Browse Topic: Weather-stripping
Weather-strip sealing systems are critical to automotive closure performance, influencing water- and dust-tightness, aerodynamic noise control, and overall NVH quality. Conventional validation often relies on flat or straight JIG-based tests that inadequately represent the curved, angled, and non-uniform geometries of real closures such as doors, tailgates, hoods, roofs, and fixed or movable glass. This disparity limits the predictive accuracy of sealing performance in actual vehicles. This study proposes a vehicle-integrated validation framework that mirrors true geometric and contact conditions. The methodology combines finite element analysis (FEA) of both flat JIG and full-vehicle CAD geometries with experimental JIG tests, establishing a baseline for pressure distribution, compression load, and sealing contact behavior. A comparative analysis highlights significant deviations between flat-section predictions and vehicle-specific closure profiles. Results demonstrate that the integrated method more accurately reflects sealing efficiency, sound transmission loss, and long-term deformation, offering improved reliability for early-stage NVH optimization and product qualification. The findings recommend incorporating vehicle-profile-based validation into standard development practice for automotive weather-strips.
This study focuses on the numerical analysis of weather-strip contact sealing performance with a variable cross-sectional design, addressing both static and dynamic behaviors, including the critical issue of stick-slip phenomena. By employing finite element modeling (FEM), the research simulates contact pressures and deformations under varying compression loads, DCE (Door Closing Efforts) requirements, typical in automotive applications. The analysis evaluates how changes in the cross-sectional shape of the weather-strip affect its ability to maintain a consistent sealing performance, especially under dynamic vehicle operations. The study also delves into stick-slip behavior, a known cause of noise and vibration issues, particularly improper/ loosened door-seal contact during dynamic driving condition. This study identifies key parameters influencing stick-slip events, such as friction coefficients, material stiffness, surface interactions, sliding velocity, wet/dry condition. Numerical simulations are used to predict stick-slip tendencies, and potential improvements, such as optimizing material properties or altering geometric profiles, are proposed. The results demonstrate that optimizing the variable cross-section can significantly enhance sealing performance, leading to better noise, vibration, and harshness (NVH) characteristics. Additionally, adjustments to material properties and geometric profiles are shown to reduce stick-slip effects, contributing to quieter and more reliable weather-strip systems in automotive applications. The findings of this study offer valuable insights for the design of more effective weather-strip systems in modern vehicles
This paper deals with vehicle door 120-degree joint rust issue and water leak faced in most of SUV cars. Generally based on vehicle segment its styling curves and exterior design are defined. A Sedan or Hatchback is provided with curves to show its fluidic design but a SUV is provided with Straight lines to show its aggressive look. In existing condition door frame Joint has sharp joints where weld bead is added to prevent rust in joint area, but still improper seating of weather strip on weld bead cause water leak. Door’s A Pillar Frame and Horizontal Frame match at 120 degree joint edges are chamfered straight to match perfectly. Weld bead runs over the matching profile to join it. But weld bead project over the Frame surface and affects weather strip seating & results in poor sealing. Adhesive added for better sealing also follows the same path on bead and create a path way for water entry. Thus in long run this water stagnates and cause chronic rust issues in frame. This in turn results in high claim cost within warranty period. It is serious issue which should be addressed. This paper investigates deeply the process of eradicating the rust issue and water leak issue simultaneously. Edges of frame are provided with forming at 120 Joint matching areas. So that weld bead gets sink into shallow depth without projecting out from the surface. This flattened profile of weld bead on frame surface results in perfect sealing of weather strip. This is how sink weld prevents rust and arrest water entry.
A method including Multi-Body Dynamics (MBD) and fatigue assessment process with modal approach was developed to predict Light Commercial Van (LCV) Rear French Doors open/close durability performance during early design stage to improve test detect ability. The nonlinear properties of joints, such as those on bolted housings or spot welds sheets and hem flange areas, can substantially influence the local and global results of a dynamic simulation. The Modal approach considers joint contact, by way of Joint Interface Modes (JIMs) by using Contact Subroutine (MAMBA) to co-simulate with MBD software to improve result quality. One of the main challenges is measuring the dynamic stiffness for the weather strip. A novel test method was used to measure the weather strip dynamic stiffness by conducting an “in-situ” test. For CAE simulation results, positive feedback was received from design and test engineers.
The automotive weather strip performs functions of isolating water, dust, noise and vibration from the outside. To achieve good sealing performance, weather strip should be designed to have the high contact force and wide contact area. The compression load of weather strip is important for closing force in initial quality, but the permanent deformation is used to predict influx of wind noise over long periods of time. To check these accurately and easily, a new test method is demanded. So this paper introduces a new test method to predict the compression load and permanent deformation of 3D full vehicle by using ABAQUS. Uniaxial tension and creep tests were conducted to obtain the material data. The lab test for the permanent deformation was accelerated at high temperature during shorter time of 300 hours. Herein Proposed test method can provide accurate prediction under the different loading conditions and section shapes, and will also save time and cost.
