In the era of fierce competition, launching a defect free product on time would be the key to success. In modern automobile, the transmission system is designed with utmost care in order to transfer the maximum power from engine to driveline smoothly and efficiently. Optimized design of all the transmission components is necessary in order to meet the power requirement with the least possible weight. Transmission bush failure was observed in one of the transmissions during complete system level testing. Bushes are generally press fitted on the main shaft and counter shaft on which the needle roller bearing is mounted. In some cases, the free axial movement of the gear is restricted by the hub or shaft itself. But in other cases, due to assembly constraints, the bush itself is flanged to restrict the axial free play of the gear. When the respective gear is not in engaged condition, the bush does not get any axial thrust. Once the gear is engaged, due to the axial thrust caused by the helical gear, the bush experiences…

Automotive Wheel Hub is a safety critical component. Integrated Wheel hub design is improved from 1st generation to 3rd generation to meet the durability targets with less weight. Lateral loading is critical parameter for designing wheel hub. Cornering test is performed at vehicle level to evaluate wheel hub. Cornering test has combination of three types of tracks. In Wheel hub design, flange radius and flange width are two important design parameters to meet the durability life for cornering loads. We have considered the combination of different flange radius and flange width to understand the effect of these two parameters on wheel hub fatigue life. These three-wheel hubs are tested till failure and life scatter is plotted. Strain data is acquired at flange radius on wheel hub for all cornering test tracks. Using Wheel Force Transducers (WFT), Forces and moments are acquired at wheel center for all cornering test tracks. Duty cycle is derived from measured loads. FE model of Wheel end simulation contains Wheel hub, Wheel rim, Knuckle, drive shaft and wheel nut. FE Analysis…

An examination of field-fractured windshields was conducted for the purpose of determining their principle fracture mechanisms experienced in-use. Parts for the study were gathered both in the United States (state of NY) and in Europe (France) to explore whether the primary causes of failure were similar or different for the different regions. In total, over two hundred individual field-fractures were obtained and examined for the study. Detailed fracture analysis of the parts was performed, and several different fracture mechanisms were identified and quantified. It was found that the two most dominant failure modes were common for both geographic regions. The most frequent cause (~70%) of windshield fracture was due to sharp particle impact of the exterior ply, while Hertzian cone cracking of the outer ply was the second leading cause (~20%). These and other observed failure modes are detailed below. Given that sharp impact fracture was the dominant failure mode observed, a new high-speed, sharp impact test method was developed and deployed to evaluate numerous laminate constructions for their resistance to this type of event.…

According to increasing the demands of light-weight design in the automotive industry, the usage of thinner and lighter materials such as aluminum alloy has led to significant weight reduction. The joining of these materials has required new technologies in joining/fastening rather than welding. Flow drill screw (FDS) is one of the latest technologies to fasten sheet metal panels. This paper discusses the results of an evaluation of the fatigue characteristics of FDS joints based on experimental data and observations from the literature. It was observed that the important geometric parameters of FDS joints are the gap between panels and the extruded (or bulged) zone during screwing. Major failure modes were observed as panel failure which cracks grow from the inner surface of the panel around the bulged zone. In this paper, the fatigue evaluation procedure for FDS joints using the mesh-insensitive equilibrium-based structural stress (ESS) method was proposed. The ESS-based simplified modeling procedure was used for the fatigue evaluation procedure development for FDS joints. The effectiveness and applicability of the ESS-based simplified procedure for modeling…

Today engine downsizing, weight reduction, boosting, etc. are widely used in modern combustion engine designs in order to increase power output, improve fuel economy, and reduce emission. However utilizing of these advanced technologies is making the engine less rigidity and resulting in potential fretting damages on any contact surfaces of engine components due to higher cyclic relative motions. The leakage failure of the cylinder-head sealing system induced by fretting damage on engine head and block deck surfaces is the one of major failure modes in the modern combustion engine. In this paper, the characteristics and failure modes of the MLS head gasket sealing system is introduced first. The fretting mechanism between MLS head gasket and engine head and block is then investigated and a fretting damage parameter and a damage criterion as well are defined and established to evaluate the crack nucleation or wear initiation. Also it is important to identify two types of loads during engine operation in the fretting damage calculation. The developed methodology is successfully verified through a good correlation between CAE…

Abstract This paper studied the process development of dissimilar clinch joints in cross-tension specimens of aluminum alloy 5052-H32 (AA5052-H32)/thermoplastic carbon fiber reinforced plastic (TP-CFRP) sheets. The AA5052-H32 and TP-CFRP sheets with a thickness of 1.6 mm were used. The critical processing parameters for AA5052/TP-CFRP clinch joints, such as the compressive load, pre-heating type, pre-heating temperature, and die depth, were considered. The failure loads, failure modes, and metallographic micrographs of AA5052/TP-CFRP clinch joints were analyzed to determine an available processing parameter set for fatigue tests. Finally, fatigue performance and failure modes of AA5052/TP-CFRP clinch joints were obtained.

