Browse Topic: Body structures
The pre-validation process for door trim noise has gained increasing importance as noise standards have become more stringent with the transition to electric vehicles. Currently, the validation process employs squeak and rattle director simulations to evaluate noise based on relative displacement values. However, this approach is time-intensive. To address this limitation, we have improved process efficiency by developing a database of relative displacement values derived from the cross-sectional and structural characteristics of matching parts. This advancement enables noise pre-validation using only cross-sectional and structural information.
The proliferation of the electric vehicle (EVs) in the US market led to an increase in the average vehicle weight due to the assembly of the larger high-voltage (HV) batteries. To comply with this weight increase and to meet stringent US regulations and Consumer Ratings requirements, Vehicle front-end rigidity (stiffness) has increased substantially. This increased stiffness in the larger vehicles (Large EV pickups/SUVs) may have a significant impact during collision with smaller vehicles. To address this issue, it is necessary to consider adopting a vehicle compatibility test like Euro NCAP MPDB (European New Car Assessment Program Moving Progressive Deformable Barrier) for the North American market as well. This study examines the influence of mass across vehicle classes and compares the structural variations for each impact class. The Euro NCAP MPDB (European New Car Assessment Program Moving Progressive Deformable Barrier) protocol referenced for this analysis. Our evaluation
Plasticized polyvinyl chloride (PVC) has many applications in automotive industry including electrical harnesses, door handles, seat and head rest covers, and instrument panel (IP) and other interior trim. In IP applications, the PVC skin plays a critical role in passenger airbag deployment (PAB) by tearing along the scored edge of the PAB door and allowing the door to open and the airbag to inflate to protect the occupant. As part of the IP, the PVC skin may be exposed to elevated temperatures and ultraviolet (UV) radiation during the years of the vehicle life cycle which can affect the PVC material properties over time and potentially influence the kinematics of the airbag deployment. Chemical and thermal aging of plasticized PVC materials have been studied in the past, yet no information is found on how the aging affects mechanical properties at high rates of loading typical for airbag deployment events. This paper compares mechanical properties of the virgin PVC-based IP skin
Physical testing is required to assess multiple vehicles in different conditions, specially to validate those related to regulations. The acoustic evaluations have difficulties and limitations in physical test; cost and time represent important considerations every time. Additionally, the physical validation happens once a prototype has been built, this takes place in a later phase of the development. Sound pressure is measured to validate different requirements in a vehicle, horn sound is one of these and it is related to a regulation of united nations (ECE28). Currently the validation happens in physical test only and the results vary depending on the location of the horn inside the front end of every vehicle. [7] In this article, the work for approaching a virtual validation method through CAE is presented with the intention to get efficiency earlier in product development process.
The current Range Rover is the fifth generation of this luxury SUV. With a drag coefficient of 0.30 at launch, it was the most aerodynamically efficient luxury SUV in the world. This aerodynamic efficiency was achieved by applying the latest science. Rear wake control was realised with a large roof spoiler, rear pillar and bodyside shaping, along with an under-floor designed to reduce losses over a wide range of vehicle configurations. This enabled manipulation of the wake structure to reduce drag spread, optimising emissions measured under the WLTP regulations. Along with its low drag coefficient, in an industry first, it was developed explicitly to achieve reduced rear surface contamination with reductions achieved of 70% on the rear screen and 60% over the tailgate when compared against the outgoing product. This supports both perceptions of luxury along with sensor system performance, demonstrating that vehicles can be developed concurrently for low drag and reduced rear soiling
Door sunshade in a vehicle has proven to be very comfortable and luxurious feature to the customers. Luxury vehicles provide power sunshade which is electrically operated with the activation of a switch, whereas cost conscious vehicles provide manual sunshade which requires manual coiling and uncoiling. This study is to develop a door panel structure that can accommodate both the manual sunshade and power sunshade, thereby serving both cost conscious as well as luxury seeking customers. Manual sunshade consists only of cassette, pull bar, spindle mechanism and hooks whereas the power sunshade consists of cassette, pull bar, spindle mechanism, flap mechanism, bowden cable mechanism, actuator and motor. Due to this difference in package, it becomes difficult to accommodate both variants of sunshade into the same body system. However, this study helps in developing a common body structure by ways of effective packaging, modifying the cable and actuator mechanism and critical packaging of
This paper presents a new regression model-based method for accurate predictions of stiffness of different glass laminate constructions with a point-load bending test setup. Numerical FEA models have been developed and validated with experimental data, then used to provide training data required for the statistical model. The multi-variable regression method considered six input variables of total glass thickness, thickness ratio of glass plies as well as high-order terms. Highly asymmetrical, hybrid laminates combining a relatively thick soda-lime glass (SLG) ply joined with a relatively thin Corning® Gorilla® Glass (GG) ply were analyzed and compared to standard symmetrical SLG-SLG constructions or a monolithic SLG with the same total glass thickness. Both stiffness of the asymmetrical laminates and the improvement percentage over the standard symmetrical design can be predicted through the model with high precision.
