Kenneth N. Morman

Nonlinear analysis of automotive door weatherstrip seals

Abstract Automotive door system weatherstrip seals play a major role in determining door closing effort, isolating the passenger compartment from water and reducing the wind noise inside the vehicle. Using nonlinear finite element analysis, a seal cross section can be analyzed for compression load deflection (CLD) behavior, contact pressure distribution and aspiration due to a pressure differential across the seal. The seal CLD response, the deformed shape during compression, the contact pressure distribution and the aspiration pressure difference are all important seal performance factors that are considered in door weathership seal design. The analyses described herein and the associated design evaluations can be performed before any prototype hardware is developed if sufficient geometry and material property information is available.

On the effect of an interfacial layer on the fracture behavior of interface and subinterface cracks in single-lap shear joints

Linear elastic fracture mechanics (LEFM), combined with a 2-D finite element analysis based on a p-version finite element code, PROBE, was applied to study interface and subinterface cracks in single-lap shear joints. The effects of the thickness and properties of interfacial layer on the fracture property of adhesive joints were examined. The results show that, in general, the stress intensity factors (SIFs) are strongly influenced by the ratio of the Youngs modulus of the interfacial layer to that of the adhesive, but they are less sensitive to the thickness of the interfacial layer (within 0.01-0.03 mm). In addition, the longer the crack length, the larger the magnitude of the SIF, which shows an increasing crack driving force with crack length. Aside from the differences in the magnitude of SIFs and those in the variations of K2 and KII, where K2 and KII are the Mode II components of the interfacial and subinterfacial SIFs, respectively, the general trend of the variations of SIFs with respect to the...

Supervisory vehicle impact anticipation and control of safety systems

Occupant safety systems are incorporated in vehicles to meet the requirements of occupant protection. For optimum performance safety devices require tailored activation. This paper presents a supervisory control approach using predictive collision sensor information to augment the performance of safety systems. The supervisory approach determines the potential for a collision to occur, and assists in deployment decision-making. Decision-making is based on the obstacle range, and closing velocity information obtained from the anticipatory sensor, and a reference signal indicative of the host-vehicle deceleration. The multi-input supervisory control system consists of a fuzzy rule-based system, which determines the potential for a collision to occur, and deployment command generation for activation of respective safety devices.

A viscoelastic analogy for solving 2-D electromagnetic problems

Abstract Solving a viscoelastic material boundary value problem provides the voltage, electric field and displacement current results to a certain class of electromagnetic problems. By means of the electromagnetic-viscoelastic analogy described herein, a solid mechanics finite element program can analyze a two-dimensional harmonic oscillation (constant frequency) electromagnetic problem for “lossy” dielectric materials. For this special class of electromagnetic field problems, the Maxwell equations reduce to a two-dimensional Laplace equation with complex coefficients. This form identically matches the viscoelasticity field equations. This paper develops the electromagnetic-viscoelastic analogy from the basic governing field equations. The analogy is implemented in ABAQUS, a general solid mechanics finite element program. Simple one- and two-dimensional examples prove the accuracy and usefulness of the analogy.