Netherlands-Based Firm Depends Upon
Nonlinear Capabilities to Ensure Ride Safety
CASE STUDY
IV-INFRA
EXECUTIVE SUMMARY
- Successful at solving nonlinear problems
- ANSYS Parametric Design Language (AP
- Allows EnventureGT to react quickly to u
Introduction
Challenge
Ride safety is a constant concern for amuse-
The much-publicized 1,800-ton structure now
ment park owners and visitors. With more than
stands proud on the River Thames, just oppo-
309 million thrill-seekers passing through park
site the Houses of Parliament. The wheel is
gates annually, the slightest mechanical error
capable of carrying up to 4,500 riders a day,
can be disastrous. Fortunately, many ride
enabling them to see up to 25 miles across the
developers do their part to avoid such situations
city. But perhaps the most remarkable of all the
by employing skilled engineers to design and
statistics is that the main contractor had just 16
analyze each part prior to construction.
months to complete the project from start to
finish.
Challenge:
One example of rigorous engineering is the
Design and construct the world’s
British Airways London Eye. Standing at more
Designed and developed by Marks Barfield
largest observation wheel in just
than 135 m and 120-ft taller than Big Ben, the
Architects, the future of the wheel lay in the
16 months
London Eye is the world’s largest observation
hands of the Dutch steel fabrication and con-
wheel – a far cry from the original 250-ft. Ferris
struction company Hollandia b.v. In order to
wheel invented by George Ferris Jr.
complete the project on time, Hollandia
Solution:
employed
Use ANSYS® Multiphysics for its
(Papendrecht, The Netherlands) as a subcon-
strong nonlinear capabilities
tractor for the design calculations and verifica-
the
services
of
Iv-Infra
tions of the steel structure.
The first step: a feasibility study and prelimi-
Benefits:
nary calculations so that the factory could
begin constructing parts for the assembly of
parts
the landmark structure. The two-month feasi-
Offers strong contact solvers
for gap and spring models
Images courtesy of Iv-Infra
Ability to easily verify the local
bility study investigated five main issues that
would determine how the final structure would
be designed:
Overall stability
Fatigue loading
How the components would stand up to
Iv-Infra depended upon ANSYS’ nonlinear capabilities to
analyze gap and spring models.
different types of loads
“We decided to use ANSYS, which made the creation of the model relatively easy, but it also allowed us to verify the individual parts. The
www.ansys.com
majority of the model is nonlinear, and ANSYS is recognized for its
strengths in this area.”
CASE STUDY
Dynamic behavior due to wind conditions
easy, but also allowed us to verify the indi-
the size and placement of the dampers and
Static strength of the steel
vidual parts. The majority of the model is
the behavior of the structure.
nonlinear, and ANSYS is recognized for its
Benefits
strengths in this area.”
“As well as being suitable for constructing a
Once the model was built, parameters were
model of the entire structure, ANSYS also
added to determine the fatigue life of the
made verifying the local parts easier and
structure. The movement of the rim made this
offers strong contact solvers for the gap and
very difficult, and imperfections had to be
spring models,” Lanser continued. “Our
built into every position of the wheel. To
choice of this analysis tool was also guided
work out the fatigue, consultants plotted the
by the fact that all analyses were nonlinear
stress against the number of cycles. Given
and that the English verification body that
that the wheel turns two times an hour, that's
was approving our calculation were ANSYS
a massive 438,000 cycles in the planned 50-
users.
year time scale.
Detail of spoke cable connector
“All participants are delighted that the
Another major factor in the analysis of the
London Eye is fully operational. The London
Solution
London Eye was the dynamic behavior of the
Eye is already being hailed as a monument
Due to time restrictions, many calculations
structure due to wind loading. Hollandia also
for future generations – not bad considering
were worked out up-front for the feasibility
wanted to ensure the ride was as comfortable
the deadline the whole team had to meet.”
test, and then later ratified using finite element
as possible for the visitors, with motion sick-
analysis (FEA) techniques to ensure accuracy.
ness being a real concern. The company
Once the feasibility study determined that the
decided to use tuned mass dampers in the rim
project could be completed successfully, the
near each capsule.
team began building a complete model of the
structure in ANSYS Multiphysics, distributed
“Using the ANSYS Multiphysics, we per-
by ANSYS Inc. (Canonsburg, Pa., U.S.A.).
formed dynamic wind analyses on every one
The model was complicated because it was
of the 32 capsules, according to the advice of
made from many different elements and
the
designed to be in constant motion.
Holland,” said Lanser. “The calculation was
TNO-Bouw
research
institute
in
enormous because the load on each capsule is
“Because of the complexity of the model we
different during the course of the cycle, so we
were dealing with,” said Iv-Infra’s Arie
had to investigate 6,400 loadings on each one
Lanser, “we decided to use ANSYS, which
over a period of 320 seconds. But that pro-
made the creation of the model relatively
vided us with the data required to determine
www.ansys.com
ANSYS Inc.
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Mesh of the London Eye
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