A novel meshless deformation model of biological soft tissue, which is mainly based on the radial basis function point interpolation, is presented for interactive simulation applications such as virtual surgery simulators. Compared with conventional mesh models, the proposed model is particularly suitable for simulating large deformation, sucking and cutting tasks since there is no need to maintain grid information. Kelvin viscoelasticity, which represents relaxation, creep, and hysteresis of soft tissue, is integrated into the proposed model, making the simulation much more realistic than many existing meshless models. To verify the validity of the proposed model, a biomechanical test was performed on real-life biological tissue and the results show that the maximum relative error between the forces from the biomechanical test and those obtained from the model is less than 5.8%. The proposed model was also implemented on a neurosurgery simulator, which showed that the deformation of the brain tumor can be simulated in a high degree of accuracy with real-time performance. In particular, the error and distortion from the remeshing process inherited in conventional mesh models when deformation is large are avoided.

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Backfilling mining method is an overlying strata control way, which is widely used in underground coal mine. This method is effective in preventing and controlling geological disasters such as surface subsidence, mine water inrush, rock burst, and other disasters. Cement-treated marine clay (CMC) is a typical porous media, which has abundant reserves and can be used as a new backfilling material. Therefore, the mechanical characteristics of CMC are very important for overlying strata control in coal mine. To investigate stress-strain behavior of CMC, isotropic consolidated drained (CID) triaxial test and isotropic compression test (ICT) were conducted with different confining pressures in the range of 50–800 kPa. Stress-strain behavior was found similar to those of the overconsolidated stress-strain behavior as well as the pore water pressure versus strain. Stress versus strain curves under lower confining pressure 50–250 kPa presented shear dilatancy. The result shows that the peak strength increased linearly with increasing confining pressure. The internal friction angle and cohesion are 48° and 590 kPa, respectively. Before the confining pressure reaches 727 kPa, which is the primary yielding point, the secant modulus E1 (the secant modulus at 1% axial strain) and the secant modulus E50 (corresponding to the 50% of the peak point) increase initially and decrease afterwards with the increasing of confining pressure. Afterwards, the two parameters increased with increasing confining pressure. The yielding stress occurred in the stage, generating a dramatic decrease in tangent modulus. This study can be a theoretical basis for engineering application of this new backfilling material.

High-precision 3D topography measurement is essential to ensure quality and performance of shaft parts. Generally, the main difficulty of measuring rotary objects on a turntable is the low accuracy of axis calibration. To solve this problem, this study introduces two methods for calibrating the rotation axis of the turntable and proposes a method for reconstructing the 3D shape of the object by converting the rotation axis parameters of the binocular vision. A calibration camera is used to shoot a 2D checkerboard calibration board against the rotating table, and the calibration process of a high-precision space rotation axis is developed and implemented. This laser vision measurement system consists of a calibration camera, a measurement camera, and a rotation system. This system can realize reconstruction of the 3D shape of the object in accordance with the rotation axis parameters in any position. The experiment on measuring standard parts verifies the effectiveness of the algorithm. It provides a new idea for the measurement of rotary object shapes.