U.S. patent application number 12/312753 was filed with the patent office on 2011-03-03 for flange joint for structural member.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Tomohiro Numajiri.
Application Number | 20110047899 12/312753 |
Document ID | / |
Family ID | 41412312 |
Filed Date | 2011-03-03 |
United States Patent
Application |
20110047899 |
Kind Code |
A1 |
Numajiri; Tomohiro |
March 3, 2011 |
FLANGE JOINT FOR STRUCTURAL MEMBER
Abstract
A flange joint for structural members is provided, wherein by
avoiding stress concentration at a welded portion, the
cross-sectional size can be determined based on the base material
strength, and a structure can be reduced in weight and size. In a
flange joint for structural members, structural members are
connected to each other in a state where an end face, for example,
of an H-shaped steel beam is connected to a
structural-member-connecting face of an end plate by welding and a
non-connection face of the end plate is coupled to another
structural member. The structural-member-connecting face of the end
plate, to which the end face of the H-shaped steel beam is
connected, is provided with recessed grooves along the shape of the
welded portion of the end face.
Inventors: |
Numajiri; Tomohiro;
(Nagasaki, JP) |
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
41412312 |
Appl. No.: |
12/312753 |
Filed: |
June 11, 2008 |
PCT Filed: |
June 11, 2008 |
PCT NO: |
PCT/JP2008/060715 |
371 Date: |
May 26, 2009 |
Current U.S.
Class: |
52/173.1 ;
52/698 |
Current CPC
Class: |
E04B 2001/2442 20130101;
F05B 2230/30 20130101; B23K 2103/04 20180801; E04B 2001/2448
20130101; Y02E 10/728 20130101; E04B 2001/2457 20130101; B23K
2101/28 20180801; B23K 31/02 20130101; E04B 2001/2415 20130101;
F05B 2240/14 20130101; B23K 33/004 20130101; Y02E 10/72 20130101;
E04H 12/08 20130101 |
Class at
Publication: |
52/173.1 ;
52/698 |
International
Class: |
E04B 1/38 20060101
E04B001/38; E04H 12/00 20060101 E04H012/00 |
Claims
1. A flange joint for structural members, connecting structural
members to each other in a state where an end face of one
structural member is connected to one face of a plate-like member
by welding and the other face of the plate-like member is coupled
to the other structural member, wherein recessed grooves are
provided on the one face, to which the end face of the structural
member is connected, of the plate-like member along the shape of a
welded portion of the end face.
2. A flange joint for structural members, connecting structural
members to each other in a state where an end face of one
structural member is connected to one face of a plate-like member
by welding and the other face of the plate-like member is coupled
to the other structural member, wherein recessed grooves are
provided on the structural-member-connecting face of the plate-like
member, and the welded portion is positioned away from the T-shaped
base portion formed by the plate-like member and the structural
member.
3. A wind turbine generator system comprising a joint structure for
structural members according to claim 1.
4. A wind turbine generator system comprising a joint structure for
structural members according to claim 2.
Description
TECHNICAL FIELD
[0001] The present invention relates to a flange joint for
structural members, which connects (joins or couples) structural
members such as H-shaped steel beams or square steel tubes that
constitute, for example, a nacelle of a wind turbine generator
system.
BACKGROUND ART
[0002] Inside a nacelle of a wind turbine generator system, for
example, heavy components such as a drive train, including a
gearbox and a generator, and a control panel are installed. Such a
nacelle is provided with a cantilever structure in which structural
members, such as H-shaped steel beams, are flange-connected.
[0003] When structural members such as H-shaped steel beams are
flange-connected to each other, for example, as shown in FIGS. 5
and 6, a flange joint 10 in which plate-like members (end plates)
serving as flanges are attached to ends of the structural members
by welding is used. In this case, the plate-like members 12 that
are joined by butt welding to the ends of the H-shaped steel beams
(structural members) 11 serve as flanges, and bolts 14 are inserted
through a plurality of bolt holes 13 provided in both plate-like
members 12 and are tightly fastened by nuts for joining them. The
symbol "W" in the drawing indicates the welded portion.
[0004] In addition, known joint structures and joining processes
for joining a beam formed of a structural member, such as an
H-shaped steel beam, to a face of a column member include, for
example, those disclosed in Patent Documents 1 and 2.
[0005] Patent Document Japanese Unexamined Patent Application,
Publication No. 6-126444
[0006] Patent Document 2: Japanese Unexamined Patent Application,
Publication No. 7-292771
DISCLOSURE OF INVENTION
[0007] Recently, wind turbine generator systems have a tendency to
become larger with the increases in output. Accordingly, also in
order to reduce the loads on towers, foundations, and so on, it is
required to reduce the weight of nacelle baseplate structures.
