Endnote X2 unknown error

This drove me crazy, I uninstalled and reinstalled word 2007 several times, still nothing new happened. Finally, I got the answer.  Here’s solution from Microsoft Help and Support website.

Original website link: http://support.microsoft.com/kb/921541

Delete the Word Data registry key

Most of the frequently used options in Word are stored in the Word Data registry key. A common troubleshooting step is to delete the Word Data registry key. The next time that you start Word, Word rebuilds the Word Data registry key by using the default settings.

To view these options in Word 2002 or Word 2003, click Options on the Tools menu.

To view these options in Word 2007, click the Microsoft Office Button, and then click Word Options.

Note When you delete the Word Data registry key, Word resets several options to their default settings. One such option is the “most recently used file” list on the File menu. Additionally, Word resets many settings that you customize in the Options dialog box.

To delete the Word Data registry key, follow these steps:

1. Exit all Office programs.
2. Click Start, click Run, type regedit, and then click OK.
3. Locate the following registry subkey, as appropriate for the version of Word that you are running:
   • Word 2002:
     HKEY_CURRENT_USER\Software\Microsoft \Office\10.0\Word\Data
   • Word 2003:
     HKEY_CURRENT_USER\Software\Microsoft\ Office\11.0\Word\Data
   • Word 2007:
     HKEY_CURRENT_USER\Software\Microsoft\ Office\12.0\Word\Data
4. Click Data, and then click Export on the File menu.
5. Name the file Wddata.reg, and then save the file to the desktop.
6. Click Delete on the Edit menu, and then click Yes.
7. Exit Registry Editor.
8. Start Word.

If Word starts and works correctly, you have resolved the problem. The problem was a damaged Word Data registry key. You may have to change several settings to restore your favorite options in Word.

If the problem is not resolved, restore the original Word Data registry key. Then, see the “Delete the Word Options registry key” topic.

To restore the original Word Data registry key, follow these steps:

1. Exit all Office programs.
2. Double-click the Wddata.reg icon on the desktop.
3. Click Yes, and then click OK.

Original Journey©2009

Maximum displacement in y direction is -0.3752×10e-4m and in x direction is 0.102×10e-4m.

Matlab Result (16 element)

Gauss Point maximum stress in X direction is 288.83Pa

Gauss Point minimum stress in X direction is -259.6Pa

Maximum stress in X direction is 335.77 Pa

Minimum stress in X direction is –245.89 Pa

Matlab Result (64 elements)

Maximum displacement in y direction is -0.4124×10-4m and in x direction is 0.1117×10-4m.

Matlab Result (64 elements)

Gauss Point maximum stress in X direction is 387.23Pa

Gauss Point minimum stress in X direction is -294.74Pa

Maximum stress in X direction is 430.85 Pa

Minimum stress in X direction is –298.61 Pa

ABAQUS RESULT (16 ELEMENTS)

X direction displacement (16 elements)

Y direction displacement (16 elements)

Stress in X direction

X direction stress at Gauss Point (16 elements)

ABAQUS RESULT (64 ELEMENTS)

X direction displacement (64 elements)

Y direction displacement (64 elements)

Stress in X direction (64 elements)

X direction Stress at Gauss Point (64 elements)

ABAQUS RESULTS (10,000 ELEMENTS)

X direction displacement (10,000 elements)

Y direction displacement

Discussion and Conclusion

Original Journey©2009

A cantilever beam is subjected to a uniform distributed load with value 30 N/m. The trapezoid beam has right vertical length 0.5m and left vertical length 1m. And top length is 2m.as shown in the graph.

B.C.: The vertical left side is fixed; the bottom and the vertical right side are free.

Material properties: isotropic material   E=3×10⁷Pa Poisson’s ratio ν=0.3

Regard this problem as a plane stress one. (beam width is 0.1m)

Math expression of the problem

PDE:

Boundary Conditions：

where

Weak form:

The integral over Ω in the weak form is computed as a sum of integrals over element domains Ωⁱ

Lⁱ is gather matrix which will gather the nodal displacements of each element from the global matrix.

w^’ is the portion of w corresponding to nodes that are not on an essential boundary, namely it is arbitrary except on an essential boundary condition.

