Your Selections

Forming
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Committees

Events

Magazine

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Investigation of Fracture Behavior of Deep Drawn Automotive Part affected by Thinning with Shell Finite Elements

General Motors LLC-Hwawon Lee, Shengjian li, Hui-Min (Emmy) Huang, Parvath Police
  • Technical Paper
  • 2020-01-0208
To be published on 2020-04-14 by SAE International in United States
In the recent decades, tremendous effort has been made in automotive industry to reduce vehicle mass and development costs for the purpose of improving fuel economy and building safer vehicles that previous generations of vehicles cannot match.An accurate modeling approach of sheet metal fracture behavior under plastic deformation is one of the key parameters affecting optimal vehicle development process. FLD (Forming Limit Diagram) approach, which plays an important role in judging forming severity, has been widely used in forming industry, and localized necking is the dominant mechanism leading to fracture in sheet metal forming and crash events.FLD is limited only to deal with the onset of localized necking and could not predict shear fracture. Therefore, it is essential to develop accurate fracture criteria beyond FLD for vehicle development. To enhance the accuracy of crash simulations, forming results from stamping process are generally introduced to consider work hardening and thinning/thickening of a stamped part during the simulations. However, fracture criteria are only applied to the original design thickness, not the change in the gage thickness after…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Spatially Optimized Diffusion Alloys: A Novel Multi-Layered Steel Material for Exhaust Applications

Arcanum Alloys Inc.-Zachary Detweiler, David Keifer, Daniel Bullard
Tenneco Inc.-Adam Kotrba, Tony Quan, Winston Wei
  • Technical Paper
  • 2020-01-1051
To be published on 2020-04-14 by SAE International in United States
A novel Spatially Optimized Diffusion Alloy (SODA) material has been developed and applied to exhaust systems, which are an aggressive environment subject to high temperatures and loads, as well as excessive corrosion. Traditional stainless steels disperse chromium homogeneously throughout the material, with varying amounts ranging from 10% to 20% dependent upon its grade (e.g. 409, 436, 439, 441, and 304). SODA steels, however, offer layered concentrations of chromium, enabling an increased amount along the outer surface for much needed corrosion resistance and aesthetics. This outer layer, typically about 70μm thick, exceeds 20% of chromium concentration locally, but is less than 3% in bulk, offering selective placement of the chromium to minimize its overall usage. Since this layer is metallurgically bonded, it cannot delaminate or separate from its core, enabling durable protection throughout manufacturing processes and full useful life. The core material may be comprised of various grades, however, this study employs interstitial free steel (low carbon), which eases manufacturing operations, as it is more formable than stainless steel grades. The material and its manufacturing process…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Interactive Effects between Sheet Steel, Lubricants, and Measurement Systems on Friction

General Motors LLC-Jatinder P. Singh
University of Colorado Denver-Luis Rafael Sanchez Vega, Eduardo Corral
  • Technical Paper
  • 2020-01-0755
To be published on 2020-04-14 by SAE International in United States
This study evaluated the interactions between sheet steel, lubricant and measurement system under typical sheet forming conditions using a fixed draw bead simulator (DBS). Deep drawing quality mild steel substrates with bare (CR), electrogalvanized (EG) and hot dip galvanized (HDG) coatings were tested using a fixed DBS. Various lubricant conditions were targeted to evaluate the coefficient of friction (COF) of the substrate and lubricant combinations, with only rust preventative mill oil (dry-0 g/m2 and 1 g/m2), only forming pre-lube (dry-0 g/m2, 1 g/m2, and >6 g/m2), and a combination of two, where mixed lubrication cases, with incremental amounts of a pre-lube applied (0.5, 1.0, 1.5 and 2.0 g/m2) over an existing base of 1 g/m2 mill oil, were analyzed. The results showed some similarities as well as distinctive differences in the friction behavior between the bare material and the coatings. While friction on the bare substrate was higher than that of coated surfaces with lubrication, it was found to be significantly more tolerant to dry conditions. Stick-slip behavior was also studied as a measurement system…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Evaluations of Mechanical Properties of ABS Parts from Open-Source 3D Printers and Conventional Manufacturing

