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A myriad of topology optimization tools exist today in the market that use automated under-the-hood structural simulations. All the user needs is to provide is the current shape of the part, or the maximum space that the part is allowed to occupy, and the maximum loads that it will experience. Though this technology has existed for over 25 years, recent advances in Additive Manufacturing (AM) have now enabled fabrication of hitherto-infeasible parts, both quickly and inexpensively. A quick cursory literature search on successful implementation of topology optimization reveals that a majority of the attention has been focused on structural components and assemblies subjected to known service load(s) [1,2,3]. Therein lies one of the disadvantages experienced in the state-of-the-art today, especially for the military industry.

A full-system, end-to-end blast modeling and simulation of vehicle underbody buried blast events typically includes detailed modeling of soil, high explosive (HE) charge and air. The complex computations involved in these simulations take days to just capture the initial 50-millisecond blast-off phase, and in some cases, even weeks. The single most intricate step in the buried blast event simulation is in the modeling of the explosive loading on the underbody structure from the blast products; it is also one of the most computationally expensive steps of the simulation. Therefore, there is significant interest in the modeling and simulation community to develop various methodologies for fast running tools to run full simulation events in quicker turnarounds of time.

In this paper, the capability of three methods of modelling detonation of high explosives (HE) buried in soil viz., (1) coupled discrete element & particle gas methods (DEM-PGM) (2) Structured - Arbitrary Lagrangian-Eulerian (S-ALE), and (3) Arbitrary Lagrangian-Eulerian (ALE), are investigated. The ALE method of modeling the effects of buried charges in soil is well known and widely used in blast simulations today [1]. Due to high computational costs, inconsistent robustness and long run times, alternate modeling methods such as Smoothed Particle Hydrodynamics (SPH) [2, 9] and DEM are gaining more traction. In all these methods, accuracy of the analysis relies not only on the fidelity of the soil and high explosive models but also on the robustness of fluid-structure interaction. These high-fidelity models are also useful in generating fast running models (FRM) useful for rapid generation of blast simulation results of acceptable accuracy.

Assessing the dynamic performance of multilayer plates subjected to impulsive loading is of interest for identifying configurations that either absorb energy or transmit the energy in the transverse directions, thereby mitigating the through-thickness energy propagation. A reduced-order modeling approach is presented in this paper for rapidly evaluating the structural dynamic performance of various multilayer plate designs. The new approach is based on the reverberation matrix method (RMM) with the theory of generalized rays for fast analysis of the structural dynamic characteristics of multilayer plates. In the RMM model, the waves radiated from the dynamic load are reflected and refracted at each interface between layers, and the waves within each layer are transmitted with a phase lag. These two phenomena are represented by the global scattering matrix and the global phase matrix, respectively.

This paper presents a computational investigation of the validity of eddy current testing (ECT) for defects embedded in steel using parametrically designed defects. Of particular focus is the depths at which defects can be detected through ECT. Building on this we characterize interior defects by parametrically describing them and then examining the response fields through measurement. Thereby we seek to establish the depth and direction of detectable cracks. As a second step, we match measurements from eddy current excitations to computed fields through finite element optimization. This develops further our previously presented methods of defect characterization. Here rough contours of synthesized shapes are avoided by a novel scheme of averaging neighbor heights rather than using complex Bézier curves, constraints and such like. This avoids the jagged shapes corresponding to mathematically correct but unrealistic synthesized shapes in design and nondestructive evaluation.

It is of considerable interest to developers of military vehicles, in early phases of the concept design process as well as in Analysis of Alternatives (AoA) phase, to quickly predict occupant injury risk due to under-body blast loading. The most common occupant injuries in these extremely short duration events arise out of the very high vertical acceleration of vehicle due to its close proximity to hot high pressure gases from the blast. In a prior study [16], an extensive parametric study was conducted in a systematic manner so as to create look-up tables or automated software tools that decision-makers can use to quickly estimate the different injury responses for both stroking and non-stroking seat systems in terms of a suitable blast load parameter. The primary objective of this paper is to quantitatively evaluate the accuracy of using such a tool in lieu of building a detailed model for simulation and occupant injury assessment.

Occupant head impact simulations on automotive instrument panels (IP) are routinely performed as part of an integrated design process during the course of IP development. Based on the requirements (F/CMVSS, ECE), head impact zones on the IP are first established, which are then used to determine the various “hit” locations to be tested/analyzed. Once critical impact locations are identified, CAE simulations performed which is a repetitive process that involves computing impact angles, positioning the rigid head form with an assigned initial velocity and defining suitable contacts within the finite element model. A commercially available CAE process automation tool was used to automate these steps and generate a head impact simulation model. Once the input model is checked for errors by the automated process, it can be submitted to a solver without any user intervention for analysis and report generation.

