JP2020125969A - Parameter acquisition method and sand mold single shear tester - Google Patents

Abstract

To acquire the parameter used for numerical analyses relating to the single shear of a sand mold under high temperature, and provide a single shear tester with which it is possible to test the single shear of the sand mold under high temperature.SOLUTION: A parameter acquisition method of the present invention acquires the parameter used for numerical analyses relating to the single shear of a sand mold. The parameter acquisition method includes: a setting step (S1) for determining the setting condition of the sand mold; a test step (S2) for performing a single shear test on a sand mold test piece which is vertically splittable and accommodated in a container under a plurality of high temperatures using the setting condition determined in the setting step (S1); and a parameter calculation step (S3) for creating a strength envelope for each of the plurality of temperatures on the basis of the measurement result obtained by the test step (S2) assuming that the sand mold follows a specific strength envelope, and thereby calculating a parameter.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for obtaining parameters used in a numerical analysis regarding a single shear of a sand mold, and a single shear test device for a sand mold.

2. Description of the Related Art Conventionally, in the design of civil engineering fields, a sand type single-sided shear test has been performed in order to obtain the shear strength of soil or sand (sand type). In this one-sided shear test, a sand-type test piece is housed in a one-sided shear tester, and the shear strength of the sand-type mold is measured.

An example of the above-mentioned one-sided shear testing device is a one-sided shear testing device provided with a vertically divided storage box (see FIG. 4 of Patent Document 1). In this one-sided shear test device, a sand-type test piece is stored in a storage box, and a constant vertical load is applied to the upper storage box, and the shear stress is applied to the test piece by horizontally moving the upper storage box. Let it work. At this time, it becomes possible to measure the shear strength of the test piece by measuring the shear stress generated in the test piece with a load measuring device and measuring the vertical displacement and horizontal displacement of the upper housing box respectively with the displacement measuring device. ing.

JP-A-8-226886

Numerical analysis such as FEM (Finite Element Method) analysis is used in the design of the sand mold. In the FEM analysis, by creating an analysis model of the sand mold and inputting various parameters, it is possible to predict the dimensional change and the like during the solidification shrinkage of the sand mold. In order to perform such a numerical analysis, it is necessary to acquire various parameters such as shear stress and vertical stress acting on the sand mold from the measurement result of the one-way shear test by the above-mentioned one-way shear test device.

However, since the above-mentioned one-sided shear tester measures the shear strength of the sand mold at room temperature, there is a problem that the shear strength of the sand mold cannot be measured at high temperatures. Therefore, there is a problem that it is not possible to acquire the parameters used for the numerical analysis regarding the direct shear of the sand mold under high temperature.

One aspect of the present invention has been made in view of the above-described problems, and an object thereof is to obtain parameters used for a numerical analysis regarding a direct shear of a sand mold under high temperature. Further, it is an object of the present invention to provide a single-sided shear tester capable of performing a sand-type single-sided shear test under high temperature.

A method for acquiring parameters according to an aspect of the present invention made to solve the above problems is a method for acquiring parameters used for numerical analysis regarding one-sided shear of a sand mold, and a setting including a temperature and a physical property value of the sand mold. Using a setting step that determines the conditions and the setting conditions determined by the setting step, under a plurality of temperatures, a one-sided shear test is performed on the sand-type test piece housed in the vertically divisible container. As a test step and the sand mold follows a predetermined strength envelope, by creating the strength envelope for each of a plurality of temperatures based on the measurement results obtained by the test step, the parameter calculation for calculating the parameters And a process.

According to the parameter acquisition method described above, a sand mold single-face shear test is performed at a plurality of temperatures in a test process, and based on the measurement results obtained in the test process, parameters are calculated at a plurality of temperatures in each process. By creating a strength envelope in, various parameters to be used for numerical analysis of one-sided shear of sand mold can be acquired for each of a plurality of temperatures.

