Abstract:
The conventional technologies are impractical for the following reason. CAD has been the only solution for changing an analysis model with adding or deleting a fillet. In this case, it is necessary to repeat the mesh generation and condition configuration, which makes the work time longer especially for large-scale or complicated shape data. The present invention, accomplished to solve the above-mentioned problem, provides an analysis mesh generation apparatus including a computer for generating a mesh model. The apparatus is configured to create a screen for selecting an edge of a mesh model and entering a radius of a fillet to be applied to the selected edge; and to create a screen for generating a mesh for the applied fillet, generating a new mesh model by deleting or adding an area enclosed by a contour of the mesh model and the fillet, and displaying the new mesh model.

Description:
CLAIM OF PRIORITY 
       [0001]    The present application claims priority from Japanese Patent Application JP 2008-295042 filed on Nov. 19, 2008, the content of which is hereby incorporated by reference into this application. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a CAE (Computer Aided Engineering) system that numerically simulates physical phenomena based on numerical analysis using a computer. More particularly, the invention relates to generation of analysis models in CAE. 
       BACKGROUND OF THE INVENTION 
       [0003]    Using the CAE in product development processes reduces development costs and shortens a design and development period. In the CAE, an analysis model is generated from a shape model generated by a CAD (Computer Aided Design) system and is used, for example, for intensity analysis, thermal analysis, or vibration analysis based on analysis methods, such as the finite element method or the boundary element method. The analysis model generation in the CAE requires a large quantity of work such as generation of a mesh model from the shape model and configuration of parameters or boundary conditions for each element of the mesh model. 
         [0004]    To reduce the workload for analysis model generation, some technologies have been proposed. For example, Japanese Unexamined Patent Application Publication No. HEI3-70083 discloses a technology of integrating the functions of shape model generation, analysis mesh generation, and model analysis into a single system. Methods of generating a fillet as a function of shape model generation are disclosed in Japanese Unexamined Patent Application Publication Nos. HEI8-137917 and HEI8-153125, and in a book entitled 3D CAD—Basics and Applications, pp. 143-150 (KYORITSU SHUPPAN CO., LTD, 1991). 
         [0005]    Japanese Unexamined Patent Application Publication No. 2006-301753 discloses a technology of generating an intended analysis model using an existing analysis model. The technology recognizes geometrical characteristics of the existing analysis model from the element faces of the exterior surface of the model. The technology provides the geometrical characteristics or the relation between the geometrical characteristics with a dimensional value (dimensional constraint) of a transformed shape. The technology transforms the mesh using the geometrical characteristics and the dimensional constraint as restrictions to generate an intended analysis model. The technology is capable of adding or deleting the shape characteristics, such as ribs and holes. 
         [0006]    Similarly to Japanese Unexamined Patent Application Publication No. 2006-301753, Japanese Unexamined Patent Application Publication No. 2003-108609 discloses a technology of generating an intended analysis model using an existing analysis model. The technology provides the existing analysis model with corresponding reference points. The technology moves the reference points based on the correlation of the reference points and the mesh data in the existing analysis model. In this manner, the technology transforms the mesh data in the existing analysis model to generate the intended analysis model. 
         [0007]    Technologies capable of generating an analysis model from a CAD model that is generated during a design process are disclosed in Japanese Unexamined Patent Application Publication Nos. HEI3-70083, HEI8-137917, and HEI8-153125, and in the book entitled 3D CAD—Basics and Applications. Even when a shape is changed due to a design change or a product model change, the technologies can apply necessary modifications to the CAD model and generate an analysis model from the CAD model. 
         [0008]    Technologies capable of changing shapes of an existing analysis model and generating a newly shaped analysis model are disclosed in Japanese Unexamined Patent Application Publication Nos. 2006-301753 and 2003-108609, and in CDAJ NEWS vol. 51, March 2008. The technologies eliminate processes of the generation of meshes and the configuration of conditions for a reshaped CAD model, greatly reducing the workload for analysis model generation. 
