Applied Mechanics and Materials Vols. 477-478

Abstract: The upper bound on the energy norm of solutions is a necessary condition in the present verification methods of the displacement-based finite element method. In this paper, we give a brief review of the existing methods for the upper bounds on the energy norm of solutions. Compared with other verification methods, the energy relaxation method does not require solving a series of sub-problems, but only solving a global problem, that is beneficial to its application and implementation in the verification of nonlinear finite element analysis.

Abstract: Tripod is the key components of snubbing unit, its strength directly affect the normal work of snubbing unit. Considering the structure and force characteristics of key components tripod of snubbing unit, three-dimensional finite element analysis model of tripod is established. By using the finite element method, mechanical analysis of tripod is conducted and safety evaluation is finished by adopting the stress classification and introducing analysis design standard of pressure vessel. The results show that key components tripod of snubbing unit are safe and reliable under the maximum lifting force and the maximum downward force. It provides theory evidence for snubbing unit design. The safety evaluation method provides effective evaluation methods for complex structure strength evaluation.

Abstract: The luffing system of giant jib crane is usually consisted of rigid bars and flexible cables, and the weight of components causes sagging deformation and large displacement. In order to study the nonlinear method for multi-bar luffing system of giant jib crane, this paper completed theoretical analysis and example verification. Based on catenary theory, the equation of luffing strand was obtained. Spatial multi-bar equation of three bars was proposed and it was extended to any more bars. Then, equilibrium equations of components were written in sequence, and the equations of multi-bar luffing system were established with the elastic deformation of multi-bar and luffing strand. Finally, by taking the 2500-ton ring crane as an example, the results demonstrated that: the nonlinearity of combined multi-bar luffing system negatively influences the structural behavior, and the results calculated by the proved nonlinear method is more reasonable and closer to the actuality than the linear method, so it provides theoretical basis for engineering design and construction.

Abstract: Established the mathematical model of hoisting mechanism based on the theory of vibration, through experimental and theoretical method obtained system stiffness coefficient, damping coefficient, finally calculated reel resistance torque. According to the mathematical model, the hoisting mechanism is simulated and analyzed by using virtual prototype technology, it provide a theoretical basis for design of non-contact type weighing sensor.

Abstract: Based on DEFORM finite element software, the model of turning process of GMA was built, and the relation function among turning speed, turning depth and turning force of GMA turning system was achieved. Then, considering the turning force model, the dynamic equation of the turning system was established and the time domain and frequency domain of GMA turning system were discussed with different corresponding parameters. Results show that turning speed and turning depth have apparent effects on turning force of GMA turning system. Therefore, it is necessary to take the impact into consideration when analyzing dynamic characteristics of the turning system.

Abstract: Since slamming loads on connecting bridges of trimaran is very important for the structural design. In this paper, trimaran slamming load calculation method is studied. First added mass caused by typical hull section and wet-deck slamming are investigated, then wet-deck slamming peak pressure are gotten by modified flat slamming theory with considered of the effect of air cushion, the regression equation of which is given by statistical process. Finally, the time-spatial distribution of slamming pressure along the wet-deck is given. This method can provide a reference for the preliminary design and operation of trimaran.

Abstract: Red blood cell (RBC) particle detection and counting with characteristics in blood cell systems has been done by computer simulation. A simulation region, including plasma, red blood cells (RBCs) and platelets, was modeled by an assembly of discrete particles. The proposed method has detected the red particle from blood cell systems through different simulations of MATLAB and GAMBIT & FLUENT. After the detection, the number of red particles in a sampled cell has been counted and the characteristics about the red particles for analyzing the Birth-Death growth of each red particle have been found.

Abstract: With methods of ISOMED isokinetic muscle testing system and live observation on Olympic preparation and mathematical statistics, this paper tries to measure and analyze the characteristics of elite female speed skaters knee and hip flexor-extensor muscle strength and training content, period and load for the whole year. The main conclusions are as follows: 1. Features of the skaters knee and hip muscle strength are fit in with the sport biomechanical law, and their fast strength and greatest strength are higher than those of female athletes in other national events. In high speed area, the strength of female athletes even achieves the same level of male ones. 2. The equilibrium and coordination of flexor-extensor and same name muscle group have both reached a high level, but they are lower than international recommended values. 3. The training load of strength throughout the year peaks at the whole phases of preparation 1and preparation 2, the early stages of competition 1 and preparation 3. The load of short distance athletes is larger than that of long distance athletes, but the general trend of both is same. 4. National elite female skaters excise more than before in small muscle group, greatest strength in high speed, continuous speed strength and strength endurance. 5. Based on a comparative analysis of the testing results between these skaters and other athletes, the training arrangement can meet the strength requirements of specific training and can also be the reference of training for other athletes.

Abstract: With the method of ISOMED isokinetic testing system, INBODY 3.0 body composition analyzer and ADIPOMETER subcutaneous fat measuring instrument, this study tries to measure the fitness characteristics of female athletes and then apply mathematical statistics to complete a regression analysis with their results. The main conclusions are as follows: 1. 480°/s hip extensor480°/s knee extensor and 240°/s radios of knee flexor-extensor are highly negative correlated with 500m results, and the regression equation is y = 20.496 - 0.72x1 - 0.64x2 - 0.82x3. 2. Results of the body composition and subcutaneous fat are not highly correlated with 500m result. The hip flexor and extensor at three angular speeds are highly negative correlated with subcutaneous fat of abdomen, upper knee and back, but are highly positive correlated with weight, FFM, BMI and BMR. 3. According to the testing results of body composition, there is no significant difference between two groups, both up to the standard of Asia and world. The maximum value of subcutaneous fat is in abdomen and for another is in upper knees. The minimum value of subcutaneous fat is in outer thigh for long distance athletes and in back for short distance athletes, no significant difference.

Abstract: The objective of the present study was to study the effect of seat angle change on body pressure distribution. The body pressure distribution and body subjective comfort evaluation were recorded in five angles of wheelchair seat surface(0 °, 3 °, 6 °, 9 °and 12 °) by using X-Sensor system. 20 healthy volunteers (10 males and 10 females) were tested to obtain the average pressure of back, the maximum pressure of back, the contact area of back, the average pressure of buttock, the maximum pressure of buttock, the contact area of buttock. The experimental data were analyzed by statistical analysis software SPSS 19.0 and MATLAB. Finally the comfort indicator of wheelchair was determined based on body pressure distribution, and the more comfortable angle of wheelchair seat surface was also obtained, which was 3.17°. The study should provide a strong help for the comfortable wheelchair designing.