JPH07219984A - Optimal design system for rib-reinforced products - Google Patents

Abstract

PURPOSE:To provide an optimum design system for a rib-reinforced product which can solve a problem of stress concentration and design a product by optimum rib reinforcement. CONSTITUTION:The optimum design system is provided with a rigidity analyzing part 1 for repeating processing for executing rigidity analysis for a shape model removing all ribs, forming a rib on a part on which its maximum deflection exceeds a tolerance and executing rigidity analysis again until the maximum deflection is included within the tolerance and a strength analyzing part 2 for executing strength analysis based upon the shape model obtained by the analysis of the analyzing part 1, reinforcing the part on which its maximum stress exceeds a tolerance, executing strength analysis again, and repeating strength analysis until the reinforced part is included with the tolerance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optimal design system for a product to be reinforced by ribs, and is used in the field of computer assisted CAE.

[0002]

2. Description of the Related Art In the field of injection molding and the like, when a single product is made, conventionally, it is necessary to make a temporary decision on the product by means of a die to judge whether the product is good or bad, and to determine whether the product is good or bad. In some cases, a process such as attaching ribs is performed, and product design is redone.

However, due to the recent development of the CAE field in which computer support is provided, it is possible to design an optimum product by simulation without temporarily hitting an actual product.

As such a simulation device,
For example, there is an optimized design data output device for thin plate-shaped products disclosed in Japanese Patent Application No. 3-196462.

In this device, when a thin plate-shaped product having a reinforcing rib and a reinforcing bolt leg on the bottom surface is used as an initial design product, a displacement amount of each part is applied by applying a load to each part of the initial design product. And a first structural analysis unit that compares the maximum displacement amount with a reference value set in advance, and the maximum displacement amount obtained by the first structural analysis unit exceeds the reference value. If there is, the structural sensitivity analysis unit that determines the degree of influence when changing design variables such as the plate thickness of each part of the initial design product, the elastic modulus based on the displacement amount of each part,
A first design correction unit that determines the weakest portion of the initial design product based on the degree of influence obtained by the structural sensitivity analysis unit, and provides the bolt leg to the determined weakest portion for reinforcement. A second structural analysis unit for performing a structural analysis of the design product modified by the first design modification unit to obtain the maximum displacement amount, and a strength of the design product reinforced by the first design modification unit. A second design correction portion for reinforcing the rib height and wall thickness of the initial design product until the strength is almost the same, and data showing the design product modified by the second design correction portion, and And a data output unit that outputs data indicating the design product corrected by the first design correction unit.

That is, a series of systems in which the structural analysis and the structural sensitivity analysis are associated under a certain condition are constructed, and the comparison result between the reinforcement by the bolt leg and the reinforcement by the height of the rib and the wall thickness is used as numerical data. It is configured to output.

[0007]

However, in the optimized design data output device having the above structure, the problem of stress concentration due to the reinforcement of ribs is not taken into consideration.

The present invention was devised to solve such problems, and the purpose thereof is to solve the problem of stress concentration and to optimize the rib-reinforced product which enables product design by optimal rib reinforcement. To provide a design system.

[0009]

In order to solve the above-mentioned problems, the optimum design system for a rib-reinforced product of the present invention performs rigidity analysis on a shape model excluding all ribs, and the maximum deflection is within an allowable range. Based on the rigidity analysis part that repeats the process of forming a rib in the exceeded part and performing rigidity analysis again until the maximum deflection is within the allowable range, and the shape model obtained by the analysis in this rigidity analysis part. Strength analysis is performed, the part where the maximum stress exceeds the allowable range is reinforced, the strength analysis is performed again, and the strength analysis part that repeats the strength analysis until the reinforced part is within the allowable stress range is provided. The shape model obtained by the analysis in the strength analysis unit is designed as a final product.