         [0009]    As mentioned above, CAE is accompanied by the problem of reducing the workload for analysis model generation. To solve this problem, the technology disclosed in Japanese Unexamined Patent Application Publication No. HEI3-70083 can reduce the workload for analysis model generation by integrating the functions of shape model generation, analysis mesh generation, and model analysis into a single system. The technologies disclosed in Japanese Unexamined Patent Application Publication Nos. HEI8-137917 and HEI8-153125, and in the book entitled 3D CAD—Basics and Applications can generate a fillet for the CAD model and generate an analysis model after an additional fillet is generated. 
         [0010]    However, these technologies need to reconfigure the mesh generation work and the conditioning work each time the CAD is used to change shapes. Therefore, the technologies are impractical for large-scale and complicated shape data. 
         [0011]    The technologies disclosed in Japanese Unexamined Patent Application Publication Nos. 2006-301753 and 2003-108609, and in CDAJ NEWS vol. 51 seem to be more effective for the problem because the technologies generate an intended analysis model using an existing analysis model. The technologies use the existing analysis model to generate an intended analysis model, eliminating processes of the generation of mesh data and the configuration of boundary conditions. Accordingly, the technologies can greatly reduce the workload for the analysis model generation. The technology disclosed in Japanese 
         [0012]    Unexamined Patent Application Publication No. 2006-301753 is capable of changing dimension, such as a distance between plane faces of the mesh model or a radius of a cylinder model. However, the technology is incapable of adding or deleting a fillet. The technology disclosed in Japanese Unexamined Patent Application Publication No. 2003-108609, which reshapes the analysis model only by moving nodes, is incapable of adding or deleting a fillet. The technology disclosed in CDAJ NEWS vol. 51 can change a fillet radius by moving mesh nodes of a selected fillet. 
         [0013]    Therefore, the conventional technologies are impractical for the following reason. CAD has been the only solution for changing an analysis model with adding or deleting a fillet. In this case, it is necessary to repeat the mesh generation and condition configuration, which makes the work time longer especially for large-scale or complicated shape data. 
         [0014]    The object of the present invention is to provide an analysis mesh generation apparatus that can directly delete or add a fillet for an analysis model. 
       SUMMARY OF THE INVENTION 
       [0015]    The present invention, accomplished to solve the above-mentioned problem, provides an analysis mesh generation apparatus including a computer for generating a mesh model. The apparatus is configured to create a screen for selecting an edge of a mesh model and entering a radius of a fillet to be applied to the selected edge; and to create a screen for generating a mesh for the applied fillet, generating a new mesh model by deleting or adding an area enclosed by a contour of the mesh model and the fillet, and displaying the new mesh model 
         [0016]    The present invention also provides an analysis mesh generation apparatus including a computer for generating a mesh model. The apparatus is configured to create a screen for specifying a mesh model; to create a screen for selecting an edge for a fillet to be applied in the specified mesh model; to create a screen for entering a radius of the fillet; and to create a screen for generating a fillet face based on the radius of the fillet, generating a fillet area shape from the fillet face and a face generated by extending an element face adjacent to the edge, generating a new mesh model by deleting or adding a mesh for an area enclosed by the fillet area shape on a contour of the mesh model, and displaying the new mesh model. 
         [0017]    Preferably, if the edge is convex, the new mesh model is generated by deleting the mesh for the area enclosed by the contour of the mesh model and the fillet area shape. 
         [0018]    Preferably, if the edge is concave, the new mesh model is generated by adding the mesh for the area enclosed by the contour of the mesh model and the fillet area shape. 
         [0019]    Preferably, the apparatus is configured to further create a screen for specifying a division count for dividing the fillet face in a circumferential direction of the fillet; and to create a screen for displaying the new mesh model that is obtained by dividing the fillet face in the fillet area shape by the division count. 
         [0020]    Preferably, the apparatus is configured to further create a screen for specifying a threshold value for an edge extraction angle between normal lines of adjacent meshes; to create a screen for extracting an edge group that has the edge extraction angle greater than or equal to the threshold value, and displaying the new mesh model that is obtained by adding the extracted edge group to the mesh model; and to create a screen for selecting the edge group that is added to the mesh model. 
         [0021]    Preferably, the apparatus is configured to further create a screen for recognizing characteristics of the mesh model for edge extraction; to create a screen for displaying the new mesh model that is obtained by adding a boundary between the characteristics to the mesh model which the characteristics is recognized of; and to create a screen for selecting the boundary between the characteristics in the new mesh model. 