Further, in the parameter acquisition method according to one aspect of the present invention, the setting conditions determined in the setting step include a magnitude of a load applied to the sand mold in the axial direction, and a shear displacement amount of the sand mold. The measurement results obtained in the test step include shear stress of the sand mold under a plurality of temperatures, vertical stress of the sand mold, and vertical displacement, and are calculated in the parameter calculation step. The parameters include the adhesive force of the sand mold for each temperature, the internal friction angle of the sand mold, and the expansion angle of the sand mold.

According to the parameter acquisition method described above, based on the shear stress of the sand mold under a plurality of temperatures obtained in the test process, the vertical stress of the sand mold, and the measurement result of the vertical displacement amount, in the parameter calculation process, for each temperature. The adhesive force of the sand mold, the internal friction angle of the sand mold, and the expansion angle of the sand mold can be calculated. As a result, the adhesive force of the sand mold, the internal friction angle, and the expansion angle for each temperature can be input as parameters to the numerical analysis regarding the one-sided shear of the sand mold, and a good numerical analysis result can be obtained.

Further, in the parameter acquisition method according to one aspect of the present invention, the temperature of the sand mold under the set conditions includes a high temperature of at least 100° C. or higher.

According to the above-described parameter acquisition method, it is possible to perform a numerical analysis on the face shear of the sand mold at a high temperature of 100° C. or higher, and to predict the strength of the sand mold at a high temperature with high accuracy.

Further, in the parameter acquisition method according to an aspect of the present invention, the strength envelope created in the parameter calculation step is created by complementing a non-measured portion from the measurement result obtained in the test step. It is characterized by

According to the above-mentioned parameter acquisition method, based on the measurement result obtained in the test process, the strength envelope can be created by complementing the range (non-measurement part) not measured in the test process. .. This can reduce the number of direct shear tests in the test process necessary to acquire the parameters.

A sand-type single-sided shear test apparatus according to an aspect of the present invention is a sand-type single-sided shear test apparatus, which is a vertically divisible container for housing the sand-shaped test piece, and the test piece in the container. A heater that heats the test piece, a first pressurizing section that applies a load to the test piece in the container from a first direction, and a first pressurizing section that is loaded with a load. A second pressurizing unit that applies a load to the test piece in the container on one side from a second direction orthogonal to the first direction, and a load applied to the test piece by the first pressurizing unit. A first load sensor for measuring, a second load sensor for measuring shear stress generated in the test piece loaded by the second pressurizing section, and a test for applying load by the second pressurizing section And a shear displacement sensor for measuring the shear displacement amount of the piece.

According to the above-mentioned sand-type single-sided shear test apparatus, the load is applied from the first direction (axial direction) to the test piece in the container by the first pressurizing unit, and the test piece in the container by the second pressurizing unit. By applying a load to the test piece from the second direction (side surface direction), a desired shear stress can be applied to the test piece to perform a sand-type one-sided shear test. In particular, since the test piece in the container can be heated to a high temperature by the heater, the sand mold single-face shear test can be performed at a high temperature. Thereby, the shear strength of the sand mold can be measured under a plurality of temperatures including high temperatures.

According to the parameter acquisition method of one aspect of the present invention, it is possible to acquire the parameters used for the numerical analysis regarding the direct shear of the sand mold under high temperature.

Further, according to the sand mold single plane shear test apparatus of one aspect of the present invention, the sand mold single plane shear test can be performed at a high temperature.

It is a schematic diagram of a one-sided shear test device concerning an embodiment of the present invention. It is a figure which shows an example of the intensity envelope of the sand mold which concerns on embodiment. It is a conceptual diagram which shows the expansion angle of the sand mold which concerns on embodiment. It is a flow chart which shows a flow of a method of acquiring a parameter concerning an embodiment. It is a flow chart which shows the flow of the one-sided shear test by the one-sided shear test device concerning an embodiment. It is a graph which shows the relationship between the amount of shear displacement by the one-sided shear test which concerns on embodiment, and the stress measured with a load sensor. It is a graph which shows the relationship between the amount of shear displacement by a one-sided shear test concerning an embodiment, and the amount of vertical displacement. It is a graph which shows an example of the intensity envelope created based on the measurement result obtained by the one-sided shear test concerning an embodiment. It is the figure which compared the analysis value of the numerical analysis using the parameter calculated by the parameter acquisition method which concerns on embodiment, and the experimental value.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

