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is, the deformation energy) of the side
Overlay test and simulation Force intrusion
impact beams were measured and
evaluated. 30
The wood concept side impact beam Force [kN] 20
has a sandwich layup consisting of birch 10
veneer layers, viscose fabric layer and 0
0 50 100 150 200 250 300
cardboard honeycomb. The idea of the Instrusion [mm]
layup is to provide a high initial stiff- T = 28 ms
Test Simulation
ness, due to the high bending moment
of inertia. After roughly 50 mm impactor FIGURE 4 Validation of the wood-based side impact beam: comparison of test and simulation
way, the honeycomb shall commence (© WoodCar)
buckling, and thus gradually reduce the
height of the side impact beam. In that
way, the bending side impact beam is costs and increase of resistance against phase by reducing component and struc-
gradually converted to a “tensile cable,” moisture. tural mass.
which mainly can transfer axial loads.
Wood and wood veneers show a high REFERENCES
LIFE CYCLE ASSESSMENT
tensional strength but fail brittle. The [1] Friedrich, E. H. (ed.): Leichtbau in der Fahr-
zeug technik. 1 st edition, Wiesbaden: Springer
viscose fabric layers shall prevent brittle Parallel to the technical work on the side
Vieweg, 2013
failure, splintering of the entire beam. impact beam a Life Cycle Assessment [2] Braess, H.-H.; Seiffert, U.: Vieweg-Handbuch
The wood concept side impact beam (LCA) was conducted in the WoodCar Kraftfahrzeugtechnik. 7 th edition, Wiesbaden:
was quasi-statically and dynamically research project [10]. The main impact Springer Vieweg, 2013
[3] Duflou, J. R.; Deng, Y.; Van Acker, K.; Dewulf,
tested for validation, using the devel- categories that were considered are the
W.: Do Fiber-reinforced Polymer Composites Provide
oped test rig to ensure comparability of Global Warming Potential (GWP) and Environmentally Benign Alternatives? A Life-cycle
different concepts. Testing showed that the Cumulative Energy Demand (CED). Assessment-based Study. In: MRS Bulletin 37
the wood-based demonstrator was able Two databases were used, namely Sima- (2012), No. 4, pp. 374-382
[4] Herbeck, L.; Lang, M.: Die Industrialisierung der
to absorb almost the same amount of Pro and EcoInvent. In the LCA a vehicle
Composites-Produktion. Vortrag, 2. VDI-Fachkon-
kinetic en ergy as the baseline beam with a weight of 2000 kg, a life span of gress Leichtbau für den Automobilbau, Stuttgart,
made from high strength steel (1845 150.000 km and an internal combustion July 10, 2012
[5] Shah, D. U.: Developing Plant Fibre Composites
versus 1884 J), FIGURE 3. The current engine (SI engine) was assumed.
for Structural Applications by Optimising Composite
wood concept side impact beam lacked The LCA separates between the pro- Parameters: a Critical Review. In: Journal of Materi-
the high initial stiffness of the steel- duction phase, the use phase and the als Science 48 (2013), No. 18, pp. 6083-6107
based side impact beam, which in turn end-of-life stage. The LCA clearly showed [6] Coquel, M.: Fiber-Patch-Preforming [FPP] Opti-
mised CFRP Design and Efficient Production. Vor-
leads to increased intrusion during the that the highest proportion of the GWP
trag, Innovationstag Composite Simulation, CFK Val-
test process. and the CED are due to the use phase, ley Stade, May 15, 2014
Prior to the test, a simulation model this is while the vehicle is in service. [7] Faruk, O.; Bledzki, A. K.; Fink, H.-P.; Sain, M.:
of the demonstrator was created, which This clearly shows that “natural” materi- Progress Report on Natural Fiber Reinforced Com-
posites. In: Macromolecular Materials and Engineer-
was found to match remarkably well als in automotive industry are only “eco-
ing 299 (2014), No. 1, pp. 9-26
with the tests in terms of force-displace- logic” when they can outperform con- [8] IPCC: Special Report Global Warming of 1.5 ºC.
ment response. This good correlation ventional material in terms of weight. SR1.5, October 8, 2018, online: www.ipcc.ch/sr15/,
access: September 5, 2019
between test and simulation provides
[9] Jost, T.; Müller, U.; Feist, F.: Holzverbundwerk-
the basis for further development of the stoffe im Automobilbau der Zukunft? – Grund-
CONCLUSION
demonstrator in a FE simulation environ- voraussetzung: Crashsimulation von Holzkompo-
ment, FIGURE 4. [9] In summary, the use case side impact nenten. In: Konstruktion, 2018, No. 10, pp. 74-82
[10] WoodCar (Wood – Computer Aided Research):
The use-case study is limited to beam shows that statically and dynami-
Motivation and Goals. Online: www.woodcar.eu/
the side-impact load cases, mentioned cally highly loaded components made of motivation.html, access: September 20, 2019
before. The premise of these use-cases wood composites can be produced with
was to proof that a wood-based side low mass and the same energy absorp-
impact beam can be heavily deformed, tion capability. Furthermore, it rep-
without facture and thus without injury resents that the predictive ability of the
risk for the occupants due to splinters, developed virtual methods and models
allowing for high tensional strength at of wood concept components is very
the later stage of tests, in order to finally good in static and crash load cases.
absorb a similar amount of energy as the Wood as a design material can con-
baseline model and at a total weight of tribute to meet ecologic and social aims. THANKS
1000 g. As for now, these challenges are It can help in reducing the CO 2 footprint
all met. On going research and develop- through storage and substitution effects. The authors would like to thank the Austrian Promotion
ment work will address the following Furthermore, as a lightweight design Agency (FFG), the Styrian Business Promotion (SFG)
issues: increase of initial stiffness in the material, wood can contribute to further and the Standortagentur Tirol for the financial support
de monstrator, reduction of production avoidance of CO 2 emissions during use of the WoodCar project (project No. 861.421).
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