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In this study, 12 commercially available paper towels were collected from the local market. Their tensile properties were investigated by Kawabata Evaluation System for Fabric (KES-F). Four tensile properties namely: (i) extensibility (EMT), (ii) tensile energy (WT), (iii) tensile resilience (RT) and (iv) linearity of WT (LT) were evaluated. Experimental results revealed that the tensile properties varied within the products. EMT was used as the key property for discussing the tensile properties of paper towels. However, when the different tensile properties were correlated, it was found that WT/RT, WT/EMT and RT/EMT had strong Pearson correlation. In addition, there was no significant statistically relationship between weight and thickness to EMT. Based on this study, it can provide some information about the tensile properties of paper towels in local market which may help the industry for further improving the product quality.

In this study, we chose 12 commonly available paper towels from the local market. The compression properties of the paper towels were examined by Kawabata Evaluation System for Fabric (KES-F). Three compression properties namely: (i) compressional linearity (LC), (ii) compression energy (WC) and (iii) compressional resilience (RC) were examined. The experimental results revealed that the compression properties varied within the different paper towels. RC vlaue was used as the key property for discussing the compression properties of paper towels. When different compression properties were correlated and analysed, it was found that no relationship was noted within different compression properties. On the other hand, there was not significant statistically relationship between weight and thickness to RC. It is hope that the results from this study can help the indurstry to improve the compression properties of paper towels for local market.

In this paper, we collected 12 commercially available paper towels from the local market and their shearing properties were evaluated by Kawabata Evaluation System for Fabric (KES-F). Three properties namely: (i) shear rigidity (G), (ii) shear stress at 0.5º (2HG) and (iii) shear stress at 5º (2HG5) were studied. Experimental results revealed that the shearing properties varied within the products. G was used as the key property for discussing the shearing properties of paper towels. However, in correlating different shearing properties, it was found that 2HG and 2HG5 had strong Pearson correlation. However, no significant statistically relationship between weight and thickness to G was found. This study may provide data for the industry for the improvement of shearing properties of paper towels for local market.

12 commercially available paper towels were collected from the local market and studied in this paper. Kawabata Evaluation System for Fabric (KES-F) was used for evaluating their bending properties. Two bending properties namely: (i) bending rigidity (B) and (ii) bending moment (2HB) were evaluated. Experimental results indciated that the bending properties varied within the products. B was used as the key property for discussing the bending properties of paper towels. When the correlations of different bending properties were investigated, it was found that no significant was found between B and 2HB. However, there was significant statistically relationship between weight and B but no relationship between thickness and B. With the use of the results, the product developer could improve the bending properties of the paper towels.

In this study, 12 commercially available paper towels were collected from the market. Their shearing properties were evaluated by Kawabata Evaluation System for Fabric (KES-F). Three properties namely: (i) coefficient of friction (MIU), (ii) deviation of MIU (MMD) and (iii) geometric roughness (SMD). Experimental results revealed that the surface properties varied within the products. When different properties were correlated, it was found that there was not significantly relationship between MIU, MMD and SMD. However, weight and thickness had well statistically relationship to SMD.

The force analysis on the in-plane and out-of-plane of honeycomb core referring to some related articles is presented. during the transportation of wine, the honeycomb paper core is under three-dimensional stress. According to stress condition in the process of wine packaging and transportation, based on the fourth strength principle, the equivalent load is obtained. And the stress with different stretching angels with virtual sampling method is calculated. Thus, the optimal stretching angle of honeycomb paper is acquired, which is .

Two equivalent models based on sandwich panel theory and equivalent panel theory were discussed in this paper. By analyzing the performance of fiber - paper honeycomb sandwich structure compound panel by bending load, the computational results are in accordance with test and Engineering software ANSYS. Therefore, it shows that the finite element equivalent models are reasonable and practical for the optimization design of fiber - paper honeycomb sandwich composites.

Modal analysis was done to steel shaft and rubber shaft, and their top ten orders of nature frequency were obtained. The lowest nature frequency of steel shaft is 64HZ and the rubber steel’s is 2.2463HZ. Doppler vibration measurement was done to main shaft of paper advance mechanism and the time domain signal and frequency domain signal were obtained when the rotational speed is 80, 160, 240, 320, 400 Rpm. The frequency and amplitude were obtained by signal analysis. It proves that the nature frequency of steel main shaft is much higher than measuring result, but the seventh and eighth order nature frequency of rubber material is in accord with measuring result of laser doppler vibration.

the paper introduces the advantages and disadvantages of the honeycomb core composite wallboard, and put forward various solutions on the problems that the honeycomb core composite wallboard on juncture place easily crack. According to the advantages and disadvantages, the optimal measures are to use CFRP paste connection joints. Tested by experiments, the results show that: for using cellular wall materials as new buildings retaining wall materials, CFRP enhancement processing juncture surface can effectively restrain cracks, and the results are ideal; for existing buildings retaining wall, gives suggestions about enhancement processing, and proves its feasibility.