[One-way shear tester]
First, a single-sided shear test device 1 for performing a sand-type single-sided shear test will be described with reference to FIG. FIG. 1 is a schematic diagram of a one-sided shear test apparatus 1 of this embodiment. As shown in FIG. 1, the one-sided shear test apparatus 1 includes a housing 100, a container 10, a first pressing portion 21, a contact member 21 a, a contact member 21 b, and a second pressing portion 22. , First cylinder 31, second cylinder 32, first upper load sensor 41 (first load sensor), first lower load sensor 42 (first load sensor), second load sensor 43, and shear displacement The sensor 44, the heaters 51 and 52, and the guide 60 are provided.

In the one-sided shear test by the one-sided shear test apparatus 1, the sand type test piece TP is housed in the container 10, and the second pressurizing section TP is loaded with the load from the axial direction by the first pressurizing unit 21. It is a device that applies a shear stress to the test piece TP by applying a load to the test piece TP from the side surface direction by the pressurizing unit 22. Hereinafter, for convenience of description, the bottom surface side of the housing 100 in FIG. 1 is the lower side, the first cylinder 31 side is the upper side, the second cylinder 32 side is the right side, and the side opposite to the second cylinder 32 is the left side.

The housing 100 is a rectangular box-shaped member, and is partitioned vertically by a partition plate 101. The container 10 is arranged inside the housing 100. The container 10 is a container for containing a predetermined amount of sand-shaped test pieces TP. As the test piece TP, for example, a cylindrical shape having a diameter of 50 mm and a height of about 50 mm is used. The size and shape of the container 10 can be appropriately changed in design depending on the test piece TP.

The container 10 has an upper container 11 and a lower container 12, and is configured to be divided into an upper container 11 and a lower container 12. The upper container 11 is fixed to the partition plate 101. The upper and lower surfaces of the upper container 11 are open. The upper surface side of the lower container 12 is open and the lower surface side is closed.

The upper container 11 and the lower container 12 are integrated before the above-mentioned one-sided shear test. On the other hand, when performing the one-sided shear test, it is divided into an upper container 11 and a lower container 12. The lower container 12 divided into two parts can be moved to the left side direction along the guide 60 by being pressed by the second pressing part 22 described later. The guide 60 is fixed to the bottom surface of the housing 100 and slidably supports a contact member 21b described later.

Note that the container 10 does not have to be configured to be vertically separable, and may be appropriately modified in design as long as the test piece TP in the container 10 can be subjected to shear stress.

The first pressurizing unit 21 is, for example, a rod-shaped member, and applies a load to the test piece TP in the container 10 from the axial direction (first direction) via the contact member 21a. A first cylinder 31 is provided above the first pressurizing unit 21. The first cylinder 31 moves the first pressurizing unit 21 in the axial direction based on a control signal from a control device (not shown).

A contact member 21b is provided between the lower container 12 and the guide 60. The contact member 21b is, for example, a rod-shaped member, and is a member for connecting the lower container 12 and the guide 60. When a load is applied downward to the container 10 by the first pressurizing unit 21, a load (reaction force) is applied to the lower container 12 from the guide 60 side via the contact member 21b.

The second pressurizing unit 22 is a rod-shaped member and applies a load to the test piece TP in the lower container 12 from the side surface direction (second direction). A second cylinder 32 is provided on the right side of the second pressure unit 22. The 2nd cylinder 32 moves the 2nd pressurization part 22 to the side surface left direction based on the control signal from the said control apparatus.

As the first cylinder 31 and the second cylinder 32, for example, hydraulic, pneumatic, or electric cylinders can be used. Further, instead of the first cylinder 31 and the second cylinder 32, for example, an electric jack may be used.

In this embodiment, heaters 51 and 52 for heating the test piece TP in the container 10 are provided. The heater 51 is provided inside the upper container 11. The heater 52 is provided inside the lower container 12. The heaters 51 and 52 only need to be able to heat the test piece TP in the container 10, and the arrangement position and the number of arrangements thereof may be appropriately changed. For example, the heater 51 may be installed on the side surface of the upper container 11 and the heater 52 may be installed on the side surface of the lower container 12.

