scholarly journals Crash Characteristics of Partially Quenched Curved Products by Three-Dimensional Hot Bending and Direct Quench

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1322
Author(s):  
Atsushi Tomizawa ◽  
Sanny Soedjatmiko Hartanto ◽  
Kazuo Uematsu ◽  
Naoaki Shimada
Keyword(s):  
Energy Absorption ◽  
Three Dimensional ◽  
Crash Test ◽  
Initial Stage ◽  
Automotive Parts ◽  
Fundamental Research ◽  
Vehicle Technologies ◽  
Crash Characteristics ◽  
Crash Tests ◽  
Direct Quench

Recently, improvement of hybrid and electric vehicle technologies, equipped with batteries, continues to solve energy and environmental problems. Lighter weight and crash safety are required in these vehicles body. In order to meet these requirements, three-dimensional hot bending and direct quench (3DQ) technology, which enables to form hollow tubular automotive parts with a tensile strength of 1470 MPa or over, has been developed. In addition, this technology enables to produce partially quenched automotive parts. In this study, the crash characteristics of 3DQ partially quenched products were investigated as the fundamental research of the design for improving the energy absorption. Main results are as follows: (1) for partially quenched straight products in axial crash test, buckling that occurs at nonquenched portion can be controlled; (2) for the nonquenched conventional and overall-quenched curved products, buckling occurs at the bent portion at the initial stage in axial crash tests, and its energy absorption is low; (3) by optimizing partially quench conditions, buckling occurrence can be controlled; and (4) In this study, the largest energy absorption was obtained from the partially quenched curved product, which was 84.6% larger than the energy absorption of the conventional nonquenched bent product in crash test.

scholarly journals Fault-tolerant elastic–plastic lattice material

2019 ◽  
Vol 378 (2162) ◽  
pp. 20190107 ◽  
Author(s):  
Michael Ryvkin ◽  
Viacheslav Slesarenko ◽  
Andrej Cherkaev ◽  
Stephan Rudykh
Keyword(s):  
Energy Absorption ◽  
Fault Tolerant ◽  
Three Dimensional ◽  
Uniaxial Tensile ◽  
Elastoplastic Material ◽  
Beam Elements ◽  
Initial Stage ◽  
Final Failure ◽  
Thin Beams ◽  
Beam Lattice

The paper describes a fault-tolerant design of a special two-dimensional beam lattice. The morphology of such lattices was suggested in the theoretical papers (Cherkaev and Ryvkin 2019 Arch. Appl. Mech. 89 , 485–501; Cherkaev and Ryvkin 2019 Arch. Appl. Mech. 89 , 503–519), where its superior properties were found numerically. The proposed design consists of beam elements with two different thicknesses; the lattice is macro-isotropic and stretch dominated. Here, we experimentally verify the fault-tolerant properties of these lattices. The specimens were three-dimensional-printed from the VeroWhite elastoplastic material. The lattice is subjected to uniaxial tensile loading. Due to its morphology, the failed beams are evenly distributed in the lattice at the initial stage of damage; at this stage, the material remains intact, preserves its bearing ability, and supports relatively high strains before the final failure. At the initial phase of damage, the thinner beams buckle; then another group of separated thin beams plastically yield and rupture. The fatal macro-crack propagates after the distributed damage reaches a critical level. This initial distributed damage stage allows for a better energy absorption rate before the catastrophic failure of the structure. The experimental results are supported by simulations which confirm that the proposed fault-tolerant material possesses excellent energy absorption properties thanks to the distributed damage stage phenomenon. This article is part of the theme issue ‘Modelling of dynamic phenomena and localization in structured media (part 2)’.

Weight Reduction of the Automotive Body by using Three-Dimensional Hot Bending and Direct Quench (3DQ) Technology

2015 ◽  
Vol 84 (7) ◽  
pp. 514-518
Author(s):  
Ryuji HAMADA ◽  
Hiroki FUJIMOTO ◽  
Masahiro OGAWA ◽  
Naoaki SHIMADA
Keyword(s):  
Weight Reduction ◽  
Three Dimensional ◽  
Automotive Body ◽  
Direct Quench

Numerical and experimental investigation for enhancing the energy absorption capacity of the novel three-dimensional printed sandwich structures

2021 ◽  
pp. 146442072199749
Author(s):  
H Geramizadeh ◽  
S Dariushi ◽  
S Jedari Salami
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
The Novel ◽  
Energy Absorption Capacity ◽  
Fused Deposition ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Vertical Walls

The current study focuses on designing the optimal three-dimensional printed sandwich structures. The main goal is to improve the energy absorption capacity of the out-of-plane honeycomb sandwich beam. The novel Beta VI and Alpha VI were designed in order to achieve this aim. In the Beta VI, the connecting curves (splines) were used instead of the four diagonal walls, while the two vertical walls remained unchanged. The Alpha VI is a step forward on the Beta VI, which was promoted by filleting all angles among the vertical walls, created arcs, and face sheets. The two offered sandwich structures have not hitherto been provided in the literature. All models were designed and simulated by the CATIA and ABAQUS, respectively. The three-dimensional printer fabricated the samples by fused deposition modeling technique. The material properties were determined under tensile, compression, and three-point bending tests. The results are carried out by two methods based on experimental tests and finite element analyses that confirmed each other. The achievements provide novel insights into the determination of the adequate number of unit cells and demonstrate the energy absorption capacity of the Beta VI and Alpha VI are 23.7% and 53.9%, respectively, higher than the out-of-plane honeycomb sandwich structures.

