Abstract: A particle simulation device comprises: a position information acquisition unit that acquires position information for the particles; a pair setting unit that selects pairs of particles and sets a pair number, on the basis of the position information; a reference information generation unit that generates a matrix from the pair numbers and the particle numbers, and generates reference information for referencing the pair numbers from the particle numbers on the basis of a matrix in which the order of the rows of the matrix are sorted on the basis of the particle numbers; a sum calculation unit that calculates a sum of interaction forces for each particle on the basis of the reference information; and a particle information calculation unit that calculates the position and velocity of the particles on the basis of the sum of interaction forces.

Abstract: It is an object to provide a stress history measurement method and a stress sensor by which the stress history of an object being measured can be measured easily with high accuracy over a wide stress measurement range. In the stress history measurement method, the stress history to which the object being measured has been subjected is measured on the basis of the ratio of twinned calcite particles after the object to be measured has been subjected to an external force, the object having a stress sensor embedded therein and capable of being deformed elastically when being subjected to the external force, the sensor including a number of calcite particles. The stress sensor is configured such that a number of calcite particles are hardened by a resin with adjacent particles kept in contact with each other.

Abstract: A particle simulation device comprises: a position information acquisition unit that acquires position information for the particles; a pair setting unit that selects pairs of particles and sets a pair number, on the basis of the position information; a reference information generation unit that generates a matrix from the pair numbers and the particle numbers, and generates reference information for referencing the pair numbers from the particle numbers on the basis of a matrix in which the order of the rows of the matrix are sorted on the basis of the particle numbers; a sum calculation unit that calculates a sum of interaction forces for each particle on the basis of the reference information; and a particle information calculation unit that calculates the position and velocity of the particles on the basis of the sum of interaction forces.

Abstract: It is an object to provide a stress history measurement method and a stress sensor by which the stress history of an object being measured can be measured easily with high accuracy over a vide stress measurement range. In the stress history measurement method, the stress history to which the object being measured has been subjected is measured on the basis of the ratio of twinned calcite particles after the object to be measured has been subjected to an external force, the object having a stress sensor embedded therein and capable of being deformed elastically when being subjected to the external, force, the sensor including a number of calcite particles. The stress sensor is configured such that a number of calcite particles are hardened by a resin with adjacent particles kept in contact with each other.

Abstract: An analysis apparatus 10 is an apparatus for analyzing a motion of a deformable body and comprises a model generation unit 12 for generating a model of the deformable body provided with virtual particles whose centers constitute vertexes of a tetrahedron dividing the deformable body, a first force calculation unit 13 for calculating a first force occurring between the particles nonadjacent to each other provided on a surface of the deformable body, a second force calculation unit 14 for computing a stress occurring in the tetrahedron dividing the deformable body and calculating a second force occurring in each particle from a plane dividing the tetrahedron and the stress, and a particle position updating unit 15 for taking a sum of the first and second forces so as to compute a force occurring in each particle and solving a motion equation so as to update a position of each particle.

Abstract: There are provided a method by which a stress history of an object can be measured with high reliability if the object, which has temporarily been elastically deformed upon receiving an external force, recovers from the elastic deformation, and a composite material containing cement as a main component, of which a stress history can be measured with high reliability without reducing the strength of the material itself and without breaking the structure. To achieve the above-mentioned advantages, the method includes the steps of: acquiring an initial value of a twin density for calcite particles contained in an object to be measured that is elastically deformable upon receiving an external force; and measuring a history of stresses received by the object to be measured on the basis of a difference from the initial value in respect of the twin density for the calcite particles after the object to be measured receives the external force.

Abstract: The objective of the present invention is to provide a method for producing a calcite single crystal which is appropriately fine in a large scale with no difficulty. The method for producing a calcite single crystal according to the present invention is characterized in comprising the steps of mixing raw material calcium carbonate with an ammonium nitrate aqueous solution to obtain a raw material mixed liquid, wherein pH of the ammonium nitrate aqueous solution is not less than 7.0 and not more than 8.0, a concentration of the ammonium nitrate aqueous solution is not less than 2 M, and a concentration of calcium carbonate in the raw material mixed liquid is not less than 4 g/L and not more than 16 g/L; heating the raw material mixed liquid at not less than 125° C.; and then gradually cooling the raw material mixed liquid.

Abstract: The memory size used in DEM calculation of particle having a particle diameter distribution is suppressed.

Abstract: The memory size used in DEM calculation of particle having a particle diameter distribution is suppressed.

Abstract: There are provided a method by which a stress history of an object can be measured with high reliability if the object, which has temporarily been elastically deformed upon receiving an external force, recovers from the elastic deformation, and a composite material containing cement as a main component, of which a stress history can be measured with high reliability without reducing the strength of the material itself and without breaking the structure. To achieve the above-mentioned advantages, the method includes the steps of: acquiring an initial value of a twin density for calcite particles contained in an object to be measured that is elastically deformable upon receiving an external force; and measuring a history of stresses received by the object to be measured on the basis of a difference from the initial value in respect of the twin density for the calcite particles after the object to be measured receives the external force.

Abstract: When an integrated displacement amount of the particles constituting a contact candidate pair is equal to or more than ¼ (one-quarter) cell or more, likelihood becomes high that the particles of the contact candidate particle pair, which was not in contact with each other, would come into contact with each other. Then, in such high likelihood, data relating to contact candidate particle pairs are updated. With this arrangement, even if contact candidate particle pair data updating is decimated and part of contact determination is accordingly omitted to increase a computing speed of the contact determination, accuracy of simulation will not be reduced. Thus, according to the present invention, the computing speed of the contact determination can be increased without lowering the accuracy of simulation.

Abstract: When an integrated displacement amount of the particles constituting a contact candidate pair is equal to or more than ¼ (one-quarter) cell or more, likelihood becomes high that the particles of the contact candidate particle pair, which was not in contact with each other, would come into contact with each other. Then, in such high likelihood, data relating to contact candidate particle pairs are updated. With this arrangement, even if contact candidate particle pair data updating is decimated and part of contact determination is accordingly omitted to increase a computing speed of the contact determination, accuracy of simulation will not be reduced. Thus, according to the present invention, the computing speed of the contact determination can be increased without lowering the accuracy of simulation.