The first pressurizing unit 21 is provided with a first upper load sensor 41. The first upper load sensor 41 is a sensor for measuring the load applied to the test piece TP in the container 10 by the first pressurizing unit 21.

A first lower load sensor 42 is provided on the contact member 21b. The first lower load sensor 42 is a sensor for measuring a load (reaction force) applied to the lower container 12 from the guide 60 side.

A second load sensor 43 is provided in the second pressure unit 22. The second load sensor 43 is a sensor for measuring the load applied to the test piece TP in the lower container 12 by the second pressurizing unit 22.

The first upper load sensor 41, the first lower load sensor 42, and the second load sensor 43 output an electric signal according to the magnitude of the measured load to a controller (not shown). As the first upper load sensor 41, the first lower load sensor 42, and the second load sensor 43, a piezoelectric element type, strain gauge type, or capacitance type load cell can be used.

The shear displacement sensor 44 is provided near the side surface of the lower container 12, and is a sensor that measures the shear displacement amount of the test piece TP in the lower container 12 to which a load is applied in the lateral direction by the second pressure unit 22. .. Although not shown, a vertical displacement sensor that measures the amount of vertical displacement of the test piece TP in the lower container 12 is provided near the side surface of the lower container 12.

By using the shear displacement sensor 44, the shear displacement amount of the test piece TP in the lower container 12 can be continuously measured. Further, by using the vertical displacement sensor, the vertical displacement amount of the test piece TP in the lower container 12 can be continuously measured. A laser displacement meter, for example, can be used as the shear displacement sensor 44 and the vertical displacement sensor.

[Parameter acquisition method]
Next, a method of acquiring the parameters to be input to the sand type numerical analysis (FEM analysis) using the above-mentioned one-sided shear test apparatus 1 will be described with reference to FIGS.

(Preconditions for sand mold)
First, in the present embodiment, it is assumed that the sand mold follows the strength envelope of Mohr-Coulomb shown in FIG. 2. The Mohr-Coulomb intensity envelope is shown in equation (1) below.

τ=c+σtanφ...Equation (1)
Here, τ represents shear stress, c represents adhesive force, σ represents normal stress, and φ represents internal friction angle. In designing sand molds (soil and sand), it is important to find the shear strength of sand molds. The Mohr-Coulomb strength envelope is used to determine the shear strength. The Mohr-Coulomb strength envelope is created by matching the Mohr's stress circle with the Coulomb failure criterion. This strength envelope shows the stress state at the fracture surface where the sand mold breaks when a shear stress is applied to the sand mold. That is, when the shear stress τ acting on the sand mold is τ>c+σtanφ, the sand mold is in a broken state. On the other hand, when τ<c+σtanφ, the sand mold is in a stable state.

Further, the sand mold has shearing characteristics as shown in FIG. That is, in the closely packed sand mold, when a shear stress is applied, one sand particle rides on another sand particle and the sand mold expands. Therefore, the vertical displacement amount (volume strain) of sand increases as the shear displacement amount (shear strain) increases. The angle of expansion of this sand mold is indicated by the expansion angle ψ. On the other hand, in the loosely packed sand mold, when a shear stress is applied, the sand particles fall and shrink. Therefore, the vertical displacement of sand decreases as the shear displacement increases.

In the present embodiment, it is premised that the sand mold has the above-mentioned characteristics, and various parameters used for numerical analysis of the sand mold are acquired in the order of the steps shown in FIG. That is, as shown in FIG. 4, parameters are acquired in the order of the setting step (S1), the testing step (S2), and the parameter calculating step (S3). Hereinafter, each step will be described in detail.

(Setting step S1)
In the setting step S1, the conditions for setting the temperature of the sand mold and the physical property values of the sand mold are determined. The physical properties of the sand mold include the type of sand mold, density, water content, activated clay content, compactability, and sand mold strength. Specifically, in the setting step S1, the setting conditions such as the physical property value of the sand mold and the temperature were determined as follows. The sand mold type is silica sand, and the sand mold has physical properties of density 1.53 g/cm ³ , moisture 3.2%, activated clay 7.6 wt%, compactability 38%, sand mold strength 20 N/cm ² It was used as a piece TP.