Element Stiffness Matrix

Element external force matrix:

The weak form can then be written as

Using assembly operation, it can be written as:

Element type: 4 nodes bilinear quadrilateral element with two degrees of freedom in each node.

The element matrix will be integrated using 2×2 Gauss quadrature with the following coordinates in the parent element and weights:

The element stiffness matrix :

Continued……

Original Journey©2009

=====================================================================

$$ HM_OUTPUT_DECK created ****** by HyperMesh Version 9.0b122
$$ Ls-dyna Input Deck Generated by HyperMesh Version : 9.0b122
$$ Generated using HyperMesh-Ls-dyna 971 Template Version : 9.0-SA1-019
*KEYWORD
*TITLE
Carbon/Epoxy
*CONTROL_TERMINATION
$$ ENDTIM ENDCYC DTMIN ENDENG ENDMAS
5
*DATABASE_BINARY_D3PLOT
$$ DT/CYCL LCDT BEAM NPLTC
1.0000E-02
0
*NODE
1 1.0 1000.0 70.0
2 0.0 1000.0 70.0
………
6029 0.0 0.0 0.0
6030 1.0 0.0 0.0
*MAT_ORTHOTROPIC_ELASTIC
$HMNAME MATS 2facesheet
21.5800E-06 55.02 55.02 10.792 0.29 0.248 0.248
21.319 4.953 4.953

*MAT_CRUSHABLE_FOAM
$HMNAME MATS 1foam
11.0000E-07 0.111 0.1 2 4.5 0.4
*PART
$HMNAME COMPS 1foam
$HWCOLOR COMPS 1 27
1 1 1
$HMNAME COMPS 2facesheet_up
$HWCOLOR COMPS 2 4
2 1 2
$HMNAME COMPS 3facesheet_down
$HWCOLOR COMPS 3 6
3 1 2
*SECTION_SOLID
$HMNAME PROPS 1solid element
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*LOAD_SEGMENT_SET
$HMNAME LOADCOLS 4pressure
$HWCOLOR LOADCOLS 4 7
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*SET_SEGMENT
$HMNAME CSURFS 1load surface
$HWCOLOR CSURFS 1 4
1
1 402 3 2
1 2 3 402

206 199 200 205
205 200 201 204
204 201 202 203
*ELEMENT_SOLID
1 1 407 410 409 408 411 414 413 412
2 1 411 414 413 412 415 418 417 416
3 1 415 418 417 416 419 422 421 420
……
2800 3 5998 6026 6025 5997 6000 6028 6027 5999
2801 3 6000 6028 6027 5999 6002 6030 6029 6001
$$
$$ Sets Defined In HyperMesh
$$
*SET_NODE_LIST
$HMSET
$HMNAME SETS 1SPC1
1
1 2 3 4 5 6 7 8
……
385 386 387 388 389 390 391 392
393 394 395 396 397 398 399 400
401 402
*SET_NODE_LIST
$HMSET
$HMNAME SETS 2SPC2
2
4349 4350 4377 4378 4405 4406 4433 4434
4461 4462 4489 4490 4517 4518 4545 4546
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4685 4686 4713 4714 4741 4742 4769 4770
4797 4798 4825 4826 4853 4854 4881 4882
4909 4910
*SET_NODE_LIST
$HMSET
$HMNAME SETS 3SPC3
3
1549 1550 1577 1578 1605 1606 1633 1634
1661 1662 1689 1690 1717 1718 1745 1746
1773 1774 1801 1802 1829 1830 1857 1858
1885 1886 1913 1914 1941 1942 1969 1970
1997 1998 2025 2026 2053 2054 2081 2082
2109 2110
*SET_NODE_LIST
$HMSET
$HMNAME SETS 4SPC4
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419 420 423 424 427 428 431 432
435 436 439 440 443 444 447 448
451 452
*SET_NODE_LIST
$HMSET
$HMNAME SETS 5SPC5
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6011 6012 6013 6014 6015 6016 6017 6018
6019 6020 6021 6022 6023 6024 6025 6026
6027 6028 6029
*BOUNDARY_SPC_NODE
$HMNAME LOADCOLS 1SPC1
$HWCOLOR LOADCOLS 1 1
402 0 1
……
2 0 1
1 0 1
$HMNAME LOADCOLS 2SPC2
$HWCOLOR LOADCOLS 2 2
4910 0 1 1 1
……
1549 0 1 1 1
$HMNAME LOADCOLS 3SPC3
$HWCOLOR LOADCOLS 3 3
403 0 1
……
6029 0 1
*DEFINE_CURVE
$HMNAME CURVES 1pressure
$HWCOLOR CURVES 1 3
$HMCURVE 1 0 pressure
1 0 1.0 1.0 0.0 0.0 0
0.0 0.1
0.005 0.074
0.01 0.054
0.015 0.038
0.02 0.027
0.025 0.018
0.03 0.012
0.035 0.0074
0.04 0.004
0.045 0.0017
0.05 0.0
*DEFINE_CURVE
$HMNAME CURVES 2foam stain stress
$HWCOLOR CURVES 2 4
$HMCURVE 1 0 foam stain stress
2 0 1.0 1.0 0.0 0.0 0
0.0 0.0
0.05 0.00175
0.55 0.00175
0.7 0.0025
0.8 0.005
*END