Interior compartment doors are required by Federal Motor Vehicle Safety Standard (FMVSS) 201, to stay closed during physical head impact testing, and when subjected to specific inertia loads. This paper defines interior compartment doors, and shows examples of several different latches designed to keep these doors closed. It also explores the details of the requirements that interior compartment doors and their latches must meet, including differing requirements from automobile manufacturers. It then shows the conventional static method a supplier uses to analyze a latch and door system. And, since static calculations can't always capture the complexities of a dynamic event, this paper also presents a case study of one particular latch and door system showing a way to simulate the forces experienced by a latch. The dynamic simulation is done using Finite Element Analysis and instrumentation of actual hardware in physical tests.

Visteon has developed a CAE procedure to qualify instrument panel (IP) products under the vehicle key life test environments, by employing a set of CAE simulation and durability techniques. The virtual key life test method simulates the same structural configuration and the proving ground road loads as in the physical test. A representative dynamic road load profile model is constructed based on the vehicle proving ground field data. The dynamic stress simulation is realized by employing the finite element transient analysis. The durability evaluation is based on the dynamic stress results and the material fatigue properties of each component. The procedure has helped the IP engineering team to identify and correct potential durability problems at earlier design stage without a prototype. It has shown that the CAE virtual key life test procedure provides a way to speed up IP product development, to minimize prototypes and costs.

Occupant knee impact simulations are performed in the automotive industry as an integrated design process during the course of instrument panel (IP) development. All major automakers have different categories of dynamic testing methods as part of their design process in validating their designs against the FMVSS 208 requirement. This has given rise to a corresponding number of knee impact simulations performed at various stages of product development. This paper investigates the advantages and disadvantages of various types of these knee impact simulations. Only the knee load requirement portion of the FMVSS208 is considered in this paper.

GENPAD® is a knowledge-based, three-dimensional modeling computer tool developed by Visteon to create occupant-friendly interiors. GENPAD quickly and easily produces zones to evaluate ergonomic aspects of vehicle interiors such as reach, clearance, vision, and reflection. These zones are produced from automated design studies based on experience and engineering standards accepted by the automotive industry. Without GENPAD, a single study requires an experienced engineer 4-6 hours to complete. Multiple studies require several engineers weeks to perform. The methods used are also error-prone due to complex instructions. To overcome these challenges, GENPAD provides over 50 ergonomic packaging studies that produce accurate results in minutes, not weeks, every time.

The ability to quickly design new vehicles with optimal crashworthiness has long been a goal of automotive manufacturers and Tier 1 suppliers alike. This paper takes steps towards that goal by automating manual design iterations. The crashworthiness of an instrument panel was optimized using LS-OPT. In one design experiment, optimizing the gauges of non-styled parts in the instrument panel reduced the simulated force in a Bendix test setup by around 30%. In a second design experiment, optimizing the shape of non-styled parts in the instrument panel with a parametric preprocessor enhanced the simulated crashworthiness by around 20%. In a third design experiment, the design space was increased and an additional 7% improvement in simulated crashworthiness was found. The designs were generated several times faster and were less expensive to evaluate than with previous manual methods.

The increased focus on cost reduction remains one of the major interests of the global automotive industry in general and of interior systems suppliers in particular. This emphasis is heightened due to globalization and expansion of automotive OEMs in their product line, so that they may participate and compete in lower priced niche markets. The cost of plastic components in the automotive interior is about $500 per vehicle, of which a significant portion is material cost alone. Low cost materials hitherto not considered traditional autoplastics are making inroads due to the advancements in the interior component manufacturing technology. This paper describes the process of material selection for IPs using Computer Aided Engineering (CAE) tools to evaluate their functional requirements, such as noise vibration and harshness (NVH), sunload deformations, and safety performance.

This paper highlights the application of design optimization in reducing product manufacturing cost without compromising product performance. By using a topology optimization method, the manufacturing cost of a clam shell has been reduced by approximately one-third, while maintaining the NVH performance of the steering column that is connected to the instrument panel (IP) through the clam shell. Two different optimization approaches and two different topological weld deployments are investigated. It is found that a fully-deployed seam weld approach with automatic optimization provides the best design results.

During the conceptual design stages of an instrument panel (IP) structure, various alternatives in architecture need to be evaluated. This entails being able to obtain a quick assessment of how the designs roughly compare in structural performance. The current climate of reduced cycle times dictates that quick and inexpensive CAE techniques be employed for this purpose. This paper describes the background of a design process in which Computer Aided Engineering (CAE) models, fully associative with the underlying 3D solid model, are rapidly generated for use in structural vibration, thermal and crash analysis.