Design of a Multi-Material Body Structure with High Crashworthiness
1
Setup An experimental study was designed to compare the 3D fabric impact response against the usual woven fiberglass cloth within three different configurations including , 4 layer, 7 layer and 16 layer. Impact tests Were conducted using a Charpy Impact test Machine, fitted with a computer-controlled dynamic load cell , a LVDT and high speed camera. 0 1 2 3 4 5 6 7 8 9 10 16 Layer 7 Layer 4 Layer 3D Fabric Normalized Impact Energy Absorption (1/kg) Specimen with Different Configurations Energy Absorption for Different Specimens Results The composites containing the 3D fabric exhibited the highest energy absorption capacity. This is a crucial for enhancing the crashworthiness of structure. The impact shock is totally damped by crushing the vertical fibers of 3D fabric; thus, no dimple or damage becomes evident on the other side of the 3D composite (i.e., the passenger side). Impact test setup Charpy impact machine High speed camera DAQ No sign of damage on the passenger side! crushing of the vertical fibers totally damped The impact energy 3D Fabric after Impact Test 3D fabric filled with foam Experimental Study Enhanced Vehicle Crashworthiness with Innovative Multi-Material Body Structure Shahin Shadlou, Zohre Asaee & Farid Taheri Project Overview The National Highway Traffic Safety Administration’s primary mission is to “save lives, prevent injuries, and reduce economic costs due to road traffic crashes.” A lot of new technologies have been introduced to lower the number of collisions. Examples are the Electronic Stability Program (ESP), Collision Warning System, Anti- lock Breaking System (ABS), etc. Notwithstanding all efforts for inhibiting car crashes, the statistics reported by the Transport Canada indicate that the number of victims is still large, which implies that irrespective of new technologies, many fall victim to collisions. 0 5000 10000 15000 20000 25000 30000 1990 2009 Number of victims in car crashes serious Injuries Fatalities Therefore, enhancing vehicle crashworthiness is essential for protecting passengers’ lives while maintaining or even reducing the vehicle’s weight; thereby, improving the energy security and addressing the climate change by decreasing emissions of carbon dioxide (CO 2 ). The main Goals of this project are to introduce of an innovative multi-material configuration for vehicle body structure to: Increase the Crashworthiness & Reduce the Weight 3D Fabric What is the new material? The proposed material is a laminate of two or three thin magnesium sheets bonded with layers of 3D fabrics and conventional fiberglass. Why this combination? Each layer has its own unique properties which in a way contributes to the final desired mechanical response. Magnesium ALLOYS The lightest structural metallic alloys. High strength-to-weight ratio. Have been used in several components of modern cars. Fiber-glass Reinforced polymers Lightweight, excellent specific strength, and robust. More ductile and less expensive that carbon composites. Have been extensively used in various industries. Introduction 3D Fabric A recently developed fabric, consisting of two bi- directional woven fabrics, knitted together by vertical braided glass fiber pillars Outstanding impact resistance owing to the unique configuration Under an impact event, the vertical fibers gradually crash and damp a great amount of energy Vertical fibers . 3D Fabric Magnesium Magnesium Fiberglass Fiberglass Proposed Material Layup Computer simulations were performed, using the finite element method, to predict the impact response of specimens. By using computational simulations, configuration related parameters, such as the number and order of the layers thickness of the magnesium sheet, and 3D fabric, etc. could be optimized based on the desired properties; thus, saving experimental costs and time. Simulation of Impact Test Simulation The developed multi-material structure is able to bear a significant amount of impact energy-to-weight and is effectively capable of damping the impact energy and thus protecting passengers’ lives. Moreover, its light weight is in line with the energy saving and CO 2 reducing initiatives and policies. In the next step, we will optimize the configuration and address the issues related to mass production of this novel composite material. Conclusions & Future Work ACKNOWLEDGMENTS Financial support for this project was provided by AUTO21 and Meridian Lightweight Technologies.
