It is a. Figure 1. Nominal strength change law for openings of different diameters and typical failure of sample. Figure 2. Typical stress-strain curves of samples without opening and sample with 6mm opening. When formula 2 is met, failure occurs on the plate with opening hole. Stress analysis is conducted under linear condition for the semi-infinite plate with opening hole, obtaining the ratio of the strength of plate with opening hole to that of plate without opening hole:.
As a geometric parameter relevant to the failure region, a specific physical interpretation has not yet been given for , which generally can be obtained by finite element calculation and test. Considering the stress distribution obtained by finite element method has some human assumption factors, in this paper, the characteristic dimension is obtained from the measured strain data of a test specimen with 6 mm opening hole under tensile failure load, which is 4.
According to tensile and in-plane shear test specimen without opening hole, obtain that , , , substitute these data into the above formulas, obtain the ratio of the strength of plate with opening hole to that of plate without opening hole, which is 0. Thus, this shows that the point strength criterion, as a simple but effective forecasting method, has a good applicability in the test. The reason why the theoretical result is slightly higher is that the directly used characteristic dimension measured from the test is slightly larger, which should include the influence of test error, dispersion of subsample and distinguishing method of singular data near the failure load.
Correct the theoretical result, then a relatively identical and safe result can be obtained when.
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The characteristic dimension is relevant to several factors such as material, opening hole size, edge condition, etc. To different practical situations, it should be determined through a large number of tests.
The bearing capacity of circular shaft is the key of thermal structure such as rudder and flaperon, etc. The stress state near the position of opening hole is complicated, which needs to consider many factors. To ensure enough loading transfer capacity, the circular shaft is usually adapted as bolted joint with double-column and even multi-column opening hole. So, it is necessary to analyze the effect of extruding and tensile load to each hole, and to ensure the bearing rationality of the hole in each column.
Establish the relationship of ratio between the extruding and tensile stress of the loaded hole of shear bolted joint sample, which can reflect the combined action effect of the two. The formula is determined through below:. According to the formula in related article   and using the test specimen with 8mm opening hole in this paper, the sketch map of failure envelope for a single opening hole under the combined action of tension and extrusion is shown in the figure below.
Extrusion failure occurs on the joint structure in the grey OAB area, and tensile failure occurs on the joint structure in the white OBC area. By Figure 3 , tensile failure should be more attention for this sort of opening hole. For the actual circular shaft, factors need to be considered when structural design include shape of opening hole, size dimension, interval and stiffness of connecting bolt, moment of pre-tension and interval, etc.
It is necessary not only to achieve the optimization under normal temperature, but also to consider the possible influence of high-temperature thermal expansion and additional heat stress. Under normal conditions, the need for large diameter of opening hole of circular shaft and for proper stiffness of bolt is somewhat contradictory. By notching or hollowing, the stiffness of metal bolt with large diameter can be reduced, so as to achieve the stiffness matching of multi-column bolt. Changing the shape of opening hole moderately can reduce stress concentration for special load condition, which can be achieved through bolt bushing in the structural design.
Choose the above factors as the variables to make numerical analysis and optimized design. Under initial design condition, the ratio of load bearing of column 1, 2 and 3 bolt i. Figure 3. Figure 4. Opening hole joint and high and normal temperature bearing test of typical circular shaft. Each opening hole tends to bear a uniform load. Additionally, the distribution of the extrusion load and the bypass load is more reasonable, and it also considers the influence of high-temperature heating. The test result verifies the effect of the optimized design, and that the circular shaft failure does not occur at the position of the opening hole.
And the specific stress concentration sensitivity coefficient and the characteristic length by strength criteria focused on particular point are obtained in this paper. However, there are a lot of factors involved in connection of opening hole of the actual structure, so it is necessary to make a reasonable optimization.
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Thus, the typical circular shaft is applied in this paper. With respect to the relevant follow-up work, study on mechanical properties of opening hole of a typical test specimen under high temperature will be conducted, to discuss the coupling property and heat matching characteristic of heat stress and external load stress. Moreover, the testing technique and the oxidation resistance technique under high temperature are both difficulties that need to be solved.