         [0022]    The present invention also provides an analysis mesh generation apparatus including a computer for generating a mesh model. The apparatus is configured to create a screen for specifying a mesh model; to create a screen for selecting a fillet face to be deleted from the mesh model; and to create a screen for generating a fillet area shape from the fillet face and a face generated by extending an element face adjacent to the fillet face, generating a new mesh model by deleting or adding a mesh for an area enclosed by the fillet area shape on a contour of the mesh model, and displaying the new mesh model. 
         [0023]    Preferably, if the fillet face is convex, the new mesh model is generated by adding the mesh for the area enclosed by the contour of the mesh model and the fillet area shape. 
         [0024]    Preferably, if the fillet face is concave, the new mesh model is generated by deleting the mesh for the area enclosed by the contour of the mesh model and the fillet area shape. 
         [0025]    Preferably, the apparatus is configured to further create a screen for recognizing characteristics of the mesh model for edge extraction; to create a screen for displaying the new mesh model that is obtained by adding a boundary between the characteristics to the mesh model which the characteristics is recognized of; and to create a screen for selecting and deleting the boundary between the characteristics in the new mesh model. 
         [0026]    An analysis mesh generation apparatus according to the present invention, in which a fillet is directly deleted or added for the analysis mesh model, can reduce the number of processes for analysis model generation and the hours of work 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1  shows a block diagram of an analysis mesh generation apparatus in accordance with a first embodiment of the present invention; 
           [0028]      FIG. 2  shows an example of a screen of a targeted analysis mesh specification section; 
           [0029]      FIG. 3  shows an example of a screen of a fillet information input section during fillet addition; 
           [0030]      FIG. 4  shows an example of a screen of the fillet information input section during fillet deletion; 
           [0031]      FIG. 5  shows examples of PAD for processes of a fillet area shape generation section; 
           [0032]      FIG. 6  shows an example of a process of the fillet area shape generation section during fillet addition; 
           [0033]      FIG. 7  shows an example of a process of the fillet area shape generation section during fillet deletion; 
           [0034]      FIGS. 8 and 9  show examples of PADs for processes of a fillet mesh addition/deletion section; 
           [0035]      FIG. 10  shows an example of a process of the fillet mesh addition/deletion section when a fillet is added to a convex edge; 
           [0036]      FIG. 11  shows an example of a process of the fillet mesh addition/deletion section when a fillet is added to a concave edge; 
           [0037]      FIG. 12  shows an example of a process of the fillet mesh addition/deletion section when a convex fillet is deleted; 
           [0038]      FIG. 13  shows an example of a process of the fillet mesh addition/deletion section when a concave fillet is deleted; 
           [0039]      FIG. 14  shows the first example of usage procedure for the analysis mesh generation apparatus of the present invention; 
           [0040]      FIG. 15  shows the second example of usage procedure for the analysis mesh generation apparatus of the present invention; 
           [0041]      FIG. 16  shows the third example of usage procedure for the analysis mesh generation apparatus of the present invention; and 
           [0042]      FIG. 17  shows the forth example of usage procedure for the analysis mesh generation apparatus of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0043]    In this specification, “to fillet” means “to add a fillet or fillets” and “to unfillet” means “to delete a fillet or fillets.” 
         [0044]      FIG. 1  shows a block diagram of an analysis mesh generation apparatus according to a first embodiment of the present invention. 
         [0045]    The analysis mesh generation apparatus includes a computer for generating a mesh mode. The computer includes an input/output device  101 , a targeted analysis mesh specification section  102 , a fillet information input section  104 , a fillet area shape generation section  106 , a fillet mesh addition/deletion section  108 , and a mesh display section  110 . 