As the sand-shaped test piece TP, a cylindrical test piece having a diameter of 50 mm and a height of 50 mm was used. The preset temperature of the sand mold was from room temperature to 400°C. Further, the magnitude of the load applied from the first pressurizing unit 21 in the axial direction was set to 0.5 MPa, 0.75 MPa, and 1.0 MPa. In addition, the shear variable of the test piece TP in the lower container 12 due to pressurizing the lower container 12 from the side surface direction by the second pressing unit 22 was set to 10 mm. The shear displacement rate was 1.0 mm/min.

(Test process S2)
Next, in the test step S2, under the plural conditions from the room temperature to a high temperature of 400° C. under the setting conditions determined in the setting step S1, the single shear test device 1 is used to perform the single shear of the sand mold. Test multiple times. The flow of the one-sided shear test will be described with reference to the flowchart of FIG. The flowchart shown in FIG. 5 is an example, and the present invention is not limited to this flowchart.

In the one-sided shear test performed in the test step S2, first, the sand type test piece TP is housed in the container 10 (S21). Then, the control device (not shown) outputs a control signal to operate the first cylinder 31 and move the first pressurizing unit 21 to the container 10 side. As a result, a predetermined load is applied to the test piece TP in the container 10 in the axial direction (S22).

Next, a shear stress is applied to the test piece TP in the side direction while a load is applied to the test piece TP in the container 10 in the axial direction (S23). Specifically, by outputting a control signal from the control device, the second cylinder 32 is operated to move the second pressurizing unit 22 to the container 10 side. As a result, a load is applied to the test piece TP in the lower container 12 from the side surface direction. As a result, shear stress acts on the test piece TP in the container 10.

Then, the lower container 12 is moved along the guide 60 in the lateral direction (leftward direction in FIG. 1) by a predetermined distance, so that the test piece TP in the lower container 12 is sheared by a predetermined distance (S24). In this way, the direct shear test is performed a plurality of times under the setting conditions determined in the setting step S1.

In addition, during the above-mentioned sand type one-sided shear test, the shear displacement amount and the vertical displacement amount of the test piece TP in the lower container 12 are continuously measured by the shear displacement sensor 44 and the vertical displacement sensor. In addition, the load applied to the test piece TP from the first pressurizing unit 21 is continuously measured by the first upper load sensor 41, and the lower container 12 from the guide 60 side is measured by the first lower load sensor 42. The load (reaction force) applied to is continuously measured. Further, the second load sensor 43 continuously measures the shear stress applied to the second pressurizing unit 22 and generated in the test piece TP.

(Parameter calculation step S3)
Next, the parameter calculation step S3 will be described. In the parameter calculation step S3, each parameter is calculated by creating a strength envelope described below for each of a plurality of temperatures based on the measurement result obtained in the test step S2.

Some of the measurement results of the above-mentioned one-sided shear test are shown in FIGS. 6 and 7. FIG. 6 is a graph showing the relationship between the shear displacement amount by the one-sided shear test and the stress measured by the load sensor. FIG. 7 is a graph showing the relationship between the shear displacement amount and the vertical displacement amount according to the one-sided shear test.

In the example shown in FIG. 6, the shear displacement amount is 10 mm, the axial load (upper axial load) by the first pressurizing unit 21 is 0.75 MPa, and the lower portion from the guide 60 side via the contact member 21b. The one-sided shear test was performed under the condition that the load (lower axial load) applied to the container 12 was 0.4 MPa. At this time, the measurement result of the shear stress τ generated in the test piece TP in the lower container 12 was about 0.3 MPa as shown in FIG.

<Calculation of adhesive force c and internal friction angle φ>
The upper axial load obtained from the measurement result in the test step S2 becomes the vertical stress σ applied to the test piece TP in the lower container 12. The vertical stress σ and the shear stress τ are plotted as shown in FIG.

