A methodology to study friction-induced squeal in a com-plete automotive disc brake assembly is presented. The analysis process uses a nonlinear static simulation se-quence followed by a complex eigenvalue extraction to determine the dynamic instabilities that are manifested as unwanted noise. The effects of assembly loads; nonuni-form contact pressure between the brake linings and disc; velocity-, temperature-, and pressure-dependent friction coefficients; friction-induced damping; and lining wear can be included. The methodology is demonstrated with a representative disc brake assembly.
Spot-welded, thin-walled curved beams, which constitute the main structural members in many automobile and other ground vehicle body structures, play a significant role in absorbing energy during a collision. Due to their extensive use, it is important to study the collapse charac-teristics of these curved members (Ref. 1). Abaqus/Explicit can be used effectively to simulate the quasi-static collapse of spot-welded structural members accu-rately.
A wide range of loading conditions must be considered in the design of a tire. Computational simulations of a quasi-static, steady-state dynamic and nonlinear transient dy-namic nature must be completed. In addition, the com-plexity and size of typical tire models highlight the need for efficient solution techniques.
Spudcans are conical footings used as foundations for offshore platforms. Installation in soft marine soil forces them deeply into the seabed, inducing gross motion and severe plastic deformation in the soil. A pure Lagrangian-based finite element approach for modeling spudcan installation and extraction can be very difficult. Because the mesh moves with the material, ele-ment distortion typically accompanies severe deformation and convergence difficulties follow.
On August 1, 2007, the I-35W highway bridge over the Mississippi river in Minneapolis, MN collapsed. The sub-sequent National Transportation Safety Board (NTSB) investigation identified the U10W truss node as a likely initiation site for the failure. (Bridge main truss nodes were numbered from the south starting at 0. U indicates a node along the upper chord, and L indicates a node along the lower chord. E and W indicate a node on the east or west truss) [1, 2, 3].
Assessing the strength of soil slopes and investigating the means for increasing their safety against failure are cru-cial in construction projects involving large soil masses. Slope stability analyses have traditionally been performed using a limit state approach. However, any presence of reinforcement or local heterogeneity necessitates the use of numerical techniques such as finite element analysis. Abaqus/Standard can be used for modeling reinforced soils and can thus help geotechnical engineers in deter-mining optimal reinforcement sizes and placement con-figurations.
Pullout resistance of driven foundation piles often in-creases with time in a process known as pile “setup.” The consolidation of the surrounding soil after the pile is driven plays a dominant role in the setup process. Finite element modeling of pile setup can help in obtaining reli-able estimates of the increase in pile resistance, which would allow for reductions in pile lengths, pile sections, or sizes of the pile driving equipment.
Finite element modeling of prestressed concrete contain-ment vessels (PCCVs, Ref. 1) for nuclear power plants poses special challenges. PCCVs, which are heavily rein-forced structures, are designed to deform beyond the cracking limits of the concrete. Abaqus has been used extensively for analyzing such structures in the nuclear utility industry (Ref. 2) and can be used to assess and improve the performance of these and other similar rein-forced concrete structures.
Construction of earthen dams entails sequential place-ment and compaction of soil layers and the subsequent fill-up of the embanked reservoir. In the design of earthen dams, two potentially critical events must be considered: the rapid emptying (or drawdown) of the reservoir and the dynamic loading of an earthquake. The possibility of dam failure in these situations depends on the respective build-up and dissipation of the fluid pore pressure in the soil.
Space flight re-entry vehicles impart highly dynamic loads on the crew and/or payload during a water landing. To understand the behavior of the vehicle/payload system as it makes impact, a predictive framework that can simultaneously model the structure, the highly deformable landing medium (water or soil), and their interaction is required. The coupled Eulerian-Lagrangian (CEL) method in Abaqus/Explicit provides the means for capturing these complex physical phenomena.
Composite structures often have a higher capacity for ab-sorbing energy than their metal counterparts. The crush-ing behavior of composite materials is complex, and the inclusion of composite components in vehicles for crash protection can necessitate expensive experimental test-ing. The ability to computationally simulate the crushing response of composite structures can significantly shorten the product development cycle and reduce cost in the aerospace, automotive, and railway industries.
Bird strikes cost the United States aviation industry tens of millions of dollars annually in aircraft damage and schedule delays. Increasing the ability of the aircraft to resist bird strike induced damage is one part of an overall approach to mitigating this expense . Experimental bird strike testing is part of the certification process for certain aircraft component designs. If a subset of the tests can be replaced with computational simula-tion, the cost of the prototype testing can be reduced.