         [0046]    The input/output device  101  includes devices, such as a keyboard, a pointing device, and a display, for a user of the apparatus to enter and view data. The targeted analysis mesh specification section  102  specifies a targeted analysis mesh model  103 . The fillet information input section  104  selects an edge for filleting the mesh model  103 , inputs a radius of the fillet applied to the selected edge, and stores the radius as fillet information data  105 . The fillet area shape generation section  106  generates a fillet face based on the fillet information data  105 , and generates fillet area shape data  107  from the fillet face and a face that is generated by extending an adjacent element face of the selected edge. The fillet mesh addition/deletion section  108  generates a filleted mesh model  109  that is obtained by adding or deleting the mesh for the area enclosed by the fillet area shape data  107  and the contour of the targeted analysis mesh model  103  specified by the mesh specification section  102 . The mesh display section  110  displays the filleted mesh model  109  on the input/output device  101 . 
         [0047]    In the first embodiment, the fillet information input section  104  selects a fillet face to be deleted from the targeted analysis mesh model  103  and stores the face as the fillet information data  105 . Based on the fillet information data  105 , the fillet area shape generation section  106  generates the fillet area shape data  107  from the fillet face and a face generated by extending an adjacent element face of the fillet face. The fillet mesh addition/deletion section  108  generates an unfilleted mesh model  109  that is obtained by adding or deleting the mesh for the area enclosed by the fillet area shape data  107  and the contour of the targeted analysis mesh model  103 . The mesh display section  110  displays the unfilleted mesh model  109  on the input/output device  101 . 
         [0048]    When a convex edge portion is selected to be filleted, the fillet mesh addition/deletion section  108  generates the filleted mesh model  109  by deleting the meshes in the area surrounded by the contour of the targeted analysis mesh model  103  and the fillet area shape data  107 . 
         [0049]    When a concave edge portion is selected to be filleted, the fillet mesh addition/deletion section  108  generates the filleted mesh model  109  by adding the meshes in the, area surrounded by the contour of the targeted analysis mesh model  103  and the fillet area shape data  107 . 
         [0050]    When a convex face portion is selected to be unfilleted, the fillet mesh addition/deletion section  108  generates the filleted mesh model  109  by adding the meshes in the area surrounded by the contour of the targeted analysis mesh model  103  and the fillet area shape data  107 . 
         [0051]    When a concave face portion is selected to be unfilleted, the fillet mesh addition/deletion section  108  generates the filleted mesh model  109  by deleting the meshes in the area surrounded by the contour of the targeted analysis mesh model  103  and the fillet area shape data  107 . 
         [0052]    The fillet information input section  104  specifies the number of divisions (division count) in a circumferential direction of the fillet, and stores the division count as the fillet information data  105 . The fillet area shape generation section  106  divides the fillet face in the fillet area shape data  107  based on the division count. 
         [0053]    The fillet information input section  104  specifies a threshold value for an edge extraction angle, extracts an element edge group, and selects the element edge group as an edge to be filleted. The element edge group includes element edges belonging to two adjacent exterior surface element faces that form a normal vector angle greater than or equal to the threshold value. 
         [0054]    The fillet information input section  104  recognizes characteristics of the targeted analysis mesh model  103 , and selects a boundary edge between characteristics as an edge to be filleted. 
         [0055]    The fillet information input section  104  recognizes characteristics of the targeted analysis mesh model  103 , and selects a fillet face for deleting characteristics. 
         [0056]    The following describes an example of the processes according to the first embodiment. 
         [0057]    With reference to  FIG. 2 , the processes of the targeted analysis mesh specification section  102  will be explained. An apparatus user uses the input/output device  101  to enter a file name of the targeted analysis mesh model  103  in an analysis mesh model input field  201  displayed in the input/output device in  FIG. 2 . A press of an OK button  202  leads to an input of the file corresponding to the file name entered in the analysis mesh model input field  201  as the analysis mesh model  103 . A press of a cancel button  203  leads to a cancel of the specification of the file name. 
         [0058]    With reference to  FIG. 3 , an example of adding a fillet by using the fillet information input section  104  will be described. The apparatus user uses the input/output device  101  to select edges to be filleted from an analysis mesh model display screen  301  displayed in the input/output device in FIG. 