Shanghai Jiaotong University Press, Shanghai. Aeronautical Manu-facturing Technology, S1, Chinese Quarterly of Mechanics, 29, Journal of Composite Materials, 32, Materials and Design, 28, In: Tong, L. Share This Article:. In this Track, we would like to discuss intensively about the most recent topics about composite application technologies for automobile and rail vehicles.
Contributions concerning not only finite element analysis, but also topics such as cost analysis, material selection, high volume process technology, multi-material strategy, and structural design concepts are welcome. Over the last couple of decades composite materials have made significant inroads into the offshore oil and gas industry. The versatility of composites, and their superiority in terms of mechanical properties, corrosion resistance and light weight have helped to pave the way. Continued demand for oil and gas, coupled with declining production from existing fields, has pushed exploration and production activities to harsher and more challenging environments, which has also opened up many opportunities for the application of composite materials in the offshore oil and gas industry.
This Track is set up to solicit and bring together papers that describe and discuss actual field applications of composites in offshore oil and gas facilities and environments, covering fixed and floating structures, as well as offshore and subsea repairs and rehabilitation, and health monitoring systems, amongst others. Composite materials of all kinds, including but not limited to reinforced elastomers, thermosets, and thermoplastics, as well as ceramic and metal based composites would also be of interest.
The topic of qualification of the materials for such applications is also welcomed by this Track.
Key words: Pleasure craft, lifeboats, high-speed craft; ships of all kinds including passenger, cargo and naval vessels, ferries and offshore service vessels; appendages. Small and medium-sized boats — pleasure boats, racing yachts, coastal rescue vessels and lifeboats — were among the first commercial applications that made extensive use of composites.
More recently developments in fire protection, and in safety philosophy, combined with environmental and fuel efficiency considerations, have led to more widespread use of composites, not only in high speed vessels but also in larger commercial ships. Newer applications include large components such as hatch covers for bulk cargo ships, tanks for marine transportation of compressed natural gas, propellers, and large parts of ship superstructures, as well as new ship concepts such as eco-ferries and ships serving offshore wind farms.
High performance sailing yachts have led to rapid innovation in materials usage, structural design and manufacturing methods for hulls, masts and appendages such as rudders and dagger-boards. A feature of marine applications is the wide range of material systems used from low-technology spray layup through to autoclave prepreg, with different cost-performance requirements depending on the application.
The track will cover all aspects of these applications including design, concept development, structural analysis and characterisation, water impact, fire performance and risk assessment, manufacturing processes, condition monitoring, effects of environment, non-destructive testing and forensic engineering. Composites are used widely in naval ships, and many of the technological developments that have found application in passenger and cargo ships as well as patrol vessels have occurred in that context. The US Office of Naval Research will be organising a special symposium presentations by invitation only at ICCM that will be devoted specifically to naval applications and associated research.
Track will also accept contributions in this area. Key words: Bridges, buildings, towers, piles, poles; road, tunnel, and geotechnical construction. Track Applications in Civil Engineering aims to provide a forum where engineers, researchers, practitioners and industrial partners in the field of composite materials are invited to discuss and share recent advances and developments and future perspectives of applications in civil construction and infrastructure.
It will cover all aspects of applications of composite materials including:. This Track will focus on the practical application and implementation of composite materials, and the technology in development for various aerospace fields including commercial and general aviation, and satellites and space structures.terdinscountmicti.cf
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The performance advantages associated with reducing the weight of aircraft structural elements has been the major impetus for aviation composites development. Composites are also being used increasingly as replacements for metal parts on older planes. The use of composite materials has also made it possible to achieve a number of milestones in space technology. Particularly, the stringent requirement for dimensional stability and weight reduction can be met only by the use of advanced composite materials.
Material and process development, design methodologies, qualification programs and long-term performance are some of the research areas that affect structural integrity, producibility and performance in the aerospace industry. All of these aspects may be considered within the scope of the Track. Key words: Application of blades and other composite structures for wind, wave, tidal and ocean current energy conversion. This track covers the application of composite materials in renewable energy technologies such as wind, wave, tidal and ocean current energy.