Most of the engine noise propagates through the dash panel to the vehicle interior. The dash material density, thickness and its damping properties significantly influence the dash panel sound transmission performance. In this study, the dash design of “Vehicle A” has been evaluated using the Statistical Energy Analysis (SEA) modeling and NVH testing tools. SEA and physical testing of 2′×2′ square sample panels were conducted on different dash materials and lamination materials. Dash component level and vehicle level SEA to TEST correlation results are reported to highlight the NVH performance of the dash design as well as the SEA prediction capability and its applicability in vehicle design.

Finite element analysis (FEA) predictions of magnesium beams are compared to load versus displacement test measurements. The beams are made from AM60B die castings, AM30 extrusions and AZ31 sheet. The sheet and die cast beams are built up from two top hat sections joined with toughened epoxy adhesive and structural rivets. LS-DYNA material model MAT_124 predicts the magnesium behavior over a range of strain rates and accommodates different responses in tension and compression. Material test results and FEA experience set the strain to failure limits in the FEA predictions. The boundary conditions in the FEA models closely mimic the loading and constraint conditions in the component testing. Results from quasi-static four-point bend, quasi-static axial compression and high-speed axial compression tests of magnesium beams show the beam's behavior over a range of loadings and test rates. The magnesium beams exhibit significant material cracking and splitting in all the tests.

The engine subframe (cradle) is an important contributor to crash energy management in frontal impact for automotive vehicles. Subframe design can enhance vehicle crash performance through energy management. In addition to energy management targets, the subframe must meet stiffness, durability and other vehicle engineering requirements. Various subframe concepts are reviewed. Their design intents and vehicle performance are discussed. A development process of an aluminum subframe is then presented which details the subframe design as an energy absorbing component for frontal impacts. The architecture of the subframe is developed based on overall functionality requirements and package constraints. The geometry of the subframe is first designed to accommodate engine mounts and suspension support locations. The subframe member's shape, orientation, and location are then refined to accommodate the subframe-to-body connection requirements.

The crush resistance of roof structures is critical to minimizing injuries and enhancing occupant survival during rollover crashes. Federal Motor Vehicle Safety Standard FMVSS 216 requires the roof structure to resist a load equal to one and one half (1&1/2) the unloaded weight of the vehicle during the first 127 millimeters (five inches) of deformation. This paper discusses the analytical methodologies applied and challenges encountered developing a hybrid Aluminum-Random Chop Material (RCM) roof structure. The roof structure materials are extruded 6260T6 aluminum and RCM. This hybrid roof structure has to satisfy not only the FMVSS 216 roof crush resistance, but also packaging, torsional stiffness and head impact requirements. Due to packaging constraints, the structure has to be developed without the roof bow at the B-pillar level.

At low frequencies, the finite element method reliably predicts the dynamic response of structures. At high frequencies where modal density is high, statistical energy analysis (SEA) is a useful tool to determine the global dynamic behavior of the structures. SEA gives only the space frequency band averaged energy for each subsystem. In the mid-frequency range where both short and long waves are present, neither low nor high frequency approximation to the dynamic response is valid. In this frequency range, there is a need to utilize another technique to capture the dynamic response of the structure. In this study, the energy finite element analysis (EFEA) method is evaluated as a possible technique to close the mid-frequency analysis gap related to NVH analyses. EFEA gives spatial variations of energy density and power in each subsystem, and models localized damping treatment and localized power input.