The sandwich external wall panel is made of fireproof Paper Honeycomb Board (PHB) as kernel material, and the external surface is covered by colorful extruded steel board, while the internal surface is coated with the thermal insulating frothing ceramic board or the calcium silicate board, which works as the insulating layer or protecting layer of the panel. Two types of formation design are suggested, i.e., Type-A and Type-B. After corresponding thermal calculation, the maximum thermal transmission factor is determined as 0.424W/(m2• K), which complies with the threshold stipulated in the National Code for external wall panel used in cold climate area. The newly designed wall panel will save 65% of energy when compared with the traditional one made in 1980.

The theory of natural frequencies were acquired from vibration experiment, meanwhile, the first order frequencies of honeycomb sandwich structure composites were obtained by using the sandwich laminboard theory and equivalent panel theory via the finite element software ANSYS. The simulation results were compared to the experiment results to get the error of calculation of the two different equivalent methods, thereby we can select more appropriate equivalent method to ensure the veracity of the result analysis and provide a reference for the optimization design of the fiber-paper honeycomb sandwich structure composites.

EPS, XPS and PU plates etc. are often selected as the insulating layer in external thermal insulation system. Although featured by good thermal insulation properties and low costs, these materials are provided with major fire potential. Therefore, fireproof treatment methods for the thermal insulation materials and fireproof structural measure for the system are proposed in this paper based on the combustion tests on the thermal insulation materials, so as to increase the fire protection safety of the external thermal insulation system.

In order to improve the spine tape folding precision of GMS-7 type spine taping machine and reduce the labor intensity, this paper researched the principle of the spine tape folding process.Through analysis and calculation, the relation curve between folding angle and the advancing distance of paper tape is obtained, therefore, achieved is the free form feature of plow shaped guideways that provides the method to brush the paper tape on the spine of promissory note with glue smoothly.

Under external loads, the continuously prefabricated slab of double-block ballastless track may crack easily. The cracks will reduce the durability and carrying capacity of the roadbed slab. Moreover, the cracks may also affect the use and safety of the double-block ballastless track during its service. When the roadbed slab crack, we should take some maintenance measures to maintain the normal use and durability of the double-block ballastless track. This paper based on the finite element method, established a beam-brick model for double-block ballastless track which has a through crack on the roadbed slab to analysis what kind of patching material is the most suitable when the most unfavorable loads act on the track. For this reason, we can provide theoretical basis for maintenance of double-block ballastless track .

At present, China's large span continuous rigid frame bridge (CRFB) has made rapid development, and has been applied in the railway bridges. This paper based on finite element analysis software ANSYS, using the simplified algorithm, establish a line - bridge - pier integration model for calculation of continuous welded rail (CWR) on bridge, the continuous rigid bridge and continuous rigid frame bridge (CGB) in two different conditions were compared and analyzed. The calculation results show that: the rail expansion force, bending force, braking force, rail broken gap of CRFB are smaller than that of the CGB of same beam span, in CWR, CRFB has obvious advantages, it should be popularized.; equivalent temperature span of CRFB are smaller than that of the CGB of same beam span, so the CRFB is less affected by the temperature; because of the pier and girder consolidation of CRFB, favorable to CWR, but due to the bending effect of bridge piers can lead to beam produces larger vertical deformation, thus affecting the track smoothness, which must be noticed in design.

This paper based on the unified strength theory, analyzed the ultimate bearing capacity of the reinforced concrete columns combined with FRP under axial loads. First, analyzed the mechanical property of the RC columns combined with FRP. Second, based on the unified strength theory, deduced the three-direction compressive stress of the core concrete and got the unified formula for calculating the ultimate bearing capacity of RC columns combined with FRP. Last, compared the analytical results obtained in this paper with the relevant experimental data, good agreement can be found and it proved the good applicability of the formula. Comparing with other methods in calculating the ultimate bearing capacity of RC columns combined with FRP，this method is well-founded, so it has a significant value in analysis of RC columns combined with FRP.