[0008] However, the welded portion W where a plate-like member 12
is fixed to an end face of a structural member, such as an H-shaped
steel beam 11, is a portion where the cross-sectional shape of the
member is changed. Such a change in the cross-sectional shape leads
to the occurrence of stress concentration at the welded portion
W.
[0009] Therefore, in a structure in which stress concentration
occurs at the welded portion W, when the fatigue strength of a
member is considered, the cross-sectional size of the structural
member is determined depending on the cross-sectional shape of the
welded portion W. As a result, the cross-sectional size cannot be
determined on the basis of the strength of the structural member
(strength of the base material), such as the H-shaped steel beam
11, and a structure that is larger than the cross-sectional size
determined based on the base material strength is required.
Consequently, there is a problem in that not only does the weight
increase, but so does the space occupied by the steel beam.
[0010] The present invention has been accomplished under the
above-mentioned circumstances, and it is an object thereof to
provide a flange joint for structural members in which it is
possible to determine the cross-sectional size based on the base
material strength by avoiding stress concentration at the welded
portion and to realize reductions in the weight and size of a
structure.
[0011] The present invention employs the following solutions for
solving the above-mentioned problems.
[0012] A flange joint for structural members according to the
present invention is a flange joint for structural members in which
the structural members are connected to each other in a state where
an end face of one structural member is connected to one face of a
plate-like member by welding and the other face of the plate-like
member is coupled to the other structural member, wherein recessed
grooves are provided on the one face, to which the end face of the
one structural member is connected, of the plate-like member along
the shape of a welded portion of the end face.
[0013] In such a flange joint for structural members, since the
recessed grooves are provided on the one face of the plate-like
member, to which the end face of the one structural member is
connected, along the shape of the welded portion of the end face,
the position where the cross-sectional shape of the member is
changed and the position of the welded portion are displaced from
each other by the depth of the recessed grooves, and the fatigue
strength of the position where a cross-sectional shape of the
member is changed can be evaluated based on the base material
strength. The recessed grooves in this case desirably have
approximately U-shaped cross sections, because of their relative
ease of machining.
[0014] Another flange joint for structural members according to the
present invention is a flange joint for structural members in which
the structural members are connected to each other in a state where
an end face of one structural member is connected to one face of a
plate-like member by welding, and the other face of the plate-like
member is coupled to the other structural member, wherein recessed
grooves are provided on the structural-member-connecting face of
the plate-like member, and the welded portion is positioned away
from the T-shaped base portion formed by the plate-like member and
the structural member.
[0015] In such a flange joint for structural members, since the
welded portion is positioned away from the T-shaped base portion
formed by the plate-like member and the structural member by
forming the recessed grooves on the structural-member-connecting
face of the plate-like member, the fatigue strength of the T-shaped
base portion can be evaluated based on the base material strength.
The recessed grooves in this case desirably have approximately
U-shaped cross sections, because of their relative ease of
machining.
[0016] A wind turbine generator system according to the present
invention is characterized by including a joint structure for
structural members according to Claim 1 or 2.
[0017] Since such a wind turbine generator system has the joint
structure that enables evaluation of the fatigue strength of the
position where the cross-sectional shape of the member is changed
based on the base material strength, a structure, such as the
nacelle baseplate, can be reduced in size and weight.
[0018] Accordingly, in the flange joint for structural members
according to the present invention and the wind power generator
including the same, by shifting the position where stress is
concentrated from the welded portion, the cross-sectional size of
the structural member can be determined based on the strength of
the base material when the fatigue strength of the member is
considered. That is, the cross-sectional size of a structure
employing the flange joint of the present invention can be
determined using the base material strength of the structural
member constituted by, for example, an H-shaped steel beam.
Accordingly, a structural member having a cross-sectional size
smaller than that of a conventional structure, which is calculated
from the strength of the welded portion, can be employed.
[0019] In other words, the flange joint of the present invention
enables determination of the cross-sectional size based on the base
material strength by avoiding stress concentration at the welded
portion, and thereby reductions in weight and size of a structure
can be realized.
[0020] This results in reductions in the weight of the structure
and in the space occupied by the structural member, compared with
conventional ones. Consequently, reductions in the weight and the
size of a structure (for example, the nacelle baseplate of a wind
turbine generator system) are possible. Furthermore, in addition to
avoidance of stress concentration at the welded portion, it is
possible to avoid spreading of welding distortion to the coupling
faces. This has a significant benefit in terms of improved
reliability of the product (for example, a wind turbine generator
system).
BRIEF DESCRIPTION OF DRAWINGS
[0021] FIG. 1 is an exploded perspective view of a flange joint for
structural members according to an Embodiment of the present
invention, showing a state before welding.
