Abstract: This article deals with presentation of data processing obtained from imaging CT (computer tomography) and micro CT devices. These methods enable to perform bone tissue density analysis by non-invasive way. The image processing methods, by which it is possible to determine mechanical properties of bone tissue, are described in this paper. Further, a creation of a computational model with different bone density of cancellous tissue is described and afterwards the stress strain analysis is performed. The mandible segments with different bone density were used as samples. Results show significantly higher stresses are reached in a cancellous bone tissue with worse bone quality.
Abstract: Complex hierarchical assembly and presence of large amount of organics and water content are responsible for enough amount of plasticity in bone material. Plastic properties are not only important to assess the various changes and fracture risk in bone but also for the development of better bone implants and joint replacements. The present study is focused on the post-yield behavior of cortical bone. The plastic properties of goat femoral and tibiae cortical bone were assessed and compared in terms of plastic modulus (H), tangent modulus (Et), plastic work (Wp) and plastic strain (εp) using uniaxial tensile test. Both femoral and tibiae cortical bone were found to be having similar post-yield behavior and significant stiffness loss was observed in both the bones during plastic deformation. The value of plastic modulus for femoral cortical bone was found to be 1.2 times higher as compared to the corresponding value for tibiae cortical bone. This shows higher hardening rate for femoral cortical bone. It was also observed that femoral bone requires higher energy during plastic deformation until fracture as compared to tibiae cortical bone.
Abstract: The microstructures, mechanical properties, corrosion behavior, and biocompatibility of hot-extruded Mg-Zr-Ca alloys have been investigated for potential use in orthopedic applications. The microstructures of the alloys are examined by X-ray diffraction analysis and optical microscopy. The mechanical properties of Mg-Zr-Ca alloys are determined from compressive tests, the corrosion behavior is studied using immersion tests, and biocompatibility is evaluated by cell growth factor using osteoblast-like SaOS2 cell. The experimental results indicate that the hot-extruded alloys have much higher compressive strength than the as-cast alloys and the human bone, and can offer good mechanical properties for orthopedic applications. The hot-extrusion significantly enhances corrosion resistance of the alloys. Among the alloys, the hot-extruded Mg-0.5Zr-1Ca and Mg-1Zr-1Ca alloys possess good combination of mechanical properties, corrosion resistance, and biocompatibility, suggesting that they have a great potential to be good candidates for orthopedic applications.
Abstract: In modern civil aviation operations, the effective performance of pre-flight flight planning is the key of a safe flight, and the changing air traffic environment often requires modifying the pre-determined flight plan or even en route re-planning. This paper proposes an integrated system framework for the construction, re-planning, rehearsal and evaluation of computerized flight plans (CFP): the flight plan management and rehearsal system (FMRS). It provides interactive, graphic user interface - based ways of constructing flight routes using the navigation database and geographic information system (GIS), and the CFP parameters can be calculated automatically based on real performance data of various types of aircrafts. Simulation models of aircraft dynamics and airborne subsystems including the automatic flight control, navigation sensors and cockpit instruments are also integrated to support the rehearsal and evaluation of flight plans, and assist in analyzing en-route re-planning operations. All subsystems and components are integrated into an overall platform which is based on an inter-communication architecture and can be implemented on either centralized or distributed simulation platforms. Simulation and system evaluation results obtained from actual commercial flight routes demonstrate that the proposed system can effectively facilitate the preparation and evaluation of CFPs, and support the CFP re-planning decision-making process and operations.
Abstract: The root cause of wing rock is investigated by examining two slender delta wings (700 and 850 sweep back angle) in wind tunnel using force measurement, pressure measurement and PIV techniques. The results show presence of asymmetric flow at 200 angle of attack and initiation of wing rock at the same point for 850 model while there is neither asymmetric flow nor wing rock for 700 model suggesting close relation of flow asymmetry with wing rock. Investigation with three apparently identical nose sections reveals that the asymmetry comes from the area very close to the wing tip. This asymmetric flow causes the vortices to interact in a complex way resulting in wing rock when the vortices are in close proximity (such as for 850 model), which is not the case when the vortices are ‘comparatively away’ (such as 700 model) from each other.
Abstract: The core of airplane lifecycle data management is BOM management in the product lifecycle. Aiming at the problem of nonunique data source existing in airplane lifecycle, the paper proposes the airplane BOM management hierarchical system framework based on Single Source of Product Data ( SSPD) and the corresponding technology. The logical unified SSPD is constructed to guarantee the uniqueness of lifecycle data. According to the diversity and complexity of airplane，customer options management and BOM management based on SSPD, are discussed emphatically in the context.
Abstract: A novel design in micro-air-vehicle using flapping rotary wings with different wing spanwise length and area is proposed. With the wings flapping, produced thrust makes the wings rotation. Furthermore, lift force from rotary wings increases and overcomes the MAV weight. On the basis of this principle, a mechanical model is made and sample experiments of averaged lift measurement in different wing length and area and angle of attack are executed. It is shown that the maximum averaged lift produced by micro flapping rotary wings can reach to 80mN approximately close to the weight of MAV.
Abstract: A hierarchy-structured predictive control(HSPC) method is proposed according to the feature that hypersonic flight vehicle(HFV) model is highly nonlinear, fast-variability, coupling, and with parameters of great uncertainties. This method contains two parts, which are inner-loop nonlinear generable predictive control(NGPC) system and outer-loop NGPC system, respectively. These two NGPC systems are both designed by closed-form optimal generable predictive control(GPC) method. The HSPC system can ensure the longitudinal flight stability under the influence of uncertain parameters. Simulation studies demonstrate that the proposed control method is feasible for hypersonic flight vehicle.
Abstract: The friction stir welding technology is a new type of welding technology of solid phase, with advantages of high quality, few defects, and small deformation in joint, which has obvious advantages in welding light alloys of aluminum, magnesium and other new materials, which will replace the traditional resistance spot welding and riveting technology to be one of the main manufacturing methods of aerospace industry, and has wide application prospects in this industry, which have great significance in upgrading the manufacturing level of aerospace industry, reduce the production cost and improve our manufacturing technology.
Abstract: The problem of data fusion based on filter is studied for an integrated inertial navigation system / Beidou navigation system / global positioning system (INS/BNS/GPS) with uncertain noise and conditionality of using GPS. The integrated navigation system can be divided into two integrated navigation subsystems (INS/BNS and INS/GPS). The signals from GPS and BNS receivers are easy to be disturbed, so filter is used to estimate the subsystem errors which are transmitted to fusion center online. Then data fusion is carried out by using the fuzzy fusion algorithm. Simulation results show that the algorithm can improve the accuracy and stability of navigation system.