Infill walls,etc. non-load-bearing walls are vulnerable to fracture when these are subjected to out-of-plane seismic loads. Studies suggest that the overall dimensions of non-load-bearing walls are the important parameters to affect its out-of-plane mechanical properties, but most of these researches are qualitative researches, do not give specific size limitations. This paper based on codes has calculated out-of-plane loads of non-load-bearing walls, then bearing capacity check formulas have been deduced when non-load-bearing walls are subjected to out-of-plane seismic loads, finally the size limitations used in the height-thickness ratio check and seismic check are obtained.The conclusions fill up gaps in research of non-load-bearing walls ,and provide reference for the design specifications of non-load-bearing walls.

This paper based on the improved twin tripod sliding universal joint and let it has the determined movement output. And create the three-dimensional model of twin tripod sliding universal joint before and after improved in software pro/e, and then put it into the simulation module, carry out the kinematic simulation of the tripod center on coupling. Obtained the curves of displacement, velocity and acceleration for two kinds of tripod centers.

A precise approach for the tooth profile modification (TPM) of helical gear is presented in the paper based on the static contact finite element analysis (FEA). The high-precision finite element model of helical meshing gear pairs is established. The type and amount of TPM are accurately determined by the static contact FEA results. The dynamic contact simulations of helical gears with and without tooth modification are investigated to estimate the vibration reduction effect of the TPM. Moreover the numerical simulations are compared with the experimental results. Both results show that the proposed precise TPM of helical gears is effective on vibration reduction around the working load, and the dynamic contact simulation is effective on estimating the vibration reduction influence of the TPM.

In order to ensure the dimensional accuracy of housing with small fillets, various forming factors have been analyzed in this paper based on finite element simulation. Through the analysis of the forming factors, the principle of die angle selection, the proper reverse drawing height in sizing process, sequence of sizing and applications of local sheet bulk metal forming in housing production were put forward, and some forming laws of housing with small fillets were concluded.

It is difficult to reach the request that 65% standard of building energy in china and the goal of China’s science and technology development in 2020 using traditional outer insulation technology. The several combinations of ordinary concrete (1) and bearing ceramsite concrete (2), styrofoam board of external thermal insulation for external wall (3) and cement-based glazed hollow bead insulation system (4) are made thermal calculations and cost analysis separately in this paper based on a practical project of Jiaozuo city. The results indicate that the combination of (2)+(4) is the best one, which reduces the energy saving rate, labor intensity, transportation weight, project cost by 74%, 20%, 30%-40% and 10% respectively.

Aiming at the reliability of Q345 steel material impacted on high temperature and dynamic shock load, its mechanical properties are studied in this paper based on the split Hopkinson pressure bar, the SHPB test facility is introduced in detail. And the stress-strain curves of Q345 steel are obtained in the special industrial condition. The flow stress decreases clearly in pace with the increasing of temperature, which provides credible technique evidences for the maintenance and health appraising of the structure.

A railway bridge over several decades will be degraded due to localized corrosion. As a result, the load capacity of the bridge decreases, especially under the live load caused by trains. This paper examines the residual load capacity of a bridge deteriorated by localized corrosion by using the multibody dynamics approach. This approach allows an accurate description of the interaction between trains and bridges. At the same time, it allows the formation of corrosion marks on each structural member of the bridge in a numerical model precisely based on actual measured data. In order to describe accurately the remaining load of the bridge under the moving load of the train, a dynamic testing and finite element modeling of a steel bridge are conducted and compared. At the same time, the results are also compared with the simulation results of the bridge model before being corroded. In addition, the paper also tests the reliability of the numerical model for assessments of similar bridges without actual measurement results that are costly and time-consuming.

The demand for high accuracy on automated harvesters is getting higher. While system accuracy is lowered by vibration resulted when a robot with sensors and arms is running on the field. Applying suspension system onto these automated harvesters is a solution to reduce the vibration effects and assure required accuracy. This paper presents a model of the suspension system for a robotic asparagus harvester. The simulation results showed that the peak value of vibration was reduced to an acceptable level. Most importantly, the peak deflection of a vibrated platform was decreased to a required range as well. At the end of this paper, a conclusion is drawn. A suspension system is suggested to reduce vibration effects and improve the accuracy of both sensors and picking arms for mobile manipulators. In the future, this suspension system will be fabricated and installed onto a robotic asparagus harvester to validate this proposed model.