[0022] FIG. 2 is a longitudinal sectional view of the essential
parts of the flange joint for structural members shown in FIG. 1,
showing a state after welding.
[0023] FIG. 3 is a side view showing a wind turbine generator
system including the flange joint according to an Embodiment of the
present invention.
[0024] FIG. 4 is a diagram showing an exemplary structure of the
inside of a nacelle of the wind turbine generator system shown in
FIG. 3.
[0025] FIG. 5 is a diagram showing a conventional example of a
flange joint for structural members.
[0026] FIG. 6 is a longitudinal sectional view showing the
essential parts of a welded portion of the conventional example
shown in FIG. 5.
EXPLANATION OF REFERENCE SIGNS
[0027] 1: wind turbine generator system [0028] 3: nacelle [0029]
20: flange joint [0030] 21: H-shaped steel beam (structural member)
[0031] 22: end plate (plate-like member) [0032] 23: recessed groove
[0033] 24: T-shaped base portion [0034] 30: nacelle baseplate
[0035] 34: nacelle baseplate body [0036] 35: structural member
[0037] W: welded portion
BEST MODE FOR CARRYING OUT THE INVENTION
[0038] An Embodiment of the flange joint for structural members
(hereinafter, referred to as "flange joint") according to the
present invention will now be described with reference to FIGS. 1
to 4.
[0039] FIG. 3 is a side view showing a wind turbine generator
system including the flange joint according to this Embodiment.
[0040] The wind turbine generator system 1 shown in FIG. 3 includes
a tower 2 vertically installed on a foundation B, nacelle 3 mounted
atop the tower 2, and a rotor head 4 provided on the nacelle 3 so
as to be rotatable around an approximately horizontal axis.
[0041] The rotor head 4 is fitted with a plurality of (for example,
three) wind turbine rotor blades 5 that are arranged radially
around the rotation axis thereof. By doing so, the force of wind
blowing against the wind turbine rotor blades 5 from the direction
of the rotation axis of the rotor head 4 is converted into motive
energy causing the rotor head 4 to rotate around the rotation
axis.
[0042] For example, as shown in FIG. 4, the nacelle 3 includes a
nacelle baseplate 30 mounted atop the tower 2 and a cover (not
shown) covering the nacelle baseplate 30 from the top. In the
exemplary structure shown in the drawing, on the nacelle baseplate
30, heavy components (equipment) such as a gearbox 31, a generator
32, and a control panel 33 are provided.
[0043] The rotation of the rotor head 4, after being stepped up via
the gearbox 31, drives the generator 32, resulting in generation of
electricity.
[0044] Incidentally, the above-described nacelle 3 whose nacelle
baseplate 30 is rotatably supported on the top end of the tower 2
can change the direction thereof according to the wind direction.
This nacelle baseplate 30 includes a structural member 35, such as
an H-shaped steel beam, extending from the nacelle baseplate body
34 that rotates on the tower 2 toward the opposite side with
respect to the rotor head 4.
[0045] This structural member 35 is connected to the nacelle
baseplate body 34 via a flange joint 20, resulting in a cantilever
structure.
[0046] The above-described flange joint 20 for structural members
will be described with reference to FIGS. 1 and 2 below. In
addition, the flange joint 20 shown in the drawings is a case
employing an H-shaped steel beam 21 as the structural member
35.
[0047] In the flange joint 20, an end face 21a of the H-shaped
steel beam (structural member) 21 is connected to the
structural-member-connecting face (one face) 22a of an end plate
(plate-like member) 22 by welding, a non-connection face (the other
face) 22b of the end plate 22 is coupled to the non-connection face
of another structural member, and, in this state, the structural
members are connected to each other by a plurality of bolts (not
shown) passing through bolt holes 25. In addition, the structural
members 35 that are connected to each other are not limited to the
same types of members, for example, the H-shaped steel beams
21.
[0048] The structural-member-connecting face 22a of the end plate
22 to which the end face 21a of the H-shaped steel beam 21 is
connected is provided with recessed grooves 23 along the shape of
the welded portion of the end face 21a. These recessed grooves 23
desirably have approximately U-shaped cross sections, because of
their relative ease of machining.
[0049] In the exemplary structure shown in the drawings, employing
the H-shaped steel beam 21 as the structural member, the recessed
grooves 23 provided on both sides of a flange portion 21b are
indispensable. However, at both sides of a web portion 21c, the
strength required is small compared to that of the above-described
flange portion 21b, and therefore formation of the recessed groove
23 is optional there.