Further, the optimum design system for a rib-reinforced product of the present invention performs rigidity analysis on a shape model excluding all ribs, forms ribs in a portion where the maximum deflection exceeds the allowable range, and again. The strength analysis is performed based on the rigidity analysis unit that repeatedly performs processing such as rigidity analysis until the maximum deflection is within the allowable range, and the shape model obtained by the analysis in this rigidity analysis unit, and the maximum stress is within the allowable range. If the part exceeding the allowable stress is near the rib, the rib is reinforced, while if the part exceeding the allowable stress is not near the rib, a rib is formed on the part exceeding the allowable stress. Then, the strength analysis is carried out again, and the strength analysis section for repeatedly performing the strength analysis until the portion reinforced in this way is within the allowable stress range is obtained by the analysis in this strength analysis section. It is intended to design the Jo model as a final product.

[0011]

The operation of the invention described in claim 1 will be described.

In designing a product to be reinforced with ribs, the rigidity analysis section first performs rigidity analysis using a shape model excluding all ribs, and forms ribs in the part where the maximum deflection exceeds the allowable range. Then, the process of performing rigidity analysis again is repeated until the maximum deflection falls within the allowable range. As a result, the optimum rib for obtaining the rigidity as a product is formed.

In the strength analysis section, strength analysis is performed based on the shape model obtained by the analysis in the rigidity analysis section,
The portion where the maximum stress exceeds the allowable range is reinforced and the strength analysis is performed again, and the strength analysis is repeated until the reinforced portion is within the allowable stress range. As a result, optimum reinforcement for obtaining the strength as a product is achieved.

As a result, the problem of concentrated stress is solved, and optimum ribs for obtaining the rigidity and strength of the final product are formed.

The operation of the invention described in claim 2 will be described.

In designing a product to be reinforced with ribs, the stiffness analysis section first conducts a stiffness analysis using a shape model excluding all ribs, and forms ribs in the part where the maximum deflection exceeds the allowable range. Then, the process of performing rigidity analysis again is repeated until the maximum deflection falls within the allowable range. As a result, the optimum rib for obtaining the rigidity as a product is formed.

In the strength analysis section, strength analysis is performed based on the shape model obtained by the analysis in the rigidity analysis section.
When the maximum stress exceeds the allowable range, if the portion exceeding the allowable stress is near the rib, the rib is reinforced, while the portion exceeding the allowable stress is near the rib. A rib is newly formed in the portion that exceeds the limit and strength analysis is performed again. In this way, the strength analysis is repeated until the reinforced portion is within the allowable stress range. As a result, optimum reinforcement for obtaining the strength as a product is achieved.

As a result, the problem of concentrated stress is solved, and optimal ribs for obtaining the rigidity and strength of the final product are formed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the electrical construction of an optimum design system for a rib-reinforced product according to the present invention.

In the same figure, a shape model excluding all ribs of a product to be designed is given as input data to the rigidity analysis section 1 for reinforcement by ribs, and the output of this rigidity analysis section 1 is Strength analysis part 2 for reinforcement by ribs
Have been led to. Then, from the strength analysis unit 2, a final shape model in which optimum ribs for obtaining rigidity and strength as a final product are formed is output as design data.

The stiffness analysis unit 1 performs a stiffness analysis on the input shape model, forms a rib in a portion where the maximum deflection exceeds the allowable range, and performs the stiffness analysis again. It is a block that is repeatedly executed until it is within the allowable range.

In addition, the strength analysis unit 2 uses the rigidity analysis unit 1
Strength analysis is performed based on the shape model obtained by the analysis in 1., and the process of reinforcing the part where the stress exceeds the allowable range and performing strength analysis again, until the reinforced part is within the allowable stress range. It is a repeating block.

Next, the operation of the optimal design system for rib-reinforced products constructed as described above will be described with reference to the flow charts shown in FIGS.

First, a shape model obtained by removing all ribs from a product to be designed is given to the rigidity analysis section 1 as input data (step S1).

