Impact detection for smart automotive damage mitigation systems

Abstract

Occupant safety and severity of vehicle damage are important factors in automotive vehicle design. Smart automobiles of the future could potentially use distributed smart material sensors and actuators in order to identify impact and take appropriate evasive or mitigative actions. This provides the motivation for this study.The first part of this study is focused on detecting the location and magnitude of impact, particularly for the case where the automotive structure is subjected to minimal damage. This is accomplished by developing a generalized algorithm using the Reissner-Mindlin plate theory, the Rayleigh-Ritz energy approach, and the Lagrangian-Hamilton principle. The level of performance of this methodology is demonstrated for impacts on a simply supported rectangular plate. Different case studies for static as well as impact loading with point as well as area contacts are presented. An algorithm using deconvolution for identifying impact location and magnitude has been developed and implemented. Additionally, the influence of damage on the structural vibratory content is studied via a frequency analysis. The modal analysis for undamaged and damaged plates, with nine different damage locations and six different damage sizes are performed. Changes in frequency and mode shapes are observed in regard to the severity of the damage.

Impact detection for smart automotive damage mitigation systems

“…With the above general equation obtained, the level of performance of the methodology is demonstrated for a case of a simply supported plate subjected to a point load contact. The forward model verification (identifying displacements and strains for a given force) for area contact [2] and a limiting case of static load has been reported by the authors in a previous publication [9]. Forward model results for the case of a point contact impact load are presented in section 2.2.…”

“…Each sine term in the above equation satisfies conditions at the edges which require that: w = ∂ 2 w/∂ 2 x = 0 at x = 0, a; and w = ∂ 2 w/∂ 2 y = 0 at y = 0, b. With these displacements, the stress [8], strain, and moments are computed [2] to obtain the variation in the work done by external forces, strain energy, and kinetic energy of the plate [5]. The Hamilton principle is…”

“…This section considers a case study on 450 mm × 350 mm × 2 mm aluminum plate simply supported on all sides. Here, once equation ( 4) is solved for γ mn (t), the displacement in the z direction w(x, y, t) is found using equation (2). A relatively large number of modes are required to achieve convergence, especially for different boundary conditions on the four sides of the plate [2].…”

“…Here, once equation ( 4) is solved for γ mn (t), the displacement in the z direction w(x, y, t) is found using equation (2). A relatively large number of modes are required to achieve convergence, especially for different boundary conditions on the four sides of the plate [2]. For the case of the simply supported plate considered subsequently, ten modes are found to be sufficient for convergence [5].…”

“…Figure 1 shows a schematic diagram of smart material sensor implementation on an automotive panel that can detect real time impact and provide appropriate information to the damage identification processor in an automobile. The system shown in the schematic diagram shown on the left side of figure 1 can locate and reconstruct the impact force [2]. Also, the system shown in the schematic diagram on the right side can assess the damage severity for larger impacts [3].…”