A mechanical system, such as aircraft landing gear, can have a large number of parts that interact in a complex nonlinear fashion. The challenge of simulating such a sys-tem lies not only in capturing the correct physical behavior but in using efficient analysis techniques. Different levels of modeling abstraction may be appropriate for different stages of the design process. Initial sizing and kinematics can be studied with a partially rigid representation, while final designs are more often analyzed with fully meshed flexible geometry.
Composite materials offer significant design advantages in the aerospace industry. High strength and light weight are the two most attractive features for aircraft and space vehicle designs. However, their complex material behav-ior makes analysis of these structures a significant chal-lenge, particularly in a high speed impact event. The ad-vanced composite modeling and industry leading simula-tion capabilities of Abaqus/Explicit make analysis of these challenging materials straightforward and allow accurate prediction of ballistic limit, damage and failure.
The use of composite materials in the aerospace industry is increasing. Composite materials offer a relatively high strength-to-weight ratio as well as the ability to create large, integrated structures. One composite component can replace 10 or more traditional metal parts, which can dramatically reduce manufacturing time and cost.
The Vernay VernaFlo® flow controls are custom-designed fluid flow management devices used in a wide range of applications and systems where consistent, reliable op-eration is essential. Elastomeric rubber components in these devices deform under the influence of upstream variations in fluid pressure. These deformations adjust the orifice diameter and help maintain a constant down-stream flow rate. In this Technology Brief the perform-ance of a custom VernaFlo® device is evaluated using the fully coupled fluid-structure interaction solution provided by the Abaqus co-simulation capability.
Engineering problems that involve the coupled response of a flowing fluid and a deforming structure constitute a broad class referred to as fluid-structure interaction (FSI). The interaction can be mechanical, thermal, or both. Many important problems involve some form of FSI, but the coupling effect is often ignored because of a lack of readily available solution technology. To address this limitation, Dassault Systèmes SIMULIA Corp. and Fluent, Inc. have partnered to provide a coupled solution capability.
As the maximum speed of bullet trains continues to increase, overheating and thermal deformation/stress on brake systems are going to be critical for emergency stops. Precise prediction of the maximum temperature is needed for the design of brake systems, especially for both discs and linings, where how to handle the high speed spinning of discs is the point of the heat/structure coupled analyses. Abaqus provides couple of potential methods but each one had critical shortcomings.
One key aspect for the design of fast and flexible steam turbine operation is thermal stresses arising during transient operation. If the stresses exceed the fatigue limits of the material, the lifetime of the steam turbine is shortened. Detailed finite element analysis is applied during design phase to assess the effect of transient temperature and stress profiles on the complex geometries. A significant amount of design effort is invested to determine the optimal process parameters for start-up (e.g.
Electrically operated high temperature furnaces and reactors are used in many industrial manufacturing processes such as sintering or single crystal growth in order to allow for the required process conditions. In view of their outstanding characteristics refractory metals are ideally suited as materials for the resistive heating elements. Nevertheless, significant and lifetime-limiting irreversible deformations of these elements can be frequently observed which are assumed to be caused by a combination of temperature expansion, electromagnetic forces, and high temperature creep effects.
Identication of fatigue cracks in turbo-machinery components is a vital but costly effort. This work focuses on nonlinearities in the response behavior resulting from the opening and closing of cracks that results in super-harmonic resonances due to harmonic excitations. Experimental results for a cracked cantilever beam are presented as well as the results from numerical simulations of an integrally bladed compressor disk FE model. Identication of sensitive vibration features is expected to contribute to the development of automated crack detection techniques for aircraft engine disks.
The modelling of welds is desirable to predict the distortion of components during manufacture, the position and magnitude of peak residual stresses and to predict metallurgical effects in specific regions. Welds are a complex modelling problem requiring both thermal and structural solutions. This has lead to the development of several weld-specific simulation packages and codes for finite element analysis packages. This paper describes the application of the newly developed Abaqus 2D Weld Modeller to simulate the residual stress field in ferritic weld test specimens.
Electric Boat’s design process involves evaluating the structural stability of ring-stiffened cylinder structures through finite element analyses to simulate a static pressure load. Each design revision of the cylinders must be evaluated to verify that the structure meets the required stress criteria for the static pressure load; any revision to geometry or material would require the design to be reevaluated. Additionally, it is critical that the weight of the structure is kept as light as possible while still satisfying all stress and deflection criteria.
The paper presents a numerical simulation of the drop test in a still water for the multi-component box structure. The complexity of the problem is in the strong fluid-structure interaction (FSI) between the box and the water free surface. The numerical simulation of the drop test is performed with two software tools: Abaqus and FlowVision through the direct coupling interface, which manipulates, on the Abaqus side the Lagrangian finite-element mesh and on the FlowVision side the Eulerian finite-volume mesh with sub grid geometry resolution.