Northeast Extreme Tee (NEXT) beams have been recently developed for the accelerated bridge construction. The skew effect on live load distribution in a NEXT beam bridge, especially with integral abutments, is not clear and shall be assessed. In this paper, various skew NEXT beam bridges are evaluated through validated finite element (FE) analyses with solid brick elements. Parameters as studied include beam section, span length, and skew angle. Per AASHTO LRFD specifications, one- and two-lane loaded cases are examined to obtain the maximum tensile strains in beam stems under the design live loading (HL-93). Unskewed bridges are used as control specimens to compute skew reduction factors (SRF) for moment from the obtained FE strains. The FE- and LRFD-SRFs for moment are compared in terms of figures, which indicate the LRFD-SRFs have good agreements with the FE-SRFs at large. For the majority of the bridges, LRFD-SFRs govern the FE-SRFs. The research findings from this paper are useful for practicing engineers to safely design a skew NEXT beam bridge with integral abutments.

To control the vibrations with passive suspension system having limitation with constant damping force. By using smart material like magnetorheological fluid, it is possible to control the damping performance of suspension system using current variations in magnetic coil. Applications of this kind of damper are in front loaded washing machine and damper use in driver seat of heavy duty vehicles. Mainly flow mode MR damper is most commonly used damper for these two applications. This paper represents theoretical model and optimized design of flow mode MR damper. For any kind of MR damper design of magnetic coil is play very vital role. So for this paper mainly includes the design of coil and different parameters like number of coil distance between two coil current passing from the coil is consider for design and optimization using FEMM software. This work also includes the theoretical study of MR damper characteristics with force-displacement and force velocity plot with change in piston diameter and fluid gap.

In this paper, the reliability and reliability sensitivity of the main shaft device of a hoist system is studied. The main purpose of this paper is to provide a modeling method for the joint probability distribution of main shaft device with coupling faults based on the system reliability theory and copula function theory. The stochastic response of the main shaft device is obtained using design of experiment. The reliability of the main shaft device is calculated based on the fourth moment method. The reliability sensitivity is then deduced based on the reliability results. The joint probability of failure between correlated failure modes is estimated based on the Gumbel copula. The system reliability evaluation of the main shaft device is then calculated. A numerical example of a main shaft device is illustrated to validate the application of the proposed method. The method proposed in this study can be provided for the analysis and design of the main shaft device of deep well hoist as a necessary theoretical basis.

Multilayer cutting is widely used in finish machining process of thin-walled parts to improve the machining precision. The paper presents a cutting allowance optimization method using genetic algorithm to improve the machining quality and efficiency of thin-walled parts in the field of aerospace. Considering the coupling relationship of the deformation between the layers in layered milling, the parameterized finite element model of thin-walled parts in side milling process is established. The best relationship between the workpiece stiffness and the cutting force is determined though iterative calculations, and the deformation caused by the cutting force can be minimized. The results show that the optimized distribution of the depth of finishing cutting was better than the experience. The method proposed in this paper can reduce the deformation of the workpiece during the machining process, and thus improve the machining accuracy.

Facing the energy crisis and environmental problems, saving energy of construction machinery, especially in the hydraulic excavator is very important. Regeneration of the potential energy is an effective solution to save energy. However, the conventional hybrid excavator can’t regenerate the potential energy. This paper proposes a new structure of boom system of hydraulic excavator as well as a control strategy. The focus of the paper is using hydraulic transformer to regenerate energy and reusing the regenerated energy. The simulation is carried out by the AMESim software. From the simulation results, this new system has a high efficiency for energy saving.

Many masonry domes in their lower portion are subjected to hoop tensile forces which mostly lead to vertical cracks appearing along the dome's meridian planes. A close inspection of any such dome reveals these hoop tension cracks. The dome stands as a series of arches with common key stone, with cracks as a matter of non-structural consequences. Different strategies have been considered historically to arrest these cracks. The provision of tension ring mechanism adds to the stability of these domes, and hence many masonry domes are retrofitted with the provision of the tension rings using steel and FRP rings. The challenge in such retrofitting will remain to analyze its effect on stability of these masonry domes, more specifically in absence of reliable mechanical properties of such masonry domes. This paper presents a simplified analysis procedure combining thrust line analysis with the finite element analysis called here as Finite Element Thrust Line Analysis (FETLA). The development of a new element suitable for masonry dome analysis to include the effect of hoop tension cracks is demonstrated. The orthotropic material properties are utilized for penalty approach to allow redistribution of the forces from meridian direction to the hooping rings, with thrust line approaching the extrados or intrados of the dome. The analysis results of FETLA are validated with the previously available results. The analysis method proposed in this paper gives the rational estimates for the failure load without utilizing inelastic properties of the material to model the hoop tension cracks and its propagation.