Noorsumar; Gulshan, Rogovchenko; Svitlana, Vysochinskiy; Dmitry, Robbersmyr; Kjell.G, University of Agder, Norway Keywords: UHSS (Ultra-high strength steel); LS Dyna; Finite Element (FE); MIG welding; HAZ (Heat Affected Zone); Crashworthiness; Repaired Car The word ‘crashworthiness’, [1] first used in the aerospace industry around the early 1950’s provided a measure of the ability of the structure to protect its occupants in survivable crashes. In the automotive industry the term refers to the measure of vehicle’s structural abilities to plastically deform and absorb sudden impact loads while maintaining enough survival space for the occupants. The goal of crashworthiness: Vehicle structures should be stiff in bending and torsion for proper ride and handling and should plastically deform in the event of a crash and absorb energy to prevent intrusions in the driver compartment. The structural integrity of cars comes at the cost of weight and fuel economy at times and engineers struggle to find the perfect balance between weight and crash performance. [2] The emergence of active and passive safety technologies has helped to resolve this issue and use…

Numerical modeling of lithium-ion battery cells and modules under abuse loading conditions Feng Zhu, Xianping Du, Jianyin Lei, Lorenzo Audisio, David Sypeck Embry-Riddle Aeronautical University 1 Aerospace Blvd. Daytona Beach, FL 32114 Abstract Lithium-ion (or Li-ion) battery systems have been increasingly used as the main power source in new generation hybrid and electric vehicles. Their mechanical integrity under abuse loading conditions is very important for vehicle safety design. In this research, a computational study has been performed to simulate previously conducted mechanical tests on vehicle battery cells and modules. The tests were conducted on a commercial Li-ion battery cell and module at low speed using a high capacity material testing system. According to the loading and boundary conditions in the tests, a finite element (FE) model based on an explicit FEA solver LS-DYNA, was developed. The model predictions demonstrated reasonable agreement in terms of failures modes and force-displace response at both cell and module level. Using the validated numerical model, a parametric study was performed to investigate the contribution of each component in the battery…

A challenge in structural design is the inability to quickly assess how a change in use can affect the structural performance of the system. This is particularly important in the bus industry with multiple variations of one base product type for many customers. Thus for a single design there can be frequent changes to mission profiles or customer constraints, which must be considered within short time periods before production commences for a particular customer. This can often limit full understanding of the structural performance, key structural features or critical failure modes, ultimately limiting the potential for producing buses with minimum structural mass. The proposed method in this paper aims to develop a design tool capable of rapidly informing structural design engineers with respect to the structural limitations of various vehicle components using performance envelopes. Vehicle performance envelopes define the combination of global vehicle accelerations (lateral, vertical and longitudinal) that cause structural failure of any feature or component included in the envelope. Additionally, envelopes will enable definition of the critical (non-redundant) and redundant structural failure modes…

Composite materials are a natural choice for engineering applications where mechanical performance and lightweight are required, as in state-of-the-art components in the automotive field. Nevertheless, close attention should be paid to defects present in this kind of structure. Several innovative ways to investigate the failure mode of structures in composite material has been developed in time. This paper presents the experimental characterization of piezoelectric transducers as a Structural Health Monitoring System: a continuous acquisition system of data in order to real time detect the presence of faults inside automotive components under analysis. Several tests have been executed over a PI-DuraAct piezoceramic patch coupled to a host structure, characterizing the acquisition and transmission of a signal. Contribution about bonding quality, shape wave distortion of imposed signal and best frequency for transmission have been evaluated. Furthermore, the damage was created in a controlled drop-dart tower and its intensity analyzed with a C-scan non-destructive test. An algorithm has been then implemented in MATLAB to obtain detection of defects and their intensity, by processing the data acquired. Two case…