[0050] That is, by forming the recessed grooves 23, the
structural-member-connecting face 22a of the end plate 22 is
provided with a welding face Wf having approximately the same shape
(rectangle) as that of the cross-sectional shape of the flange
portion 21b. The welding face Wf at a position higher than a
T-shaped base portion 24 by the depth of the recessed groove 23 and
the end 21a of the flange portion 21b are coupled and welded to
each other. On the other hand, the end 21a of the web portion 21c
is coupled and welded to a welding face Wf', which is shown by the
broken line in the drawing, of the structural-member-connecting
face 22a, because no recessed groove 23 is provided. However, a
welding face Wf like that in the flange portion 21b may be formed,
and the coupling and welding may be performed.
[0051] In other words, in the above-described flange joint 20, the
structural members are connected to each other in a state where the
end face 21a of the H-shaped steel beam 21 is connected to the
structural-member-connecting face 22a of the end plate 22 by
welding and where the non-connection face 22b of the end plate 22
is coupled to another structural member, and by providing the
recessed grooves 23 on the structural-member-connecting face 22a of
the end plate 22, the position of the welded portion W is located
away from the T-shaped base portion 24 formed by the end plate 22
and the H-shaped steel beam 21 by a distance that is approximately
equivalent to the depth of the recessed groove 23.
[0052] According to such a flange joint 20, the position where the
cross-sectional shape of the H-shaped steel beam 21 is changed and
the position of the welded portion W are shifted from each other by
the depth of the recessed groove 23, and thereby the fatigue
strength at the position where the cross-sectional shape of the
H-shaped steel beam 21 is changed can be evaluated based on the
base material strength of the end plate 22. That is, in the
above-described flange joint 20, the recessed grooves 23 are
provided on the structural-member-connecting face 22a of the end
plate 22, which allows the position of the welded portion W to be
located away from the T-shaped base portion 24. Therefore, the
fatigue strength of the T-shaped base portion 24, which is the
position where the cross-sectional shape of the H-shaped steel beam
21 is changed, can be evaluated based on the base material strength
of the end plate 22 where the T-shaped base portion 24 is
provided.
[0053] Therefore, in the above-described flange joint 20, by
shifting the position (T-shaped base portion 24) where stress is
concentrated from the position of the welded portion W, when the
fatigue strength of the structural member 35 such as the H-shaped
steel beam 21 or the end plate 22 is considered, the
cross-sectional size of the structural member 35 can be determined
based on the strength of the base material. That is, the
cross-sectional size of a structure, such as the nacelle base plate
30, employing the flange joint 20 of the present invention can be
determined using the base material strength of the structural
member 35 constituted by, for example, the H-shaped steel beam 21
and the end plate 22. Accordingly, a structural member 35 having a
cross-sectional size smaller than that of a conventional structure,
which is calculated from the strength of the welded portion W, can
be employed
[0054] Thus, by providing the recessed grooves 23 on the
structural-member-connecting face 22a of the end plate 22 for
providing the welded portion W at a position away from the end
plate 22 and the T-shaped base portion 24 of the flange joint 20,
the fatigue evaluation of the T-shaped base portion 24 can be
performed with the base material strength of the end plate 22, and
the welded portion W can be evaluated as a welded structure in
which a plate and a plate are coupled and welded to each other.
[0055] In general, when the amount of weld penetration of the
welded portion W in general rolled steel is in the same range, even
if the same raw material is used, the fatigue strength varies
depending on whether the pattern (including weld leg length) of the
welded structure is a T-shaped or flat coupling, and the fatigue
strength of a flat coupling structure is larger than that of a
T-shape one.
[0056] That is, in the flange joint 20 of the present invention,
stress concentration at the welded portion W is avoided to allow
the cross-sectional size to be determined based on the base
material strength, resulting in reductions in weight and size of a
structure having the flange joint 20.
[0057] This can decrease the weight of the structure and the space
occupied by the structural member, and thereby the structure, such
as the nacelle baseplate 30 of the wind turbine generator system 1,
can be reduced in weight and size.
[0058] Furthermore, in the above-described flange joint 20, stress
concentration at the welded portion W can be avoided, and also
welding distortion can be prevented from spreading to the
structural-member-connecting face 22a, which becomes a connection
face, and the non-connection face 22b of the end plate 22.
Consequently, for example, product reliability of the wind turbine
generator system 1 and other apparatuses can be improved.
[0059] Incidentally, in the above-described Embodiment, application
of the flange joint 20 of the present invention to a nacelle
baseplate 30 of a wind turbine generator system 1 is described, but
the application is not limited thereto, and various types of
application are possible. In addition, the structural member 35
that is welded to the end plate 22 is not limited to the
above-described H-shaped steel beam 21, and it is understood that
application to other structural members such as channel steel
members and angled steel members is possible.
[0060] Furthermore, the present invention is not limited to the
above-described Embodiment and can be appropriately modified
without departing from the gist of the present invention.
* * * * *