         [0059]      3 . The selected edges are displayed in a fillet addition edge field  302  and are highlighted on the display screen  301 . The apparatus user enters a fillet radius in a fillet radius input field  303 . Generally, a radius is specified for each fillet and may be replaced by a diameter. A press of an OK button  304  leads to storing of both data entered in the fillet addition edge field  302  and the fillet radius input field  303  as the fillet information data  105 . When a fillet addition edge is specified, a press of an edge extraction button  305  leads to a display of a screen  306  so as to enter a threshold value for an edge extraction angle between normal vectors for adjacent meshes. Based on the entered value, the fillet information input section  104  extracts element edges from the targeted analysis mesh model  103  so that the element edges belong to two exterior surface element faces forming a normal vector angle greater than or equal to the threshold value. The extracted element edges may be highlighted so as to be selected as edges to be filleted. For example, if the edge extraction angle of  30  degrees is specified as the threshold value for the mesh model displayed on the analysis mesh model display screen  301 , the fillet information input section  104  extracts edges represented by thick lines  308 . If the angle of 10 degrees is specified, the fillet information input section  104  extracts edges represented by thick lines  309 . Further, it is possible, at the time when the edge extraction button  305  is pressed, to recognize characteristics of the targeted analysis mesh model  103 , highlight a boundary edge between the characteristics, and select edges to be filleted. For example, when the fillet information input section  104  recognizes characteristics of the analysis mesh model displayed on the analysis mesh model display screen  301  to extract a boundary edge between the characteristics, the fillet information input section  104  extracts edges represented by thick lines  310 . Further, a circumferential fillet division count input field  307  may be used to enter a division count in a circumferential direction of the fillet. Then, a press of an OK button  364  leads to storing of the fillet information data  105  that includes the data entered into the circumferential fillet division count input field  307  as well as the fillet addition edge field  302  and the fillet radius input field  303 . When a fillet is added, specifying a division count in the circumferential direction of the fillet makes it possible to control the fillet mesh density. 
         [0060]    With reference to  FIG. 4 , an example of deleting a fillet by using the fillet information input section  104  will be described. The apparatus user uses the input/output device  101  to select element faces for fillets to be deleted from the analysis mesh model display screen  401  displayed in the input/output device in  FIG. 4 . The selected element faces are displayed in a fillet deletion face field  402  and highlighted on the display screen  401 . When an OK button  403  is pressed, the data entered into the fillet deletion face field  402  is stored as the fillet information data  105 . When a face extraction button  404  is pressed, the fillet information input section  104  may recognize characteristics of the targeted analysis mesh model  103  and select the characteristics as a fillet face to be deleted. For example, when the fillet information input section  104  recognizes characteristics of the analysis mesh model displayed on the analysis mesh model display screen  401 , the analysis mesh model is classified into characteristics having edges as boundaries represented by thick lines  405 . 
         [0061]      FIG. 5  shows examples of PAD (Problem Analysis Diagram) for processes of the fillet area shape generation section  106 . The fillet area shape generation section  106  provides two types of processes depending on whether a fillet is added or deleted, as will be described below. 
         [0062]    With reference to  FIG. 6 , a process of the fillet area shape generation section  106  (S 500  in  FIG. 5 ) will be described in the case when a fillet is added. The fillet area shape generation section  106  reads edge group to be filleted, a fillet radius, and a circumferential division count from the fillet information data  105  (S 501  in  FIG. 5 ). The graphic  601  in  FIG. 6  shows emphasized edges to be filleted. The fillet area shape generation section  106  generates a fillet face (S 502  in  FIG. 5 ) for the edges by using a technique, such as Rolling Ball. The graphic  602  in  FIG. 6  shows the generated fillet face. If the circumferential division count is specified, the fillet area shape generation section  106  divides the fillet face by the specified division count (S 503  in  FIG. 5 ). The graphic  603  in  FIG. 6  shows the divided fillet faces. Then, the fillet area shape generation section  106  generates a face by extending the exterior surface element face that includes the beginning and end points (nodes) of the edge group to be filleted (S 504  in  FIG. 5 ). The graphic  604  in  FIG. 6  shows the extended face group. The fillet area shape generation section  106  extracts a spatially closed area from the fillet face, the targeted analysis mesh model  103 , and the extended face group (S 505  in  FIG. 5 ). The graphic  605  in  FIG. 6  shows the extracted closed area shape. The extracted closed area shape is stored as the fillet area shape data  107 . 
