The contact and non-contact behaviors of material interfaces generate harmonics arising from interactions with large amplitude incident waves. In this phenomenon, which is called contact acoustic nonlinearity (CAN), intermittent impacts by an incident wave cause the interface contact phase to alternate between contact and separation. This paper proposes a method for numerical simulation of CAN using an elastodynamic finite integration technique (EFIT). The accuracy of the EFIT simulation was verified through comparison with an analytical solution. In one-dimensional CAN theory, a wave penetrating at an interface demonstrates a sawtooth waveform indicating that the interface is closing with a constant velocity. Simulation results revealed that the closing velocity is determined by the compressive stress of the material, and experimental measurements on a polymethylmethacrylate specimen revealed the harmonics caused by the sawtooth wave.

This paper deals with finite element analysis involving tens of billions of degrees of freedom (DOF) in a high-frequency electromagnetic field. The iterative substructuring method has been considered to be an efficient parallel computing method. To show the possibility of analyzing electromagnetic field problems with complex numbers and tens of billions of DOF, problems with up to 30 billion DOF are analyzed by all nodes of an Oakleaf-FX supercomputer. As a result, the human model has been successfully solved in approximately 10 minutes, and the simple hyperthermia applicator model with 30 billion DOF has been successfully solved in approximately 19 minutes. There is a problem in the output analysis results, and bugs relating to the limits of the 32-bit integer data type have been found and fixed through actual analysis of problems with tens of billions of DOF.

The practical use of the fluid-structure interactions (FSI) analysis system requires the robustness for the parametric design of artifacts. In the FSI analysis employing interface tracking methods, mesh moving technique is significant for avoiding the failure of the analysis due to the mesh distortion. Although many conventional techniques have been introduced in the system, there still remain some cases where the analysis fails because of the mesh distortion. For the further improvement of the robustness, we propose a new mesh moving technique, minimum-height-based stiffening technique, where the mesh deformation of the fluid domain is virtually governed by the linear elastic equations and the stiffness of each element is determined according to its minimum height. The proposed technique is applied to two-dimensional benchmark problems with three types of prescribed motions or deformation: translation, rotation, and bending. The results were compared with those with Jacobian-based-stiffening technique, which is one of the most effective approaches, in terms of mesh quality factors. As a result, the proposed technique shows better performance, i.e. the improvement by more than 10% for our mesh quality factor. In addition, low sensitivity of the mesh quality factors to the optimum value of the control parameter was observed. This low sensitivity can contributes to the usability of our proposed technique.

Level-set approach extended for its diffusive solution is investigated to make a relation to conservation law of fluid phenomena and phase field approach based on the free energy theory. Considering mathematical analysis of level-set approach and re-initialization procedure, a new mathematical model of fluid interface is introduced defined by a cumulated layer of multiple contour elements. A generalized formulation of the extended level-set equation is derived by using phase field approach with a potential function model newly proposed for non-equilibrium solution of the local contour elements.

According to popularization of the driver assist system and future spread of the autonomous vehicle, the importance of the HMI between the system and the driver is increased. We study the HMI which does not obstruct the driving about the command from the driver to the system among the communication between the system and the driver. As the hardware for it, the application of the tablet terminal of which the popularization is remarkable in the daily life is considered. By using the tablet terminal to be helpful in our daily, it also may be possible to attempt the fusion of the daily data and the driving data. There are, however, few application studies of the HMI using the tablet terminal for an automobile. Therefore, the capability of the tablet terminal applying to the in-vehicle HMI is explored by the experiment with the driving simulator and the possibility is found out in this paper.

Robots have been developed that can do precise work, repeat the same job indefinitely, and even replace humans by faithfully reproducing human movements and the human form. However, we decided on a methodology that overturns that image of perfection and precision by using a robot that is unable to move as well as humans. In this study, we examined the use of such a robot to cultivate a caring mindset, or the desire to help others, in young children. A small-scale, remotely operable robot that stood at children's eye-level was manufactured. The robot was brought to a preschool and presented to the children, and an experiment was conducted by having the children exposed to this "disabled" robot that had trouble performing simple tasks, such as opening and closing doors. In this experiment, indications of how the children would accept the robot, and whether they would help the robot, were observed. The results show that children younger than 19 months were afraid of the robot and would not accept it, but children older than ages approximately one to two years old accepted the robot and were observed attempting to help it, confirming that the use of robots can contribute to the cultivation of a caring mindset.

In almost all Space Solar Power Systems (SSPS) concepts proposed in the world, constructing large space structures of several hundred meters or more is necessary. On the other hand, a largest space structure realized by traditional hand made construction methods is the International Space Station (ISS). However, the problem is that this construction method is dangerous, expensive and time-consuming. Therefore, an automatic construction method for large space structures is required to solve the problems. In this paper, we propose a construction method for the 100-m-class plate structure composed of many panels toward the realization of the SSPS. The advantages of this method are that very difficult technologies are not required and it is a concrete method. From the result of the ground experiments, we showed that the basic functions of a truss deployment machine in the proposed construction method is feasible.

