Strength Prediction of Bumper by Correlating FEA with Test 2011-01-2155
To develop new markets and to respond to voice of the customers, new specifications for special components are developed from time to time. To meet new specification, the strength and durability of components need to be reevaluated in a relatively short time. The cost associated with design lead-time, re-tooling, physical prototypes, test validation and fabrication of late changes are big challenges. The industrial leading golf and utility vehicles from E-Z-GO are equipped with impact-protecting components, such as front bumper, rear bumper, floorboard, front cowl, rear body and operator station. To respond to the voice of the customer, new requirements for corner impact protection were added to existing vehicle specification for 360 degree impact protection. Virtual prototyping was introduced to accelerate redesign process and to save valuable time and money.
The crash mechanism itself is complex and difficult to analyze sometimes. The life of the component including fracture and fracture propagation is relatively difficult to predict, if the required impact is less than 100 impacts. The material properties of polymer and its fiber orientation present additional complicating factors. The simplifications and assumptions in FEA modeling require verifications. This article introduces a relative simple and practical virtual prototyping method for such redesigned components.
Initially, the rear corner impact was designed to be taken by other vehicle components besides the bumper. Therefore, the original rear bumper was unable to withstand corner impact. A simple reinforced rear bumper as a starting stage was built and tested. Although it did not pass the new requirement, it was used for FEA correlation and served as a reference for redesign. A FEA model for this reinforced rear bumper was developed and correlated with test results. The redesigned model was developed based on correlated parameters and analyzed in order to optimize design and predict the strength. By means of correlating a simplified FEA model with test results, this application was used to predict the strength of future new products and to improve the design. Based on the analysis, the design was optimized, a group of physical prototypes was built and these samples have passed all required tests. Field usage by our customers has proven the success of this design and analysis process.