University of Kentucky-Jordan Garcia, Robert Harper, Coilin Bradley, John Schmidt, Y Charles Lu
  • Technical Paper
  • 2020-01-0229
To be published on 2020-04-14 by SAE International in United States
3D printing is a revolutionary manufacturing method that allows the productions of engineering parts almost directly from modeling software on a computer. With 3D printing technology, future manufacturing could become vastly efficient. However, the procedures used in 3D printing differ substantially among the printers and from those used in conventional manufacturing. The objective of the present work was to comprehensively evaluate the mechanical properties of engineering products fabricated by 3D printing and conventional manufacturing. Three open-source 3D printers, i.e., the Flash Forge Dreamer, the Tevo Tornado, and the Prusa, were used to fabricate the identical parts out of the same material (acrylonitrile butadiene styrene). The parts were printed at various positions on the printer platforms and then tested in bending. Results indicate that there exist substantial differences in mechanical responses among the parts by different 3D printers. Specimens from the Prusa printer exhibit the best elastic properties while specimens from the Flash Forge printer exhibit the greatest post-yield responses. There further exist noticeable variations in mechanical properties among the parts that were fabricated by the…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Multi-Objective Optimization of Sheet Metal-Polymer Hybrids Manufactured by the Integrated Process of Deep Drawing-Back Injection Molding

Clemson University (CUICAR)-Saeed Farahani, Farzam Malmir, Deepak Aggarwal, Srikanth Pilla
  • Technical Paper
  • 2020-01-0622
To be published on 2020-04-14 by SAE International in United States
Lightweight constructions can no longer be achieved solely through material substitution. To stay competitive, design parameters and manufacturing technologies should be taken into consideration as well. The integrated process of Deep Drawing-Back Injection Molding (DDBIM) is such an advanced process in which the sheet metal blank is first deformed by tool movement and then calibrated to the shape of the cavity using polymer melt pressure during the injection process. Therefore, the traditional processes of sheet metal forming, and injection molding are combined into one step operation, thus reducing the process steps and required machinery. Even though the process has its own challenges, the best combination of weight, performance, cost, and quality can be achieved by defining a multi-objective optimization problem with respect to the influencing design parameters. This study aims to optimize the various parameters of the sheet metal-polymer structure using Taguchi-based Grey optimization. A system of orthogonal arrays is used as the design of experiment (DOE) in order to evenly distribute the design variables in the design space. Moreover, S/N ratio studies are employed…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Innovative Passive Exhaust Valve Improves Sound Quality and Reduces Muffler Volume without Backpressure Penalty

Tenneco, Inc.-Adam Kotrba, Stephen Thomas, Gabriel Ostromecki, Asela Benthara, Nicholas Morley
  • Technical Paper
  • 2020-01-0410
To be published on 2020-04-14 by SAE International in United States
Exhaust systems traditionally require a specific amount of muffler volume to reduce sound levels appropriately. However, as hybridization evolves, the packaging area becomes smaller, reducing available muffler space and requiring alternative solutions to attenuate exhaust sound with less volume. Passive exhaust valves are a key solution, leveraging the physics of the exhaust (flow, temperature, and pressure) to cycle the valve. Passive exhaust valves typically operate in a closed position under low-flow conditions (low engine speeds and loads), which helps to reduce low-frequency boom, moderately increasing backpressure when it is not detrimental to engine efficiency. Conversely, under higher engine speed and load operating conditions, when exhaust flow increases and backpressure is critical to achieve desired power output, the passive valve opens to reduce its impact. Such valves are often positioned within the muffler, fully immersed and exposed to exhaust heat, humidity, and corrosion, as well as vibrations from road and engine loads. A next-generation passive valve is detailed in this paper, highlighting its operating advantages, including compact size (fits inside mufflers), low mass (all sheet metal…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

DEVELOPMENT OF AN EPOXY CARBON FIBER REINFORCED ROOF FRAME USING THE HIGH PRESSURE RESIN TRANSFER MOLDING (HP-RTM) PROCESS