============================================================

Original Journey©2009

The load is added on the whole surface of the top facesheet in these three design, this section provides the global and local response of the sandwich plate under blast loading.

Local and overall deformations

T=0.25 ms

T=0.5 ms

T=1 ms

T=2 ms

T=3 ms

T=4 ms

T=5 ms

Fig. 7 Global deform of the Carbon/epoxy Sandwich plate

Here’s Carbon/epoxy Sandwich plate vedio

T=0.25 ms

T=0.5 ms

T=1 ms

T=2 ms

T=3 ms

T=4 ms

T=5 ms

Fig. 8 Global deformation of steel sandwich plate

Here’s steel sandwich plate vedio

Energy absorption

The total energy of the sandwich plate is made of kinetic energy and internal energy. The latter is either dissipated by inelastic deformation and damage, or stored by the elastic material parts. The elastic strain energy is stored primarily in the top and bottom composite facesheets. Energy dissipation occurs in the crushable foam core.

Carbon/epoxy kinetic energy

Steel Kinetic Energy

Fig. 9. Distribution of kinetic energy

Fig.9 shows time history of the kinetic energy of the individual layer of the sandwich plate in design (1) and design (2). The kinetic energy is initially imparted to the top composite facesheet by the applied load. And then the induced compression wave propagates into the underlying materials, with particle velocity affected by the material properties. In design (1), the total kinetic energy is imparted to the top facesheet with the maximum value 55.266 J. In design (2), the kinetic energy is also imparted to the top facesheet, while it’s peak value is 12.443 J. Therefore, the implication is that with more stiffening facesheet, the kinetic energy will be reduced.

Carbon/epoxy internal energy

steel sandwich plate internal energy

Fig. 10.Distribution of the internal energy

Fig.10 shows the distribution of internal energy among the sandwich plate material parts. Elastic facesheets don’t play an important role on the internal energy, most of the strain energy of the sandwich plates is dissipated by permanent deformations of the foam core in both designs. In the desing(1), the energy dissipated by crushing of the foam core is 46.8 J, and in the design (2), the energy is 8.6 J.

Discussion and conclusions

The works show that the sandwich plate with steel facesheet design performs much better than the composite one under blast loads, both in the initial phase that is labeled by crushing of the foam core, and in the bending and stretching phase. This is because the stiffness increasing can prevent the foam core from excessive crushing, and also reduces overall deflection of the plate. Therefore, the total kinetic energy in design (2) is much lower than that in design (1). The kinetic energy has been reduced about 77.49﹪.

Similar reductions are found in the stored and dissipated internal energy and the plate deflection. The energy in the design (1) is only 19.15﹪, namely, the reduction is 80.85%. (See Fig. 11)

However, the material weight in design (1) is 36.6 g and the material weight in design (2) is 161g. Hereby, design one has a good performance on the material weight. (See Fig. 12)

kinetic energy&internal energy

Fig. 11 Kinetic Energy & Internal Energy

Weight Comparison

Fig. 12 Weight Comparison

In a nutshell, stiffness increasing in the facesheet will help sandwich plate has a superior performance. Steel material can not be widely used since weight is an issue. Therefore composites material like graphite/epoxy and glass fiber-epoxy which has stronger stiffness can be utilized. Also, we can rearrange the stack consequence of the composite materials to get higher overall stiffness. Further more, design layout can be rearranged to strength the facesheet, in other word, materials with stronger stiffness such as polyurea elastomers can be attached between the facesheet and foam core.