Further, the rigidity analysis unit 1 is input with the maximum deflection allowable value based on the given shape model, and the strength analysis unit 2 is input with the allowable stress reference value (step S2). ). Here, the maximum deflection allowable value and the reference value of the allowable stress are usually determined by the design standard for the product.

After that, the rigidity analysis by the rigidity analysis unit 1 is started (step S3). That is, rigidity analysis is performed using a shape model excluding all ribs. As a result, if the maximum deflection is within the allowable range, the process proceeds to the next strength analysis (steps S4 and S10).

On the other hand, when the maximum deflection exceeds the permissible range, ribs are formed in the portion where the maximum deflection exceeds the permissible range and rigidity analysis is performed again (step S4).
S5, S6). That is, the position of the formed rib and the thickness of the rib are adjusted to perform a sensitivity analysis for checking the degree of influence (steps S7 and S8), and as a result, it is determined whether or not the maximum deflection is within the allowable range. (Step S9).

Here, with respect to the position adjustment of the rib in step S7, as shown in FIG. 4, when the thickness of the rib 3 is set to t, the adjustment is made within the range of 3t indicated by the diagonal lines in the figure. . Further, the rib thickness is adjusted within a range of about ± 10% with respect to the thickness t of the formed rib, for example.

In the rigidity analysis unit 1, such step S
The processing from 5 to step S9 is repeated until the maximum deflection falls within the allowable range. As a result, the optimum rib for obtaining the rigidity as a product is formed.

As a result of the rigidity analysis, if the maximum deflection is within the allowable range, then the strength analysis is started (step S1).
0).

That is, the strength analysis section 2 performs strength analysis based on the shape model obtained by the analysis in the rigidity analysis section 1. As a result, if the maximum stress is within the allowable range,
At that point, all the processes are finished (step S11).
Then, the shape data at that time is output as design data of the final product (for example, printout as a design drawing or screen display).

On the other hand, when the maximum stress exceeds the allowable range, if the portion exceeding the allowable stress is near the rib, the rib is reinforced (steps S12 and S1).
7, S18), if the portion exceeding the allowable stress is not in the vicinity of the rib, a new rib is formed in the exceeding portion and the strength analysis is performed again (steps S12, S13, S1).
4). The determination as to whether or not the position is near the rib in step S12 is similar to the range shown in FIG. 4 regarding the position adjustment of the rib. That is, if it is within the range of 3t indicated by hatching in the figure, it is determined that the rib 3 is in the vicinity.

Here, when proceeding from step S12 to steps S18 and S14, it is judged whether or not the number of times of repetition is within the allowable number (step S13,
S17). Step S13 is the number of times the strength analysis can be repeated by forming ribs.
Is the allowable number of repetitions of the strength analysis by adding R to the root of the rib.

The allowable number of times of repetition is calculated by the following equation (1).

[0036]

[Equation 1]

However, although there is no particular optimum value for the reference value of the equation (1), considering the processing time in the computer, it is about 0.001 to 0.03 (1 to
3%) is preferable.

When a rib is newly formed in a portion exceeding the allowable range (step S14), the position of the formed rib and the rib wall thickness are adjusted (step S1).
5, S16), the strength analysis is performed again (step S1).
0), it is again judged whether the maximum stress is within the allowable range (step S11).

Here, regarding the position adjustment of the rib in step S15, when the thickness of the rib is t, as in the case shown in FIG. 4 described above, it is within the range of 3t indicated by diagonal lines in the figure. Adjust. Further, the rib thickness adjustment is performed within a range of about ± 10% of the thickness t of the formed rib.

On the other hand, since the portion exceeding the allowable stress is in the vicinity of the rib, when reinforcing the rib, R is attached to the root of the rib where the maximum stress is generated (step S18). Then, the R of the rib is adjusted (step S19), and the strength analysis is performed again (step S10).
It is again determined whether the maximum stress is within the allowable range (step S11).