         [0063]    With reference to  FIG. 7 , a process of the fillet area shape generation section  106  (S 510  in  FIG. 5 ) will be described in the case when a fillet is deleted. The fillet area shape generation section  106  reads face group to be unfilleted from the fillet information data  105  (S 511  in  FIG. 5 ). The graphic  701  in  FIG. 7  shows emphasized faces to be unfilleted. The fillet area shape generation section  106  generates a face by extending the exterior surface element face adjacent to the fillet face (S 512  in  FIG. 5 ). The graphic  702  in  FIG. 7  shows the extended face group. Then, the fillet area shape generation section  106  extracts a spatially closed area from the fillet face and the extended face group ( 5513  in  FIG. 5 ). The graphic  703  in  FIG. 7  shows the closed area shape. The closed area shape is stored as the fillet area shape data  107 . 
         [0064]      FIGS. 8 and 9  show examples of PADs for processes of the fillet mesh addition/deletion section  108 . The fillet mesh addition/deletion section  108  provides four types of processes depending on whether a fillet is added or deleted or whether a portion to be added or deleted is concave or convex, as will described below. Two-dimensional sectional views are used in the examples for brief explanation. 
         [0065]    With reference to  FIG. 10 , processes of the fillet mesh addition/deletion section  108  will be described in the case when a convex edge is filleted (S 800  in  FIG. 8 ). 
         [0066]    The fillet mesh addition/deletion section  108  extracts element group interfering with the fillet area shape data from the analysis meshmodel (S 801  in  FIG. 8 ). In  FIG. 10 , the graphic  1001  shows the analysis mesh model. The graphic  1002  shows the fillet area shape data. The graphic  1003  shows the interfering element group. The fillet mesh addition/deletion section  108  searches interfering elements in the element faces in the interfering element group and extracts an element face that has one interfering element as a boundary element face (S 802  in  FIG. 8 ). The graphic  1004  in  FIG. 10  shows the extracted boundary element face. The fillet mesh addition/deletion section  108  extracts a closed area from the boundary element face and a fillet face shape for the fillet area shape data  107  (S 803  in  FIG. 8 ). The graphic  1005  in  FIG. 10  shows, the extracted closed area. The fillet mesh addition/deletion section  108  generates a mesh for the closed area (S 804  in FIG.  8 ) as shown by the graphic  1006  in  FIG. 10 . The fillet mesh addition/deletion section  108  deletes the interfering element group from the analysis mesh model (S 805  in  FIG. 8 ) as shown by the graphic  1007  in  FIG. 10 . The fillet mesh addition/deletion section  108  combines the analysis mesh model with the mesh generated for the closed area (S 806  in  FIG. 8 ). The resulting mesh model is stored as a filleted/unfilleted mesh model  109 . The graphic  1008  in  FIG. 10  shows a filleted mesh model. Consequently, filleted meshes can be generated for a convex edge. The process is applied only to the element interfering with the fillet. Therefore, nothing affects the meshes of the elements independent of the fillet, ensuring a high-speed process. 
         [0067]    With reference to  FIG. 11 , processes of the fillet mesh addition/deletion section  108  will be described in the case when a concave edge is filleted (S 810  in  FIG. 8 ). 
         [0068]    The fillet mesh addition/deletion section  108  extracts element group in contact with the fillet area shape data from the analysis meshmodel (S 811  in  FIG. 8 ). In  FIG. 11 , the graphic  1101  shows the analysis mesh model. The graphic  1102  shows the fillet area shape data. The graphic  1103  shows the element group in contact with the fillet area shape data. The fillet mesh addition/deletion section  108  generates a fillet mesh for the fillet area shape data (S 812  in  FIG. 8 ). The graphic  1104  in  FIG. 11  shows meshes generated for the fillet area shape data. The fillet mesh addition/deletion section  108  searches elements in contact with the fillet area shape data in the element faces in the element group in contact with the fillet area shape data. The fillet mesh addition/deletion section  108  extracts an element face that has one element in contact with the fillet area shape data as a boundary element face (S 813  in  FIG. 8 ). The graphic  1105  in  FIG. 11  shows the extracted boundary element face. The fillet mesh addition/deletion section  108  extracts a closed area from the boundary element face and the element faces other than the fillet faces of the fillet meshes in contact with the fillet area shape data (S 814  in  FIG. 8 ). The graphic  1106  in  FIG. 11  shows the extracted closed area. The fillet mesh addition/deletion section  108  generates meshes  1107  in  FIG. 11  for the closed area (S 815  in  FIG. 8 ). The fillet mesh addition/deletion section  108  further deletes element group in contact with the fillet area shape data from the analysis mesh model (S 816  in  FIG. 8 ) as shown by the graphic  1108  in  FIG. 11 . The fillet mesh addition/deletion section  108  combines the analysis mesh model with the meshes generated for the closed area (S 817  in  FIG. 8 ). The resulting mesh model is stored as the filleted/unfilleted mesh model  109 . The graphic  1109  in  FIG. 11  shows a filleted mesh model. Consequently, filleted meshes can be generated for a concave edge. The process is applied only to the element in contact with the fillet. Therefore, nothing affects the meshes of the elements independent of the fillet, ensuring a high-speed process. 