The prefabricated roller blind lintels have become common solution, particularly for the single-leaf masonry structures without external thermal insulation system. These lintels, representing simple system solution, are designed to interrupt thermal bridges in a place of above the window lintel and simultaneously to provide sufficient reliability of load transfer. The actual outdoor blinds contribute to increase the thermal stability in the room in summer and winter season. They prevent overheating of the room in the summer months and reduce heat transmission through a window in the winter. This paper is focused on the design and numerical modelling of the prefabricated roller blind carrier lintels solutions. Methods of elimination of the thermal bridge are demonstrated on the example of a real produced prefabricated lintel. At the same time this paper deals with its structural analysis. Analyses were carried out using the method of numerical modelling, using finite element method and computing software ANSYS.

In order to break through the limitation of the width of river, depth of water, channel and etc., it is an optimal choice to construct a long-span suspension bridge. In a suspension bridge, the main cable is the major bearing member; and the use of super high strength cable wire can lighten the dead weight and obtain an economical design. 1960 Mpa cable wire is adopted by an under-construction suspension bridge, namely Ni-Zhou Channel Bridge, for the first time in China. In this paper, taking the Ni-Zhou Channel Bridge as a case-study, comparative analyses on dynamic characteristic and seismic response of long-span suspension bridge with 1960 Mpa cable wire are performed. Firstly, dynamic calculating model for Ni-Zhou Channel Bridge is built and its dynamic characteristics are studied; then by using response spectrum and time history analysis method, seismic response of Ni-Zhou Channel Bridge is investigated on the basis of design response spectrum and artificial seismic ground motions; finally, the energy dissipation performances of a seismic protection devices (viscous damper) are also discussed. The results show that long-span suspension bridge with 1960 Mpa cable wire has a longer natural vibration period; the use of viscous damper can effectively reduce the peak value of bending moment in stiffening girder. This paper can provide references for the project’s construction.

Engineered cementitious composite (ECC) is a class of high performance cementitious composites with pseudo strain hardening behavior and excellent crack control. Substitution of concrete with ECC can avoid the cracking and durability problems associated with brittleness of concrete. In this paper, it is aimed to design a scale model of ECC reinforced concrete precast shear wall structure. Referencing the prototype structure which is a precast concrete shear wall structure in Nantong, Jiangsu Province, China, the size similarity constant is taken as 1/2. Consulting the scale similarity conditions, the similarity similar constants representing material characteristics, geometrical features, and load characteristics are calculated using the strength similarity theory. Besides, the reinforcements in the model structure are calculated and analyzed. The diameters of reinforcing steel bars in the model structure are determined by the principle of similar size. Equivalent principle of yield bearing capacity are used when there is no corresponding reinforcement selection. The research results of this paper will provide valuable preferences for design and analysis of ECC reinforced concrete precast shear wall structure.

Reinforced concrete (RC) is the most popular building material in the construction industry. It is a composite material in which low tensile strength and ductility of concrete are counteracted by the inclusion of reinforcement having higher tensile strength and ductility. The RC based structures are required to be replaced after their life time. Complete replacement will be a huge financial burden and might certainly be a waste of natural resources when upgrading or strengthening is an adoptable alternative. Strengthening can be achieved through retrofitting. The meaning of retrofitting is addition of new technology, components, accessories or features to older systems. Retrofitting may be required when the structure needs to be used for a purpose dealing with more load compared to design loads. It may also be used where old structures are needed to be upgraded. This paper is focused on the retrofitting of simply supported RC beams. Various materials like polymers, cementitious composites, steel sections etc. are used for retrofitting of RC beams. For the addition of these new materials to the existing ones, various techniques are used. This paper is a review of the materials and techniques used in retrofitting process of RC beams in existing buildings. The effectiveness of each material and technique is also reviewed.

