Siemens PLM Software LMS Engineering services Body-flexibility methodology for driving dynamics Gaining insight into the relationship between body stiffness and vehicle handling Benefits • Provide insight into the relationship between body stiffness characteristics and vehicle performance • Visualize body deformation during handling maneuvers • Improve the body targetsetting process • Balance the conflict between vehicle handling and NVH performance • Improve driving dynamics by targeted structural body design modifications • Relate the subjective driver feeling to objective measures Summary LMS™ Engineering services has developed a method that provides more insight into the relationship between body stiffness and driving dynamics. It enables you to better balance the conflict between handling and noise, vibrations and harshness (NVH) performance earlier in the development process. Although test and simulation technologies for suspension development for driving dynamics are well established, body design and body target setting for vehicle handling performance are more complex. Reinforcements for better driving dynamics are often applied based on experience or by trial-and-error. This can cause expensive body design changes late in the vehicle development process, which can result in production delays and increase costs. LMS Engineering experts have developed a unique test-based methodology that provides insight into the relationship between body stiffness characteristics and vehicle performance. Car body flexibility influences the handling performance, including the subjective driving experience. Traditional approaches, such as body static stiffness tests, can objectively quantify the effect of reinforcements into a single static stiffness value. But when evaluating on the track in operational conditions, real objective global vehicle performance quantities, such as yaw-rate, lateral acceleration or roll angle, are typically difficult to directly relate to body stiffness changes. As these performance indicators result from the combined effect of all forces between suspension and body, individual contributing body forces can change in relevant amounts, while the combined effect can still be small. Insight into these force mechanisms is crucial for studying different body www.siemens.com/plm/lms LMS LMS Engineering services Body-flexibility methodology for driving dynamics variants. Therefore, carmakers are looking for technologies that provide a better understanding of the relation between body flexibility and handling performance. LMS Engineering has developed a unique test-based technology that enables you to visualize body deformation during handling maneuvers, and decompose it into contributions of global body deformations, such as body torsion and bending, and local body deformations. This methodology can also be used to improve the body stiffness target-setting process, allowing engineers to better balance the conflict between handling and NVH performance while designing a next-generation lightweight platform. A typical body flexibility project is comprised of the following phases: Identification of contact forces In the first phase, the individual timedomain forces in the connection points between suspension and body are identified. This is done using the matrixinversion method based on strain-gauge measurements. Body strain measurements. Body deformation during maneuver. Investigation of body deformation In the second step, the identified timedomain loads are combined with a modal model of the trimmed body to visualize body deformation during handling maneuvers. This deformation can be decomposed into contributions of global body deformations, such as body torsion and bending, and local body deformations. Targeted improvement of the body design The results identify weak body areas, and show where structural modifications can be more effective. They allow setting body stiffness targets and applying efficient modifications while considering the call for lightweight vehicles. Contact Siemens PLM Software Americas +1 248 952 5664 Europe +32 16 384 200 Asia-Pacific +852 2230 3308 www.siemens.com/plm Instrumented vehicle. © 2015 Siemens Product Lifecycle Management Software Inc. Siemens and the Siemens logo are registered trademarks of Siemens AG. LMS, LMS Imagine.Lab, LMS Imagine.Lab Amesim, LMS Virtual.Lab, LMS Samtech, LMS Samtech Caesam, LMS Samtech Samcef, LMS Test.Lab, LMS Soundbrush, LMS Smart, and LMS SCADAS are trademarks or registered trademarks of Siemens Industry Software NV or any of its affiliates. All other trademarks, registered trademarks or service marks belong to their respective holders. 44870-Y4 2/15 C