While there exist many works on the inverse analysis of the residual stress which use the inherent strain or the body force as a stress source, the authors have proposed a body force dipole (BFD) as the source, since it could simulate fairly well shearing deformation and set no limit to a shape of a BFD distributing area. Some sort of regularization is needed to obtain a reasonable BFD solution, when perturbed stresses are used in the inverse analysis as data measured on a surface of a body. The singular value decomposition (SVD) is used for deriving the BFD solution in the present study. There, artificial noise α is taken into account as a regularization parameter to reduce the sensitivity of the computed solution to the perturbation of the stress data. A good artificial noise α is chosen based on the L-curve, the plot of the solution norm versus the norm of the stress residual vector. Numerical results for an analytical model demonstrate that the regularization method used in the present work is very effective for deriving the BFD solution which is not too sensitive to the perturbation of the stress and has a suitably small norm. Also, effects of additional displacement data on the solution is discussed, which are excessively defined as boundary conditions so as to guarantee the uniqueness of the residual stress. Numerical results show that the additional displacements and their perturbations have influence on the regularized solution almost nil. And a theoretical examination reveals that a submatrix for the displacement hardly contributes to the eigenvalues, the squares of the singular values of a sensitivity matrix, so that the displacements have little effect on the solution for the present case.

Using equilibrium molecular dynamics (EMD), we analyzed the friction between water-methanol liquid mixtures and a non-polar solid wall. Specifically, we calculated the friction coefficient (FC) from the autocorrelation of the shear force exerted on a liquid from a solid wall using two Green-Kubo (GK) equations proposed by Bocquet and Barrat (BB) [Physical Review E, Vol. 49, (1994), 3079], and Huang and Szulfarska (HS) [Physical Review E, Vol. 89 (2014), 032119], and compared these FC values with those obtained in our previous non-equilibrium molecular dynamics (NEMD) work. Both GK equations reproduced the FC dependence on the methanol concentration in the first adsorption layer X_a^MeOH observed with NEMD, but the BB method gave a better estimate of the NEMD results with a difference of 20 % at largest. The independent molecular FCs of water and methanol, which were only extractable with the HS method from EMD simulations, corresponded qualitatively well with the NEMD results regarding the dependency on X_a^MeOH. Though certain discrepancies were observed between the EMD and NEMD results, the EMD had a considerable advantage regarding the computational time required to calculate the FC with a comparable error: the EMD computational time was about 20 times shorter than the NEMD time in the present system.

Robotic welding has been the biggest use in many industry. It is important to control weld robots without weld spatter for small size target. To prevent flying weld spatter, the precursory phenomenon of weld spatter must be detected, and power source of robotic welding must be controlled to reduce before weld spatter occurs. This study aimed to propose a control system to prevent the occurrence of flying weld spatter during laser or gas tungsten arc (GTA) welding process in real-time. Because the strategy involves detecting the precursory phenomenon at high-speed, we simplified the recognition system as much as possible. The system consists of a lighting system to illuminate the weld pool, a high-speed camera and an FPGA board. The control algorithm of this system used image data information for a histogram. We analyzed the images from the high-speed camera during welding. Our analysis found that, just before the weld spatter is generated, very bright pixels temporarily and abnormally increased as the precursory phenomenon. According to the proposed system, it is possible to prevent the occurrence of weld spattering in real time during the welding process. This integration of visual feedback in a robotic welding system enhances the quality of the weld work.

The exact formulation of the multiplicative hyperelastic-based plastic constitutive equation is given for the conventional elastoplastic constitutive equation with the yield surface enclosing the purely-elastic domain undergoing the isotropic and the kinematic hardenings in this article. The generalized flow rules for the plastic strain rate and the rate of kinematic hardening variable and their related plastic spins are incorporated in this formulation.

A compliant mechanism is a structure designed to be flexible in order to achieve a specified motion as a mechanism. Such mechanisms can enable a variety of functions. In particular, the operation of highly sensitive sensors and actuators in industrial applications often requires reliable and flexible displacement magnification mechanisms. It is well known that topology optimization offers a useful and powerful method for compliant mechanism design, where displacement in a targeted direction at an output port is to be maximized based on the use of artificial spring components located at the boundaries of the input and output ports. However, such spring components are not always a fundamental requirement. This letter presents a formulation for a compliant displacement magnification mechanism design based on the concept of effective energy. Several numerical examples are provided to confirm the utility of the proposed formulation.

Pneumatic anti-vibration apparatus (AVA) has been used for suppression of vibration from floor in the field like semiconductor manufacturing. The compressed air supplied to the pneumatic AVA is generated by the air compressor. During the compression process of the air, the pressure of the compressed air varies. Consequently, the pressure variation changes the flow rate of the air supplied to the pneumatic AVA, which is called flow disturbance. Based on the internal model principle, the suppression of vibration of AVA due to flow disturbance has been confirmed by using Central Pattern Generator (CPG). Previous studies in the field of biology have confirmed the existence of a neuronal network that generates a walking rhythm in the spinal cord of an organism, and this is called CPG. Some researchers have applied CPG to such as walking of biped-robots. However, there are no applications using information inside CPG. This letter proposes using internal information in CPG as new method for further vibration suppression, compared with the conventional method. Specifically, this method makes use of outputs corresponding to differential and integral signals inside the CPG. It is shown the effectiveness of the proposed method by experimental results.

The cost of preparing analysis and data handling is remarkable compared with the speedup from parallelization. Several studies have reported for a problem solving environment (PSE) or a cloud computer aided engineering (CAE) service. However, few studies have covered part of CAE process. This paper proposes design of cloud CAE platform and development of a web-based all-in-one CAE system. The platform design takes account of applying to large-scale analyses by imaging methods and data structures. Assembling them, we provide cloud CAE services. As numerical examples, we apply the system to some finite element analysis models. We confirmed that this system has ability for CAE work which has a hundred million degrees of freedom.