Customers are expecting higher level of refinement in electric vehicle. Since the background noise is less in electric vehicle in comparison with ICE, it is challenging for NVH engineers to address even minor noise concerns without cost and mass addition. Higher boom noise is perceived in the test vehicle when driven on the coarse road at a speed of 50 kmph. The test vehicle is rear wheel driven vehicle powered by electric motor. Multi reference Transfer Path Analysis (TPA) is conducted on the vehicle to identify the path through which maximum forces are entering the body. Based on the findings from TPA, solutions like reduction in the dynamic stiffness of the suspension bushes are optimized which resulted in reduction of noise. To reduce the noise further, Operational Deflection Shape (ODS) analysis is conducted on the entire vehicle to identify the deflection shapes of all the suspension components and all the body panels like floor, roof, tailgate, dash panel, quarter panel and
During the early phase of vehicle development, one of the key design attributes to consider is the trunk. Trunk is the pillar that is responsible for user’s accommodate their baggage and make into customer needs in engineer metrics. Therefore, it is one of the key requirements to be considered during the vehicle design. Certain internal vehicle trunk characteristics such as the trunk height and length are engineer metrics that influence the occupants’ perception for trunk. One specific characteristic influencing satisfaction is the rear opening width lower for notch back segment, which is the subject of this paper. The objective of this project is to analyze the relationship between the rear opening width lower with the occupant’s satisfaction under real world driving conditions, based on research, statistical data analysis and dynamic clinics.
Modal performance of a vehicle body often influences tactile vibrations felt by passengers as well as their acoustic comfort inside the cabin at low frequencies. This paper focuses on a premium hatchback’s development program where a design-intent initial batch of proto-cars were found to meet their targeted NVH performance. However, tactile vibrations in pre-production pilot batch vehicles were found to be of higher intensity. As a resolution, a method of cascading full vehicle level performance to its Body-In-White (BIW) component level was used to understand dynamic behavior of the vehicle and subsequently, to improve structural weakness of the body to achieve the targeted NVH performance. The cascaded modal performance indicated that global bending stiffness of the pre-production bodies was on the lower side w.r.t. that of the design intent body. To identify the root cause, design sensitivity of number and footprint of weld spots, roof bows’ and headers’ attachment stiffness to BIW
The stiffness and positioning of engine mounts are crucial in determining the powertrain rigid body modes and kinetic energy distribution. Therefore, optimizing these mounts is essential in the automotive industry to separate the torque roll axis (TRA) and minimize vibration. This study aims to enhance mount locations by isolating the engine rigid body modes and predicting the inter-component force (ICF) and transfer function of the vehicle. The individual ICFs for engine mountings are calculated by applying a unit force at the bearing location. Critical frequencies are identified where the amplification exceeds the unit force at the mounting interface between the engine and the frame. The transfer function approach is utilized to assess the vibration at the handlebar. Both ICF and transfer functions analyze the source and path characteristics linked to critical response frequencies. This understanding aids in enhancing mounting positions to minimize vibration levels, thereby enhancing
In recent years, engineers at ETH Zurich have developed the technology to produce liquid fuels from sunlight and air. In 2019, they demonstrated the entire thermochemical process chain under real conditions for the first time, in the middle of Zurich, on the roof of ETH Machine Laboratory. These synthetic solar fuels are carbon neutral because they release only as much CO2 during their combustion as was drawn from the air for their production. Two ETH spin-offs, Climeworks and Synhelion, are further developing and commercializing the technologies.
In nature, many organisms like octopuses with their flexible tentacles or elephants with their trunks, exhibit remarkable dexterity. Inspired by these natural structures, researchers aim to develop highly flexible continuum robots that offer robustness and safety. Ideally, a continuum robot is characterized by many degrees of freedom (DOFs) and the number of joints, more than needed for most tasks. These characteristics allow them to adjust and modify their shape dynamically, enabling them to avoid obstacles and unexpected situations. However, their complex movements make it difficult to characterize their shape and motion.
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