Finite Element Simulation of a Strong-Post W-Beam Guardrail System

SIMULATION ◽  
2002 ◽  
Vol 78 (10) ◽  
pp. 587-599 ◽  
Author(s):  
Ali O. Atahan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Full Scale ◽  
Nonlinear Finite Element ◽  
Crash Test ◽  
Original Design ◽  
Dynamic Interactions ◽  
Crash Testing ◽  
Element Simulation ◽  
Test Requirements

Computer simulation of vehicle collisions has improved significantly over the past decade. With advances in computer technology, nonlinear finite element codes, and material models, full-scale simulation of such complex dynamic interactions is becoming ever more possible. In this study, an explicit three-dimensional nonlinear finite element code, LS-DYNA, is used to demonstrate the capabilities of computer simulations to supplement full-scale crash testing. After a failed crash test on a strong-post guardrail system, LS-DYNA is used to simulate the system, determine the potential problems with the design, and develop an improved system that has the potential to satisfy current crash test requirements. After accurately simulating the response behavior of the full-scale crash test, a second simulation study is performed on the system with improved details. Simulation results indicate that the system performs much better compared to the original design.

scholarly journals Numerical Simulation of Temperature Distribution in the Glass Fiber Epoxy Composites during Microwave Curing

2018 ◽  
Vol 206 ◽  
pp. 03001
Author(s):  
X Zhang ◽  
X L Chang ◽  
R L Ma ◽  
L Zhang ◽  
X D Chen ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Glass Fiber ◽  
Three Dimensional ◽  
Coupled Model ◽  
Curing Process ◽  
Epoxy Ring ◽  
Microwave Curing ◽  
Composite Ring ◽  
Initial Stage ◽  
Field Temperature

A three-dimensional coupled model of electromagnetic field, temperature field and curing degree field was established. Based on this model, the simulation of microwave curing process of glass fiber epoxy ring was realized, and the temperature distribution at different time was obtained. Numerical results indicate that the temperature difference within the composite ring is mainly formed in the initial stage during microwave curing.

Observation of Growth Front on the Initial Stage of Goss Abnormally-Growing Grain in Fe-3%Si Steel

2013 ◽  
Vol 753 ◽  
pp. 307-310
Author(s):  
Kyung Jun Ko ◽  
Jong Tae Park ◽  
Chan Hee Han
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Three Dimensional ◽  
Secondary Recrystallization ◽  
Growth Front ◽  
Very High Frequency ◽  
Grain Boundary Mobility ◽  
Initial Stage ◽  
The Matrix

During abnormal grain growth, a few Goss grains grow exclusively fast and consume the matrix grains. The Goss abnormally-growing grain (AGG) has peculiar features which are irregular grain boundaries and very high frequency of peninsular grains nearby the growth front of AGG and island grains trapped inside AGG. These features might provide a clue for clarifying the mechanism of Goss AGG. The experimentally-observed microstructural feature and grain boundary characterization of Goss were approached by the solid-state wetting mechanism. In this study, observing the three-dimensional wetting morphology in serial section images of Goss AGG by EBSD, we report some direct microstrucrual evidence supporting solid-state wetting mechanism for Goss AGG. The solid-state wetting mechanism for the evolution of the Goss AGG in Fe-3%Si steel explains the microstructural features evolved during secondary recrystallization, which cannot be approached by the conventional theories based on the grain boundary mobility.

Comparison of Different Methods for the Evaluation of Cavitation Damaged Surfaces

2005 ◽  
Author(s):  
B. Bachert ◽  
G. Ludwig ◽  
B. Stoffel ◽  
S. Baumgarten
Keyword(s):  
Mass Loss ◽  
White Light ◽  
Cavitation Erosion ◽  
Evaluation Method ◽  
Three Dimensional ◽  
Special Device ◽  
Test Rig ◽  
Rotating Disc ◽  
White Light Interferometer ◽  
Initial Stage