         [0069]    With reference to  FIG. 12 , processes of the fillet mesh addition/deletion section  108  will be described in the case when a convex portion is unfilleted (S 900  in  FIG. 9 ). 
         [0070]    The fillet mesh addition/deletion section  108  generates a fillet mesh for the fillet area shape data  107  (S 901  in  FIG. 9 ). In  FIG. 12 , the graphic  1201  shows the analysis mesh model. The graphic  1202  shows the fillet area shape data. The graphic  1203  shows the meshes generated for the fillet shape data. The fillet mesh addition/deletion section  108  combines the analysis mesh model with the fillet mesh (S 902  in  FIG. 9 ). The resulting mesh model is stored as the filleted/unfilleted mesh model  109 . The graphic  1204  in  FIG. 12  shows the filleted mesh model. Thus, the meshes which the fillets in the convex portion are deleted from can be generated. 
         [0071]    With reference to  FIG. 13 , processes of the fillet mesh addition/deletion section  108  will be described in the case when a concave portion is unfilleted (S 910  in  FIG. 9 ). 
         [0072]    The fillet mesh addition/deletion section  108  extracts element group interfering with the fillet area shape data from the analysis mesh model (S 911  in  FIG. 9 ). In  FIG. 13 , the graphic  1301  shows the analysis mesh model. The graphic  1302  shows the fillet area shape data. The graphic  1303  shows the element group interfering with the fillet area shape data. The fillet mesh addition/deletion section  108  searches interfering elements in the element faces in the interfering element group and extracts an element face that has one interfering element as a boundary element face (S 912  in  FIG. 9 ). The graphic  1304  in  FIG. 13  shows the extracted boundary element face. The fillet mesh addition/deletion section  108  extracts a closed area from the boundary element face and the shape other than the fillet faces of the fillet area shape data (S 913  in  FIG. 9 ). The graphic  1305  in  FIG. 13  shows the extracted closed area. The fillet mesh addition/deletion section  108  generates meshes  1306  in  FIG. 13  for the closed area (S 914  in  FIG. 9 ). The fillet mesh addition/deletion section  108  deletes interfering element group from the analysis mesh model  1301  (S 915  in  FIG. 9 ) as shown by the graphic  1307  in  FIG. 13 . The fillet mesh addition/deletion section  108  combines the analysis mesh model with the mesh generated for the closed area (S 916  in  FIG. 9 ). The resulting mesh model is stored as the filleted/unfilleted mesh model  109 . The graphic  1308  in  FIG. 13  shows the unfilleted mesh model. Consequently, the meshes which fillets in the concave portion are deleted from can be generated. The process is applied only to the element interfering with the fillet. Therefore, nothing affects the meshes of the elements independent of the fillet, ensuring a high-speed process. 
         [0073]    With reference to  FIG. 14 , the first example of usage procedure will be described for the analysis mesh generation apparatus of the present invention. A targeted analysis mesh model  1401  is shown in  FIG. 14 . This example describes an addition of a fillet to the analysis mesh model  1401  at the edge group indicated by thick lines  1402 . The fillet has a radius of 5 mm and a circumferential division count of 2. 