In an attempt to predict the responses of side crash pressure sensors, the Corpuscular Particle Method (CPM) was adopted and enhanced in this research. Acceleration-based crash sensors have traditionally been used extensively in automotive industry to determine the air bag firing time in the event of a vehicle accident. The prediction of crash pulses obtained from the acceleration-based crash sensors by using computer simulations has been very challenging due to the high frequency and noisy responses obtained from the sensors, especially those installed in crash zones. As a result, the sensor algorithm developments for acceleration-based sensors are largely based on prototype testing. With the latest advancement in the crash sensor technology, side crash pressure sensors have emerged recently and are gradually replacing acceleration-based sensor for side impact applications. Unlike the acceleration-based crash sensors, the data recorded by the side crash pressure sensors exhibits lower frequency and less noisy responses which is more conductive for CAE prediction. In the attempt to predict the side crash pressure sensor responses, fourteen different benchmark tests were designed and conducted to provide data for model validations. The fourteen benchmark tests can be divided into three sets based on the structure designs. The first set of benchmark tests included a rectangular rigid container with one side being compressed while all other sides were fixed to simulate a piston compression condition. The second set of benchmark tests contained a rigid impactor or a deformable barrier hitting a rectangular steel box with and without a hole. Different speeds were chosen in the second set of benchmark tests to obtain the corresponding pressure responses. The third set of benchmark tests involved a rigid impactor or a deformable barrier hitting a real vehicle side door with different openings. In the baseline door test, the window weather strip and speaker were kept and all holes in door inner were closed to represent a production door. To ensure the robustness of CAE predictions for different door designs, the window weather strip was removed and some holes in the door inner were opened in some of the door benchmark tests. Computer models were created according to the corresponding test conditions. The CPM method originally developed in LS-DYNA to simulate the deployments of side air bags and side air curtains was adopted and improved in this research to predict the responses of the side crash pressure sensors. One of the main purposes of adopting such method in this project is trying to expand the application of the CPM method to problems that do not involve inflators. With major improvements in the CPM method through this research in the past two years, not only the responses of side crash pressure sensor can be predicted but also the computation time required to complete such simulations has been shortened. The development of the modeling methodology to predict the responses of the side crash pressure sensors will also make it possible to use computer simulations as part of side crash sensor development and results in more robust sensor firing algorithm.
Understanding the resonant behavior of vehicle closures such as doors, hoods, trunks, and rear lift gates can be critical to achieve structure-borne noise, vibration, and harshness (NVH) performance requirements, particularly below 100Hz. Nearly all closure systems have elastomer weatherstrip components that create a viscoelastic boundary condition along a continuous line around its perimeter and is capable of influencing the resonant behavior of the closure system. This paper outlines an approach to simulate the static and dynamic characteristics of a closed-cell Ethylene Propylene Diene Monomer (EPDM) foam rubber weatherstrip component that is first subjected to a large-strain quasi-static preload with a small-strain sinusoidal dynamic load superimposed. An outline of a theoretical approach using “phi-functions” as developed by K.N. Morman Jr., and J.C. Nagtegaal [1] is introduced followed by a discussion of the material characterization that was done to construct a suitable elastomer material model for finite element analysis (FEA). Next, to validate the approach, the FEA and correlation of a simple extension specimen is presented followed by the analysis and correlation of a weatherstrip component with a complex cross sectional shape. It is observed that the static and/or dynamic response of the weatherstrip material and component can be dependent on several factors such as excitation frequency, large-strain preload, vibration amplitude, component geometry, and friction. Correlation between simulation and experimental results for dynamic stiffness and loss factor are in general agreement below 100Hz.
The minimum door closing speed is an important target in vehicle door design. Engineers need a proper method to evaluate the door closing speed during the design phase. Analytical approaches are presented to solve the difficult issues in analyzing the minimum door closing speed. First, the weather strip is simplified into a discrete model with several spring elements. This method does not need to use 3-D contact analysis for the weather strip and can save computing time with acceptable accuracy. Second, the minimum closing speed is solved by using the energy equation which needs one iteration only. The method has high efficiency and can be used to evaluate the door closing speed effectively during the design phase.
The sixth-generation car delivers even more performance value than its predecessor, and adds greater comfort and convenience into the mix. Better performance value-than its predecessor and competitors-helped the re-engineered C6 Chevrolet Corvette (see the October 2004 AEI for a full review) take home AEI's Best Engineered Vehicle honors for 2005. Along with a more powerful engine and better ride and handling than the C5 it replaces, engineers were able to address consumer demands for more refinement and include first-time features such as OnStar and DVD-based navigation options. “Our goal was a performance car at home in virtually any environment,” said Dave Hill, Chief Engineer of the Corvette and Vehicle Line Executive for General Motors Performance Cars including the Corvette's platform-mate, the Cadillac XLR. “That means more than just raw performance. It calls for improved ride comfort, a precisely built and technically sophisticated interior, and a sleek new body that is fresh and contemporary, while still instantly recognized as the new Corvette.”
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