Hereinafter, the same one-sided shear test is performed by changing the load (upper shaft load) from the axial direction applied by the first pressurizing unit 21. If the plots can be made at least at three or more locations, the intensity envelope shown in FIG. 8 can be created. FIG. 8 shows an example of plotting at nine locations.

In this way, by plotting the normal stress σ and the shear stress τ obtained based on the measurement result of the one-sided shear test, the Mohr-Coulomb strength envelope shown in the above formula (1) is created. be able to.

As shown in FIG. 8, if the Mohr-Coulomb strength envelope can be created, the adhesive force c can be calculated from the intercept of the strength envelope, and the internal friction angle φ can be calculated from the slope of the strength envelope. Furthermore, by creating the strength envelope, the non-measurement portion can be complemented from the measurement result obtained in the test step S2, and each parameter can be efficiently calculated.

Then, in the setting step S1, the set temperature of the sand mold is changed from room temperature to 400° C., and the direct shear test is performed a plurality of times in the test step S2, so that the adhesive force c under a plurality of temperatures in the parameter calculation step S3. , And the internal friction angle φ can be calculated.

<Calculation of expansion angle ψ>
Next, the expansion angle ψ is calculated from the relationship between the shear displacement amount and the vertical displacement amount shown in FIG. 7. Specifically, the expansion angle ψ is calculated by, for example, obtaining the inclination of the vertical displacement at a shear displacement amount of 5 mm where the strength envelope is stable. However, when the expansion angle ψ has a negative value, the expansion angle ψ may be set to 0 as a parameter used in the numerical analysis.

Then, in the setting step S1, the set temperature of the sand mold is changed from room temperature to 400° C., and the direct shear test is performed a plurality of times in the test step S2, so that the expansion angle ψ under a plurality of temperatures in the parameter calculation step S3. Can be calculated.

(Results of numerical analysis)
Next, the results of performing a sand-type numerical analysis (FEM analysis) by inputting various parameters obtained by the above-described parameter acquisition method will be described with reference to FIG. 9. By the above-described parameter acquisition method, the sand mold adhesive force c, the sand mold internal friction angle φ, and the sand mold expansion angle ψ are calculated for each of a plurality of different temperatures including a high temperature of 100° C. or higher. FIG. 9 shows an example of an analysis result obtained by inputting each of these parameters and performing a sand type numerical analysis (FEM analysis). As shown in FIG. 9, when the numerical analysis was performed using the parameters acquired by the present embodiment, the analysis value of the numerical analysis regarding the shrinkage amount of the sand mold casting was set to the experimental value even at a high temperature of 100° C. or higher. I was able to get close to it.

[Effect of Embodiment]
According to the above-described parameter acquisition method of the present embodiment, the single shear test is performed on the sand-shaped test piece TP housed in the vertically divisible container 10 at a plurality of temperatures in the test step S2. .. Based on this measurement result, in the parameter calculation step S3, by creating a Mohr-Coulomb strength envelope for each of a plurality of temperatures, each parameter required for a numerical analysis (FEM analysis) for each of a plurality of temperatures. Can be obtained efficiently. With this, in the numerical analysis on the one-sided shear of the sand mold, it is possible to input the above-mentioned parameters and perform a good numerical analysis under a plurality of temperatures, and to determine the shrinkage amount of the casting and the sand mold reaction force during the solidification shrinkage of the sand mold. It can be predicted with high accuracy.

Further, according to the above-mentioned parameter acquisition method, the parameter calculation step is performed based on the measurement results of the sand mold shear stress τ, the sand mold vertical stress σ, and the vertical displacement amount under a plurality of temperatures obtained in the test step S2. In S3, the adhesive force c of the sand mold for each temperature, the internal friction angle φ of the sand mold, and the expansion angle ψ of the sand mold can be calculated. As a result, the adhesive force c of the sand mold for each temperature, the internal friction angle φ, and the expansion angle ψ can be input as parameters to the numerical analysis regarding the one-sided shear of the sand mold, and good numerical analysis results can be obtained.

