Applied Mechanics and Materials Vol. 684

Abstract: In disaster rescue vehicles use ANSYS finite element analysis software, establishes the finite element calculation model for car key components, the static stress and strain analysis, get key components under different conditions of displacement and stress distribution nephogram, find out the bearing connection support frame and dangerous parts of the suspension control arm The bearing connection support frame and suspension control arm for modal analysis, get the bearing connection support frame and suspension control arm each order natural frequencies and natural modes, avoiding resonance and increase the weighing accuracy calculation and analysis for automobile bearing connection support frame and suspension control arm provides reference basis for the retrofit design.

Abstract: To sail and work safely in different working conditions, the ballast system of a certain crane vessel is researched and designed because it’s strict with hull stability. According to the characteristic of the vessel arrangement, the concept of ring pipe type is adopted in the ballast system. The dual and single ring types of ballast system are designed, analyzed and comprised with each other respectively. Simultaneously, the normal materials of ballast system are analyzed, and the suitable material is selected.

Abstract: Tooling system for high-speed machining is one of the key components of high-end CNC machine , its stability and reliability directly affects the quality and performance of the machine. Based on the finite element method, developing a 3D finite model of high-speed machining tool system, studying on the stability of the high Speed machining tool from the natural frequency by the method of modal analysis. Analysis the amount of the overhang and clamping of the tooling , different shank taper interference fit and under different speed conditions, which affects the natural frequency of high-speed machining tool system. Proposed to the approach of improving system stability, which also provides a theoretical basis for the development of new high-speed machining tool system.

Abstract: In this paper, control system of rotary inverted pendulum based on ARM is designed, which is composed by mechanical section and control section. The system measures signal for variation of angle of radial arm and pendulum rod and transmits such signal to ARM control panel, after which control rate can be calculated through PID control algorithm. Inversion of pendulum rod can be controlled through rotation of the radial arm on a plane driven by an electric motor, and the pendulum rod can rotate on a vertical plane. Finally, MATLAB is used to conduct simulation for three parameters including proportionality coefficient (K_P), integral coefficient (K_I) and differential coefficient (K_D), based on which ideal parameters are determined, stable control of pendulum rod inversion near equilibrium point is realized, and feasibility of control algorithm is verified.

Abstract: This study investigated the effect of fixation screw number of intramedullary nail on the postoperative stability of the femoral construct in treatment of periprosthetic fractures after total knee arthroplasty. With use of a material testing machine, both compressive and torsion tests were conducted to evaluate the biomechanical behavior of intact, and femora with periprosthetic fractures treated with retrograde intramedullary nail with 5-screw and 9-screw fixations. The results indicated the followings: 1) the average compressive stiffness for intact, 5-screw and 9-screw groups were 1,159±61.7, 950.6±18.6 and 958.2±26.1 N/mm, respectively. No statistical difference was found between 5-screw and 9-screw groups (p>0.05). However, significant difference was found between intact/5-screw and intact/9-screw groups (p<0.05). 2). the average torsion stiffness for intact, 5-screw group and 9-screw group were 5,527±71.2, 2,652±35.4 and 2,858±81.7 N*mm/Degree, respectively. Statistical difference was found between each other groups (p<0.05).

Abstract: Vertebroplasty has been widely accepted in treatment of osteoporotic vertebral fractures. Polymerization of bone cement stabilizes the fractured vertebra by increasing its mechanical strength, thereby providing symptomatic pain relief. Many factors affect the reaction of polymerization of polymethylmethacrylate and, therefore, the reaction rate and injection permeability of bone cement. This may increase the probability of a surgeon missing the crucial period, leading to the increase of the risks of uneven cement distribution, cement leakage and premature hardening of cement. Hypothermic manipulation of bone cement is expected to reduce reaction rate and hence, extending the handling time. However, in a manner of reducing the environmental temperature of bone cement, there are still uncertainties on handling time, cement distribution pattern and injection permeability of cement. This study is thus designed to investigate the efficacy of temperature control for enhancing applicability and safety of bone cement.

Abstract: The article focuses on the application of a probabilistic approach to the evaluation of residual stresses in tensometric (strain gauge) hole-drilling methods. The principle of this method is based on the use of a strain gauge rosette on the surface of the tested component and the subsequent drilling of a hole in the centre of this rosette. This disturbs the internal force and moment equilibrium, which in turn causes surface deformations that are measured by the rosette. The measured deformations are then evaluated, and derived theories are applied to determine the course and magnitude of residual stresses taking into account the random character of the input parameters using the SBRA (Simulation-Based Reliability Assessment) method, which proves to be highly practical. The probabilistic approach to determining residual stresses is a new, original approach which brings a suitable and accurate description of the variance in measured values.

Abstract: The solution of the interaction between a structure and its foundation is an important problem in mechanics and technical applications. This paper presents a solution of a circular plate rested on an elastic (Winkler) foundation. A jig was created for the purpose of loading a circular plate with a specific bending moment and force on the plate circumference. Laboratory testing was performed to determine the deflection in the centre and at the edge of the plate. Measurement apparatus was assembled and measurements were carried out; the results of the measurement were compared with the analytical solutions and FEM results. On the basis of these comparisons, the foundation modulus was determined. The experiment, analytical solution and FEM give similar results, thus providing a solid basis for technical applications.

Abstract: This article focuses on the biomechanical evaluation of the interaction between load forces to which a sitting man and the seat are mutually exposed. The load forces, which consider actual dispersion in the human population through histograms, are determined using a probabilistic method known as the Simulation-Based Reliability Assessment (SBRA). A simple flat model shows a basic and high-quality stochastic evaluation of all the forces that affect the man and the seat. The results and methodology can be used in many areas of biomechanics, ergonomics or industrial design.