Applied Mechanics and Materials Vols. 716-717

Abstract: According to the characteristics of the general tunnel structure, one type of the concrete spraying machine is designed and researched for convenient operation. Based on the work condition, the structure and dimensions of the mechanical are calculated, including the thickness and section size of each working arm. During the loading situation, the strength and stiffness of the key components are calculated by theoretical arithmetic. The concrete spraying machine structure is simulated for dynamic analysis comparison by Pro/E and Matlab software. The design method of the concrete spraying machine has certain directive significance for advanced product manufacturing.

Abstract: The hybrid bus frame is a vehicle’s main bearing component, in which bearing stress state is very complex. In this article, the virtual prototype vehicle model is established to extract dynamic loads between each key connecting parts and the hybrid bus frame. At the same time, the hybrid bus frame finite element model is established to make strength and stiffness analysis with dynamic loads as boundary conditions. The results verify that the strength and stiffness can meet the hybrid bus frame requirement, and the largest deformation and stress area is found. The results also can provide an important basis for correcting the frame structure. What’s more, this paper makes a comparison between the method of the frame finite element analysis based on dynamic loads and the method of the frame finite element analysis based on the statics, concluded a result that the frame finite element analysis based on dynamic loads can more accurately describe the real stress state of the frame and the analysis result is more reliable.

Abstract: The structural characteristics of the tensioning device in the wire saw manufacturing equipment is introduced. Based on the characteristic of the strainer, the principle of variable universe fuzzy control is adopted to deal with the controlling objects. The design of two stage fuzzy controller and its parameters are discussed. The system simulation shows that the control scheme can make the tension within the stable range.

Abstract: The rotary control orifice, in which the relative angular openings are adjusted by the rotary motion of the spool, thus controlling the flow area and the flow passing through, is a basic control element of hydraulic control valve. It has several advantages, such as little minimal steady flow rate, good anti-contamination, small driving power, small opening and shutting shock, and etc., over the translational control orifice. The working medium is tap water. A model is developed and numerical studies are carried out to investigate the hydrodynamic characteristics of the rotary control orifice, including flow and pressure field, flow characteristics, flow torque. The relationships between the flow and the pressure drops, the efflux angle and the angular openings, the steady-state flow torque and the pressure drops as well as the angular openings are obtained. The results show that a) the orifice geometries have great effects on the efflux angle and the steady-state flow torque; b) Under the same openings and flow direction, the efflux angle is almost constant under different pressure drops. It is larger for meter-in flow than for meter-out flow and decreases with the increase of openings; c) The steady-state flow torque (including meter-in flow Tsfin and meter-out flowTsfout ) is proportional to the pressure drops and first increases and then decreases with the increase of openings, finally reaches zero at the fully opened position; d) The friction moment is proportional to the rotary speed so as the transient flow induced moment to the rotary acceleration. The in-depth study of the drag moment of rotary control orifice helps to design high performance rotary servo valve for robots. The in-depth study of the rotary control orifice provides a basis for developing high performance rotary control valve.

Abstract: According to APDL language of ANSYS, this paper establishes the ideal identity model of tooth profile and gear based on ideal tooth profile equation, and it gets the ideal gear profile in meshing period and change curve of maximum contact stress with position of gear meshing. The result indicates that the contract stress distribution of ideal gear profile presents certain regularity with meshing state of double gear. Gear module can not change the stiffness value of gear meshing; increasing the number of driving wheel can reduce meshing stiffness. Finally, this paper gets the curve of meshing stiffness changes with load. The result indicates that the effect of load on deviation and tooth profile and gear meshing is larger than that on idea tooth profile and stiffness of gear meshing.

Abstract: One of the inevitable problems in the missile launchers is vibration, which can lead to failure of missile launchers. The3D model of the missile launchers is created and the modal analysis is adopted by the ABAQUS. The results show that the missile launchers will have resonance. The vibration mode diagram of the missile launcher’s structure is analyzed and the weakness of the missile launchers was found. The theory for the missile launchers design and manufacture is provided.

Abstract: Wing skins play a vital role on the wing structure as well as the inherent characteristics of the wing. The thickness of the wing skins affects many of the key parameters of the wing. To study the impact of the thickness of the wing skins on the modal characteristics of the wing, and to preferable for the thickness of the wing skins, a certain type of aircraft wing model as an example, we carried out on the wing modal analysis and preferable the thickness of the wing skins based on Abaqus. The calculations show that the thickness of the wing skins are all affected on each wing modal frequencies, modal size of displacement and stress.

Abstract: By using the parametric design language APDL, developed ellipsoidal reticulated shell parametric macros, only enter the long axis S₁, short axis S₂, high vector F, scale factor t, ring symmetric region shares Kn, radial nodes turns Nx, to generate the desired lattice shell; comparative analysis of 30 kinds of scheme through two types of single-shell ellipsoid reticulated shell with different rise span ratio force, studied its stress characteristics, providing a theoretical reference for designing and engineering ellipsoid reticulated shell application.

Abstract: This paper first used parametric design language APDL to establish three kind of the single hyperbolic paraboloid shell model with rectangular projection. The parametric design of the reticulated shell structure could be realized after inputting the span (S),rise (F),the grid number of each side (Kn),the warping rate (K),which provided great convenience for optimizing the structure and force analysis.Then through contrasting three structure schemes and different warping rate,it studied how they influence the mechanical properties of structure.And at last it got some conclusions with engineering significance.

Abstract: For rotational parts with irregular curve profile, in order to achieve its manual programming and machining, we need to segment the contour curve according to the change of curvature. Through the calculation, we can get the minimum arc to fit the segments, and calculate the circular endpoint coordinates and radius by using the drawing methods. Finally, we develop the NC program. By the analysis of the result, we find the method can simplify the programming and improve machining efficiency.