Further, according to the above-mentioned parameter acquisition method, it is possible to acquire the parameters used for the numerical analysis of the direct shear of the sand mold at a high temperature of 100° C. or higher, so that the numerical analysis of the direct shear of the sand mold at a high temperature can be well performed. It becomes possible to predict the shear strength of the sand mold under high temperature with high accuracy.

In addition, according to the above-described parameter acquisition method, based on the measurement result obtained in the test step S2, the range not measured in the test step S2 (non-measurement portion) is complemented, and the strength of Mohr-Coulomb is obtained. Create an envelope. As a result, the number of direct shear tests required to acquire each parameter used for numerical analysis can be reduced, and each parameter can be acquired efficiently.

According to the above-mentioned sand-type single-sided shear test apparatus 1, the first pressurizing section 21 applies a load to the test piece TP in the container 10 from the axial direction, and the second pressurizing section 22 moves the test piece TP up and down. By applying a load to the test piece TP in the lower container 12 on one side of the divided container 10 from the side direction, a desired shear stress can be applied to the test piece TP to perform the sand-type one-sided shear test. it can. Thereby, by using the measurement result of the one-sided shear test, it becomes possible to obtain accurate values of the adhesive force c, the internal friction angle φ, and the expansion angle ψ in the Mohr-Coulomb equation (1). ..

In particular, since the test piece TP in the container 10 can be heated to a high temperature of at least 100° C. or more by the heaters 51 and 52, the sand mold single-side shear test can be performed at a high temperature. Thereby, it is possible to measure the shear stress and the shear displacement amount generated during the direct shearing of the sand mold under a plurality of temperatures including the high temperature.

The present invention is not limited to each of the above-described embodiments, and various modifications can be made within the scope of the claims, and an implementation obtained by appropriately combining the technical means disclosed in each of the different embodiments. The form is also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Single shear test apparatus 10 Container 11 Upper container 12 Lower container 21 1st pressurizing part 22 2nd pressurizing part 41 1st upper load sensor (1st load sensor)
42 First Lower Load Sensor (First Load Sensor)
43 Second load sensor 44 Shear displacement sensor 51, 52 Heater TP test piece S1 setting step S2 test step S3 Parameter calculation step

Claims (5)

A method for obtaining parameters used for numerical analysis of sand type one-sided shear,
A setting step for determining setting conditions including the temperature and physical property value of the sand mold;
Using the setting conditions determined by the setting step, under a plurality of temperatures, a test step of performing a one-sided shear test on the sand-shaped test piece housed in a vertically divisible container,
As the sand mold follows a predetermined strength envelope, by creating the strength envelope for each of a plurality of temperatures based on the measurement results obtained by the test step, a parameter calculation step of calculating the parameter,
A method for obtaining a parameter, comprising: The setting conditions determined in the setting step include the magnitude of the load applied to the sand mold from the axial direction, and the shear displacement amount of the sand mold,
The measurement results obtained in the test step include shear stress of the sand mold under a plurality of temperatures, vertical stress of the sand mold, and vertical displacement amount,
The parameter calculated in the parameter calculation step includes an adhesive force of the sand mold for each temperature, an internal friction angle of the sand mold, and an expansion angle of the sand mold. How to get the parameters. The method for acquiring parameters according to claim 1 or 2, wherein the temperature of the sand mold under the set conditions includes a high temperature of at least 100°C or higher. 4. The intensity envelope created in the parameter calculating step is created by complementing a non-measured portion from the measurement result obtained in the testing step. How to get the parameters described in. A sand type single-sided shear tester,
An accommodating container that can be divided into upper and lower parts for accommodating the sand-type test piece,
A heater for heating the test piece in the container,
A first pressurizing section for applying a load to the test piece in the container from a first direction;
A second application of applying a load from a second direction orthogonal to the first direction to the test piece in one of the vertically divided one side of the container with the load applied to the first pressurizing unit. Pressure section,
A first load sensor for measuring a load applied to the test piece by the first pressurizing unit;
A second load sensor for measuring a shear stress generated in the test piece to which a load is applied by the second pressurizing unit;
A shear displacement sensor that measures a shear displacement amount of the test piece to which a load is applied by the second pressurizing unit;
A sand-type single-sided shear tester characterized by being equipped with.

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