         [0074]    Using the screens displayed by the targeted analysis mesh specification section  102  and the fillet information input section  104 , the apparatus user enters the radius of 5 mm and the circumferential division count of 2 as the targeted analysis mesh model and the fillet information at the edges indicated by thick lines  1402  in  FIG. 14 . The fillet area shape generation section  106  of the apparatus generates fillet shape data using the targeted analysis mesh model and the fillet information data. The generated fillet shape data  1403  is shown in  FIG. 14 . The fillet mesh addition/deletion section  108  of the apparatus generates a filleted mesh model using the targeted analysis mesh model and the fillet shape data. The filleted mesh model  1404  is shown in  FIG. 14 . 
         [0075]    In this manner, a fillet can be directly added to the analysis mesh model and therefore the apparatus of the present invention can reduce the processes for the analysis model generation. 
         [0076]    With reference to  FIG. 15 , the second example of usage procedure will be described for the analysis mesh generation apparatus of the present invention. A targeted analysis mesh model  1501  is shown in  FIG. 15 . This example describes an addition of a fillet to the analysis mesh model  1501  at the edge group indicated by thick lines  1502 . The fillet has a radius of 5 mm and a circumferential division count of 3. 
         [0077]    Using the screens displayed by the targeted analysis mesh specification section  102  and the fillet information input section  104 , the apparatus user enters the radius of 5 mm and the circumferential division count of 3 as the targeted analysis mesh model and the fillet information at the edges indicated by thick lines  1502  in  FIG. 15 . The fillet area shape generation section  106  of the apparatus generates fillet shape data using the targeted analysis mesh model and the fillet information data. The generated fillet shape data  1503  is shown in  FIG. 15 . The fillet mesh addition/deletion section  108  of the apparatus generates a filleted mesh model using the targeted analysis mesh model and the fillet shape data. The filleted mesh model  1504  is shown in  FIG. 15 . 
         [0078]    In this manner, a fillet can be directly added to the analysis mesh model and therefore the apparatus of the present invention can reduce the processes for the analysis model generation. 
         [0079]    With reference to  FIG. 16 , the third example of usage procedure will be described for the analysis mesh generation apparatus of the present invention. A targeted analysis mesh model  1601  is shown in  FIG. 16 . This example describes a deletion of a fillet from the analysis mesh model  1601 . The fillet is of the face group enclosed by thick lines  1602   
         [0080]    Using the screens displayed by the targeted analysis mesh specification section  102  and the fillet information input section  104 , the apparatus user enters the face group enclosed by thick lines  1602  as the targeted analysis mesh model and the fillet information in  FIG. 16 . The fillet area shape generation section  106  of the apparatus generates fillet shape data using the targeted analysis mesh model and the fillet information data. The generated fillet shape data  1603  is shown in  FIG. 16 . The fillet mesh addition/deletion section  108  of the apparatus generates an unfilleted mesh model using the targeted analysis mesh model and the fillet shape data. The unfilleted mesh model  1604  is shown in  FIG. 16 . 
         [0081]    In this manner, a fillet can be directly deleted from the analysis mesh model and therefore the apparatus of the present invention can reduce the processes for the analysis model generation. 
         [0082]    With reference to  FIG. 17 , the forth example of usage procedure will be described for the analysis mesh generation apparatus of the present invention. A targeted analysis mesh model  1701  is shown in  FIG. 17 . This example describes a deletion of a fillet of the hatched face group  1702  from the analysis mesh model  1701 . 
         [0083]    Using the screens displayed by the targeted analysis mesh specification section  102  and the fillet information input section  104 , the apparatus user enters the hatched face group  1702  as the targeted analysis mesh model and the fillet information in  FIG. 17 . The fillet area shape generation section  106  of the apparatus generates fillet shape data using the targeted analysis mesh model and the fillet information data. The generated fillet shape data  1703  is shown in  FIG. 17 . The fillet mesh addition/deletion section  108  of the apparatus generates an unfilleted mesh model using the targeted analysis mesh model and the fillet shape data. The unfilleted mesh model  1704  is shown in  FIG. 17 . 
         [0084]    In this manner, a fillet can be directly deleted from the analysis mesh model and therefore the apparatus of the present invention can reduce the processes for the analysis model generation.