The experimental data which will be presented in this paper are the results of the comparison between different methods for evaluating damaged surfaces by cavitation erosion. The different methods are partly working in the initial stage of cavitation erosion and partly at developed cavitation erosion, where mass loss occurs. The used test rig consists basically of a rotating disc with a diameter of 500 mm on which four holes are located. Each hole generates a cavitation zone while the disc is rotating. The test objects are material specimens made of copper. Copper was used as test material in respect to reasonable durations for the tests. The specimen can be implemented in the casing of the test rig directly across the rotating disc on the diameter where the holes are located. This rotating disc test rig generates a very aggressive type of cavitation, so that mass loss, of course depending on the tested material, will appear after relatively short durations. Also the initial stage of cavitation erosion can be observed. The used test rig is very interesting regarding the possibility to apply different measuring techniques to characterize the erosive aggressiveness of cavitation. These techniques are at first the so-called Pitcount-Method, which allows investigations of cavitation erosion in the initial stage. The second one is an acoustic method, which is based on a structure-borne noise sensor and a specially developed signal processing system. The third method is the measuring of mass loss of the material specimen after several time steps. With the help of a CCD-camera and special digital image processing software, images of different cavitation conditions were recorded. The information obtained from these images should serve as support for the evaluation of the other used methods. After the evaluation with the above mentioned methods, the specimens were evaluated with a special device which works with the help of a white light interferometer. With this evaluation method three-dimensional information can be obtained in respect to the actually eroded volume of the specimens. With this information the lost mass of the specimens could be calculated directly. Especially the comparison of the results obtained from the Pitcount-Method, which is a two-dimensional evaluation method, and the three-dimensional results of the white light interferometer is an important point of the work within this paper.

A Sub-System Test Methodology for Simulating EEVC Side Impact

2000 ◽  
Author(s):  
Krishnakanth Aekbote ◽  
Srinivasan Sundararajan ◽  
Joseph A. Prater ◽  
Joe E. Abramczyk
Keyword(s):  
Full Scale ◽  
Test Method ◽  
Side Impact ◽  
Vehicle Body ◽  
Crash Test ◽  
Vehicle Performance ◽  
Test Methodology ◽  
Supporting Frame ◽  
The Impact ◽  
Crash Tests

Abstract A sled based test method for simulating full-scale EEVC (European) side impact crash test is described in this paper. Both the dummy (Eurosid-1) and vehicle structural responses were simulated, and validated with the full-scale crash tests. The effect of various structural configurations such as foam filled structures, material changes, rocker and b-pillar reinforcements, advanced door design concepts, on vehicle performance can be evaluated using this methodology at the early stages of design. In this approach, an actual EEVC honeycomb barrier and a vehicle body-in-white with doors were used. The under-hood components (engine, transmission, radiator, etc.), tires, and the front/rear suspensions were not included in the vehicle assembly, but they were replaced by lumped masses (by adding weight) in the front and rear of the vehicle, to maintain the overall vehicle weight. The vehicle was mounted on the sled by means of a supporting frame at the front/rear suspension attachments, and was allowed to translate in the impact direction only. At the start of the simulation, an instrumented Eurosid-1 dummy was seated inside the vehicle, while maintaining the same h-point location, chest angle, and door-to-dummy lateral distance, as in a full-scale crash test. The EEVC honeycomb barrier was mounted on another sled, and care was taken to ensure that weight, and the relative impact location to the vehicle, was maintained the same as in full-scale crash test. The Barrier impacted the stationary vehicle at an initial velocity of approx. 30 mph. The MDB and the vehicle were allowed to slide for about 20 inches from contact, before they were brought to rest. Accelerometers were mounted on the door inner sheet metal and b-pillar, rocker, seat cross-members, seats, and non-struck side rocker. The Barrier was instrumented with six load cells to monitor the impact force at different sections, and an accelerometer for deceleration measurement. The dummy, vehicle, and the Barrier responses showed good correlation when compared to full-scale crash tests. The test methodology was also used in assessing the performance/crashworthiness of various sub-system designs of the side structure (A-pillar, B-pillar, door, rocker, seat cross-members, etc.) of a passenger car. This paper concerns itself with the development and validation of the test methodology only, as the study of various side structure designs and evaluations are beyond the scope of this paper.

The Affordances of 3D Virtual Learning Environments

2019 ◽  
pp. 106-123
Author(s):  
Hisae Matsui ◽  
Terence C. Ahern
Keyword(s):  
Virtual Environments ◽  
Learning Environments ◽  
Native Speakers ◽  
Three Dimensional ◽  
Virtual Learning ◽  
Virtual Learning Environments ◽  
Initial Stage ◽  
American Students ◽  
3D Virtual Learning Environments

The purpose of this chapter is to examine participants' perceived affordances of three-dimensional virtual learning environments (3D VLEs) in developing interpersonal emotional connections with their partners during the initial stage of the virtual exchange. To fulfill the purpose, two Japanese and two American students were paired and participated in sessions within two differently designed virtual environments using the same 3D virtual application. The results indicate that the participants tend to find avatars useful as a cue that helps in recalling previous conversations and in avoiding long silences. Additionally, the affordances of the 3D VLEs heightened the experience of co-presence. However, for non-native speakers, this experience also created increased anxiety. Finally, the results show the affordances affected the participants much more strongly during the first several sessions but were mitigated by other factors as the sessions continued.

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