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Transcript of Design of a Multi-Material Body Structure with High Crashworthiness
Setup
An experimental study was designed to compare the 3Dfabric impact response against the usual wovenfiberglass cloth within three different configurationsincluding , 4 layer, 7 layer and 16 layer.Impact tests Wereconducted using aCharpy Impact testMachine, fitted witha computer-controlleddynamic load cell , aLVDT and high speedcamera.
0
1
2
3
4
5
6
7
8
9
10
16 Layer 7 Layer 4 Layer 3D FabricNo
rmal
ized
Imp
act
Ene
rgy
Ab
sorp
tio
n (
1/k
g)
Specimen with Different Configurations
Energy Absorption for Different Specimens
Results
The composites containing the 3D fabric exhibited thehighest energy absorption capacity. This is a crucial forenhancing the crashworthiness of structure.
The impact shock is totally damped by crushing thevertical fibers of 3D fabric; thus, no dimple or damagebecomes evident on the other side of the 3D composite(i.e., the passenger side).
Impact test setup
Charpy impact machine
High speed camera
DAQ
No sign of
damage on the
passenger side!
crushing of the vertical
fibers totally damped
The impact energy
3D Fabric after Impact Test
3D fabric filled with
foam
Experimental Study
Enhanced Vehicle Crashworthinesswith Innovative Multi-Material Body Structure
Shahin Shadlou, Zohre Asaee & Farid Taheri
Project OverviewThe National Highway Traffic Safety Administration’sprimary mission is to “save lives, prevent injuries, andreduce economic costs due to road traffic crashes.” A lotof new technologies have been introduced to lower thenumber of collisions. Examples are the ElectronicStability Program (ESP), Collision Warning System, Anti-lock Breaking System (ABS), etc.
Notwithstanding all efforts for inhibiting car crashes,the statistics reported by the Transport Canada indicatethat the number of victims is still large, which impliesthat irrespective of new technologies, many fall victimto collisions.
0
5000
10000
15000
20000
25000
30000
1990 2009
Nu
mb
er
of
vic
tim
s in
ca
r
cra
she
s
serious Injuries Fatalities
Therefore, enhancing vehicle crashworthiness is essentialfor protecting passengers’ lives while maintaining or evenreducing the vehicle’s weight; thereby, improving theenergy security and addressing the climate change bydecreasing emissions of carbon dioxide (CO2).
The main Goals of this project are to introduce of aninnovative multi-material configuration for vehicle bodystructure to:
Increase the Crashworthiness
&Reduce the Weight
3D Fabric
What is the new material?
The proposed material is a laminate of two or three thinmagnesium sheets bonded with layers of 3D fabrics andconventional fiberglass.
Why this combination?
Each layer has its own uniqueproperties which in a waycontributes to the finaldesired mechanicalresponse.
Magnesium ALLOYS
The lightest structural metallic alloys. High strength-to-weight ratio. Have been used in several components of modern cars.
Fiber-glass Reinforced polymers
Lightweight, excellent specific strength, and robust. More ductile and less expensive that carbon
composites. Have been extensively used in various industries.
Introduction 3D Fabric
A recently developed fabric, consisting of two bi-directional woven fabrics, knitted together by verticalbraided glass fiber pillars
Outstanding impact resistance owing to the uniqueconfiguration
Under an impact event, the vertical fibers graduallycrash and damp a great amount of energy
Vertical fibers.
3D Fabric
Magnesium
Magnesium
Fiberglass
Fiberglass
Proposed
Material Layup
Computer simulations were performed,using the finite element method, to predictthe impact response of specimens.
By using computational simulations,configuration related parameters, such asthe number and order of the layersthickness of the magnesium sheet, and 3Dfabric, etc. could be optimized based onthe desired properties; thus, savingexperimental costs and time.
Simulation of Impact Test
SimulationThe developed multi-material structure is able to bear a significant amount ofimpact energy-to-weight and is effectively capable of damping the impactenergy and thus protecting passengers’ lives. Moreover, its light weight is inline with the energy saving and CO2 reducing initiatives and policies.
In the next step, we will optimize the configuration and address the issuesrelated to mass production of this novel composite material.
Conclusions & Future Work
ACKNOWLEDGMENTS
Financial support for this project was provided by AUTO21 and
Meridian Lightweight Technologies.