Hexion Inc.-Cedric A. Ball, Stephen Greydanus, Ian Swentek, Kameswara Rao Nara
  • Technical Paper
  • 2020-01-0773
To be published on 2020-04-14 by SAE International in United States
Composites technology for the automotive market continues to advance rapidly. Increasing knowledge of composite design, simulation tools, new materials and process equipment are all contributing to make composites better performing and more affordable for mass-produced vehicles. In particular, the high pressure resin transfer molding (HP-RTM) and related liquid compression molding (LCM) processes are enabling manufacturers to produce complex composite parts at shorter and shorter cycle times. This paper describes the development of an epoxy carbon fiber roof frame targeted for future vehicle production. Several composite processes were considered for the roof frame. The case illustrates that when the (product) design, material and process are considered together, a high-performing, cost-efficient part can be produced. The resulting carbon fiber roof frame met all OEM performance requirements and economic targets while weighing 44% less than the original design in magnesium and 32% less on the overall assembly. The part was the first HP-RTM part successfully demonstrated in North America and stands as a model for future lightweighting developments. Of equal significance, the development process for the part involved…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Hybrid Forming - A Novel Manufacturing Technique for Metal-LFT Structural Parts

University of Siegen-Daniel Heidrich, Tobias Kloska, Xiangfan Fang
  • Technical Paper
  • 2020-01-0235
To be published on 2020-04-14 by SAE International in United States
Hybrid structural parts combining aluminum or steel sheets with long glass fiber reinforced thermoplastics (LFT) offer a great opportunity to reduce component weight for automotive applications. But due to high manufacturing cost, metal-LFT hybrid components are still scarcely used in automotive large-scale production. Thus in this work a novel cost- and time efficient manufacturing process for simultaneous metal sheet forming and compression molding of long fiber reinforced thermoplastics to manufacture automotive lightweight components is presented. In this manufacturing process, which is referred to as “Hybrid forming”, a fiber reinforced thermoplastic melt is used as a forming medium in the manner of well-known hydroforming processes. After forming the metal sheet by polymer melt in combination with the rigid die, the melt solidifies and forms a local reinforcement structure in the hybrid component. Since the metal sheet is pre-coated with a bonding agent prior to the forming process, a firmly bonded connection between metal and LFT can be achieved.For proof of concept a longitudinal control arm in a multi-link rear axle is chosen. By utilizing Hybrid forming…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Multi-Material Topology Optimization Considering Manufacturing Constraints

General Motors of Canada Company-Manish Pamwar, Balbir Sangha
Queen's University-Vishrut Shah, Kiarash Kashanian, Il Yong Kim
  • Technical Paper
  • 2020-01-0628
To be published on 2020-04-14 by SAE International in United States
The field of topology optimization (TO) has been evolving rapidly, notably due to the emergence of multi-material topology optimization (MMTO) algorithms. These developments follow the establishment of TO tools within industry, which has been accelerated and promoted through the introduction of various manufacturing constraints within algorithms. The integration of manufacturing constraints within MMTO is critical for promoting industry usage and adoption of these new software algorithms, as current usage of MMTO is dissuaded by the typically complex design solutions.The presented MMTO implementation is an extension of classical single-material topology optimization (SMTO). The TO problem is expanded to consider both material existence and selection, solid isotropic material with penalization (SIMP) is utilized for material interpolation. The method of moving asymptotes (MMA) has been integrated into MMTO as the optimization algorithm as it can handle large-scale problems with many design variables.A design variable mapping system has been incorporated into MMTO, which determines element groups based on symmetry or extrusion manufacturing constraints. The design variables of the group elements are constrained to equivalent values, resulting in either extruded…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Parametric Study of Spring-Back Effects in Deep Drawing by Design of Experiment

University of Detroit Mercy-Ramzi S. Youssif, Mostafa Mehrabi
  • Technical Paper
  • 2020-01-0750
To be published on 2020-04-14 by SAE International in United States
Deep drawing is a sheet metal forming process in which metal blank is radially drawn into a forming die by the mechanical action of the punch. Dimensional tolerances and their variations are important aspects of quality control issues in this forming operation. In this regard, the spring-back effect is an inherent phenomenon that directly affects the final dimensions of the part produced. This research work is focused on analysis and control of spring-back in deep drawing processes. It is mainly focused on design and implementation/simulation of control strategies to minimize that. In this regard, the impact of various process parameters such as lubrication, punch speed, punch and die nose radius, and blank holding force is studied through design of experiment methodology. In particular, this study is focused on the design and development of various control strategies to minimize spring back in this process. An experimental set up is designed and developed to facilitate this research. This paper presents some of the experimental results obtained from this study.