The above processing (steps S10, S11, S
12, S17, S18, S19) is repeatedly performed, and when the allowable number of repetitions based on the above equation (1) is exceeded in step S17, the operation proceeds from step S20 to step S21, and the maximum stress A process is performed to fill the base of the rib that has occurred to the height of the rib. Then, the rib filling height is adjusted (step S22), the strength analysis is performed again (step S10), and it is determined again whether the maximum stress is within the allowable range (step S).
11). Here, the allowable repetition number of times of step S20 is the allowable repetition number of the strength analysis by filling the rib root up to the rib height.

The above processing (steps S10, S11, S
12, S17, S20, S21, S22) is repeatedly performed, and as a result, in Step S20, when the allowable number of repetitions based on the above formula (1) is exceeded, the operation is terminated at that time. Then, the shape data at that time is output as design data of the final product (for example, printout as a design drawing or screen display).

By repeating the strength analysis until the reinforced portion is within the allowable stress range in this manner, optimum rib reinforcement for obtaining the strength as a product can be obtained.

As a result, the problem of stress concentration is solved, and a shape model having optimum ribs for obtaining rigidity and strength as a final product can be obtained.

[0045]

The optimum design system for a rib-reinforced product according to the present invention performs rigidity analysis on a shape model excluding all ribs, and forms ribs in a portion where the maximum deflection exceeds the allowable range. The strength analysis is performed based on the rigidity analysis section that repeatedly performs the processing such as rigidity analysis until the maximum deflection is within the allowable range, and the shape model obtained by the analysis in this rigidity analysis section, and the maximum stress is allowed. Since the structure is equipped with a strength analysis part that reinforces the part that exceeds the range and repeats the strength analysis and repeats the strength analysis until the reinforced part is within the allowable stress range, the problem of stress concentration is solved. In addition, it is possible to efficiently perform product design by optimal rib reinforcement that satisfies the criteria of rigidity and strength.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an optimum design system for a rib-reinforced product according to the present invention.

FIG. 2 is a flow chart for explaining the operation of the optimum design system for rib-reinforced products according to the present invention.

FIG. 3 is a flow chart for explaining the operation of the optimum design system for rib-reinforced products according to the present invention.

FIG. 4 is a diagram showing an adjustable range of a formed rib position and a range in which a maximum stress is determined in the vicinity of the rib.

[Explanation of symbols]

 1 Stiffness analysis section 2 Strength analysis section

Claims (2)

[Claims] 1. A design system for a product that is reinforced by ribs, wherein rigidity analysis is performed using a shape model excluding all ribs, and ribs are formed in a portion where the maximum deflection exceeds the allowable range. Rigidity analysis is performed again based on the rigidity analysis section that repeatedly performs processing such as rigidity analysis until the maximum deflection falls within the allowable range, and the shape model obtained by the analysis in this rigidity analysis section. The strength analysis section was reinforced by strengthening the part exceeding the range, and the strength analysis was repeated until the reinforced part was within the allowable stress range. Optimal design system for rib-reinforced products, characterized by designing shape models as final products. 2. A design system for a product that is reinforced by ribs, wherein rigidity analysis is performed using a shape model excluding all ribs, and ribs are formed in a portion where the maximum deflection exceeds the allowable range. Rigidity analysis is performed again based on the rigidity analysis section that repeatedly performs processing such as rigidity analysis until the maximum deflection falls within the allowable range, and the shape model obtained by the analysis in this rigidity analysis section. When exceeding the allowable range, if the part that exceeds the allowable stress is near the rib, the rib is reinforced, while if the part that exceeds the allowable stress is not near the rib, add a rib to the exceeding part. The strength analysis part is formed to repeat strength analysis until the strength of the part reinforced in this way is within the allowable stress range. Optimal design system for rib-reinforced products, characterized by designing the finished shape model as the final product.