Original Journey ©2009

Introduction

A sandwich structured composite is a special class of composite materials that is fabricated by attaching two thin but stiff skins to a lightweight but thick core. The core material is normally low strength material, but its higher thickness provides the sandwich composite with high bending stiffness with overall low density.

Open and closed cell structured foam, balsa wood and syntactic foam, and composite honeycomb are commonly used core materials. Glass or carbon fiber reinforced laminates are widely used as skin materials. Sheet metal like steel is also used as skin materials in some cases.

Fig. 1 Sandwich Plate

Designs, material properties and loads

A multi-span sandwich plate supported by equally spaced rigid stiffeners is used. And it has assumptions as follows:

1. The connections between the different layers are perfect.
2. Assume moisture and temperature effects as zero.
3. Assume voids in the composite are zero.

The length of the plate is L=1000 mm. The length of a single span between supports is L^’= 600 mm. The total width, measured in the X₂-direction of Fig. 2 is assumed to be sufficiently large, so that the plate can be analyzed in plane strain, with displacements u₂ = 0 everywhere. Width of the supporting stiffeners is d = 100 mm, such that the clear span of the sandwich plate is L-d = 400 mm.

One structural arrangements of the plate is introduced, total thickness h = 70 mm, Fig. 2b. The laminated composite facesheets are bonded to a structural foam core, to form a symmetric sandwich cross-section. Each of the facesheets is h_f = 10 mm thick, while the foam core thickness is equal to h_c = 50 mm. Specific material properties of the facesheet laminates and foam core, listed in Tables 1, are derived from the following material models provided by the LS-Dyna finite element code (LSTC, 2003).

Fig. 2.a

Fig .2b Dimension of sandwich plate (Unit: mm)

Table 1.Elastic properties and dimensions of sandwich plate constituents

The facesheets are treated as homogeneous, orthotropic elastic material layers, and utilizes LS-Dyna Material Type 2. Besides, the facesheet in the 2^nd model is made of steel. Since it is isotropic elastic material, LS-Dyna Material Type 1 is chosen.

The structural foam core material (H100 Divinycell) is isotropic, closed cell foam. Under uniaxial compression, it deforms as shown Fig. 3 (Fleck, 2004). In the finite element calculations, the foam was modeled by LS-Dyna Material Type 63.

Fig. 3. Stress-strain behavior of H100 closed cell foam under compression.

Blast loads induce pressure p on the exposed structural surfaces. It will follow:

Blast loading curve

Finite element models

Fig. 5. Finite element model mesh

In the finite element mesh, solid elements of a constant width were utilized. The problem is treated as three-dimensional subjected to plane strain boundary conditions. In LS-Dyna, we use solid element with a width of 1.0 mm in the X₂-direction (Fig. 6).

Fig. 6.Finite element model mesh details (unit: mm)

The contact between the facesheet and foam are perfect bond, namely no opening happens between the layers.

（Continued……）

Original Journey ©2009

1. Load LS-DYNA user’s file and the template

2. Define the materials

3. Define the section(properties)

4. Define the part(component)

5. Create the load collector

6. Check the units(find it on a table)

7. Create the geometry of the model

· Create the node
· Create the line
· Create the surface
· Create the solid

8. Mesh the model(solid map)

· Refining topology to achieve a quality mesh
· Creating a Hex-Penta Mesh using Surfaces

9. Change the element type(*element_solid)

10. Clean the nodes

11. Create the set

12. Assign the boundary condition

13. Checking and Editing Mesh

14. Check the penetration

15. Checking the Minimum Time Step

16. Create set_segment

17. Define the curve(load)

18. Assign the load

19. Organize the component

20. Define Control Cards and Specify Output

21. Check list for your model

22. Output key file (or k file)

Original Journey ©2009

In the next few days, I will introduce how to use hypermesh as a pre-processor to establish a 3D model, and then use LS-DYNA as solver to simulate Strike, Shock and Blasting problems.

Original Journey © 2009