material parameter identification of concrete by an impact (combination of radioss & hyperstudy)
DESCRIPTION
The development of modern electric power tools for professional applications requires special attention to be simultaneously paid to the two main groups of characteristics: those which take into consideration the efficiency and user comfort of the tool, and those which determine the robustness and durability of the devices. For the fulfillment of these two groups of attributes, computer-aided simulations using the finite element software Radioss® in combination with HyperStudy® and has become central to the development process of Stanley Black & Decker Deutschland GmbH. The computer aided simulations are used throughout the development cycle - from the pre-development phase, right up to testing near-series prototypes and beyond to improving design based upon product-failure returns. From the point of view of the performance and durability of our machines, it is our goal to design products to ever higher standards. To achieve and surpass the exacting requirements of our professional customers, one key factor is to increase the performance of the machines. There are many factors which together contribute to achieve the best performance of the impact parts. To optimize the performance it is necessary to understand first, how is the material behavior during an impact like concrete. A verification of test and simulation will be achieved by the material parameter identification with Radioss® in combination with HyperStudy®. This combination helps Stanley Black & Decker Deutschland GmbH to develop more powerful professional tools.TRANSCRIPT
1
Material parameter identification of concrete by an impact
(Combination of Radioss & HyperStudy)
by
Vitali Almendinger
2
Agenda
• Company/ Product introduction
• Hammer description
• Measurement/ Simulation principle
• Mesh Size/ Properties
• DOE
• Definition of design variables/ Specifications
• Definition of the responses: characteristic measures of test curve
• DOE results
• Optimization and results
3
Company/ Product introduction
Today DEWALT is a leading brand of professional power tools in the world and
in the last 5 years the fastest growing power tool brand in the world.
Compact Hammers Mid Size Hammers Demolition Hammers
4
Hammer description
5
Initial Velocity
Gravity
Measurement Points
Measurement/ Simulation principle
BCS mid Nodes
DOF (0,0,1)
Equivalent
Nodes
BCS Block
DOF (0,0,0)
Ram
Drill
Concrete
Core
Concrete
Block
/MAT/LAW1
/MAT/LAW24
6
Measurement/ Simulation principle V
elo
cit
y o
f R
am
[m
/s]
Velo
cit
y o
f D
rill [
m/s
]
Time [ms]
Time [ms]
7
Measurement/ Simulation principle
Statistical
Reference
Curve Measurement
Curves
8
Mesh Size/ Properties
9
Mesh Size/ Properties
Mesh parameters
• Concrete parts only HEX-Mesh
• Concrete Core constant Mesh size of ̴ 0.3 mm
Properties
• Steel parts Isolid=24
(with Isolid=1, to much Hourglassenergy)
• Concrete parts must have Isolid=1
(with Isolid=24, to much damping)
10
Definition of design variables/ Specifications
7 Design variables
• fc (Concrete uniaxial compression strength)
• ft/fc (Concrete tensile strength ratio)
• ν (Poisson’s ratio)
• Ht (Concrete data tensile tangent modulus)
• ky (Concrete plasticity initial value of
hardening parameter)
• Stfac Type20 Ram and Tool (Interface
stiffness scale factor)
• Stfac Type20 Tool Tip and Concrete Core
(Interface stiffness scale factor)
DOE Specifications
• Hammersley
• Number of runs: choose by default (36 runs)
11
Definition of the responses: characteristic
measures of test curve
11
Max. D
ista
nce
Curvature Length
Pen
e_m
ax
Slope
Response
• Maximum Penetration
• Curvature Length (at a node displacement of 0.15mm)
• Slope
• Max. Distance (of the time axis 6e-4s until 9e-4s)
• Ram velocity at the end
12
DOE Results
12
Max. D
ista
nce
Curvature Length
Pen
e_m
ax
Slope
Curvature
Length
Slope
Max.
Distance
Ram V_end
Pene_Max C
urv
atu
re
Len
gth
Stf
ac
_R
am
_To
ol
Ma
x.
Dis
tan
ce
Ram
V_
en
d
Pe
ne_
Ma
x
Ht
f c
Stf
ac
_T
ip_
Co
re
f t/f
c
ky
Po
iss
on
’s
rati
o
Slo
pe
13
DOE Results /
Optimization
13
Optimization
Design variables
• fc (Concrete uniaxial compression strength)
• ft/fc (Concrete tensile strength ratio)
•Stfac Type20 Ram and Tool (Interface stiffness scale factor)
• Stfac Type20 Tool Tip and Concrete Core (Interface stiffness scale factor)
Optimization Specification
• Genetic Algorithm
Statistical
Reference
Curve Start Values For
Optimization
DOE Result
Curves
14
Optimization Result
15
Thanks for Your Attention!