Diagrid structures are exterior structures, consisting of diagonal struts and ties in the periphery and an interior core. These diagonal members carry gravity load and lateral load by the axial action of the member. Due to the structural efficiency of diagrids, interior and corner columns can be avoided thereby providing flexibility in the floor plan. The diagrid structures are emerging as popular structural system in many developed countries of the world, but in India it is yet to gain importance. This paper presents a review on the literature of diagrid structures. Studies conducted on diagrid structures to determine the diagrid angle for the efficient design is presented. The stiffness-based methodology adopted for determining preliminary member sizes of steel diagrid structures and the effect of shear lag on high rise buildings with diagrid and its comparison with framed tube structures are discussed. The distribution of the load resisted by interior frame and diagrids is outlined. The parameters used in the comparison of analysis are time period, top storey displacement, inter-storey drift and storey shear. This paper also reviews the studies on the comparison of diagrids with regular configuration and diagrids with varying angles. The analysis and comparison of diagrid and conventional structural system on the basis of consumption of steel, structural weight and displacement are also highlighted. This review covers diagrids with all the materials in practice namely concrete, steel and concrete-filled steel tube(CFST).

Accurate description of creep crack stress field is very important to characterize the creep crack growth of the structures at elevated temperature. In general, the crack mode in practical engineering practices is not mere the mode I or mode II, and it is the mixed mode. The mismatch effect in weldment is also concerned by many researchers, however, there is no available literatures to discuss the stress field of mixed mode creep crack yet. The overall aim of this paper is to investigate and qualify the distribution of stress field for the mixed mode creep crack. In this paper, a mixed mode creep crack within the mismatched plate is discussed. The stress distribution of mixed mode creep crack are given in this article. With the definition of mode mixity for creep crack, the influence of mode mixity on the stress field is presented. The influence of mismatch effect on the principal stress, open stress and shear stress for mixed mode creep crack is also figured out. The main factor leads to the variation of creep crack tip stress field for mixed creep crack is analyzed. Some useful guidelines are proposed for the engineering purpose of integrity assessment for the structure at high temperature.

Primary water stress corrosion cracking (PWSCC) has been observed in CRDM nozzles, BMI nozzles and other penetration nozzles. The industry has used the repair method of replacement of nozzles fabricated of Alloy 690. After the replacement of the nozzle, the structural integrity analysis of new nozzle and welds should be performed to ensure the pressure boundary compliance with the original design requirement. In this paper, the pressurizer top head instrument nozzle of PWR nuclear power plant is evaluated as a typical pressure vessel penetration nozzle. The results showed that the repaired nozzle satisfies the ASME Code design requirement and the crack growth of the postulated flaw in 40 years of the nuclear plant life is acceptable.PWSCC degradation mechanism has been observed in CRDM nozzles, BMI nozzles and other penetration nozzles [1]. In some nuclear power plants built in China earlier, such as DAYABAY nuclear power plant and QINSHAN nuclear power plant, PWSCC degradation mechanism has been found in CRDM nozzle welds which manufactured of Alloy 600 and welded of Alloy 82/182[2]. The repair of the degraded nozzles is the popular choice for the nuclear power plant owners. After the replacement of the nozzle, the structural integrity analysis of new nozzle and welds should be performed to ensure the pressure boundary compliance with the original design requirement. In this paper, the pressurizer top head nozzle of PWR nuclear power plant is evaluated as a typical pressure vessel penetration nozzle. Stress intensities were conservatively determined for pressure and applicable thermal transients and compared to the allowable values of the ASME Code, Section III. Thermal stress of the transients was obtained from 3D finite element model (FEM). Residual stress of J-groove weld was obtained from 2D FEM analysis and used for fracture mechanics analysis. All of the analysis showed that the repaired nozzle satisfies the ASME Code design requirement and the crack growth of the postulated flaw in 40 years of the nuclear plant life is acceptable.

The strain-based failure assessment diagram (SB-FAD) has been developed to predict failure due to high plastic strains. This paper validates the SB-FAD by finite element results for high strength pipeline steel (X80, X80HD, and X90) with four representative specimens (CT, CCP, DECP, and SCEP) of different crack sizes, respectively. The influence of material properties, geometries and crack sizes on failure assessment curves were compared and analyzed. Meanwhile, the modified Option-1 curve of SB-FAD is given in this paper. The results showed that the modified Option-1 curve of SB-FAD is more accurate when the value of abscissais Dr small and more conservative when the value of abscissa Dr is large.

Creep crack within weldments are very common in engineering practices, and the cracking location in these welding structures always appears at the HAZ location. The mismatch effect on the mixed mode creep crack is still not clear in these available literatures. The aim of this paper is to investigate the mismatch influence on the creep crack of mixed mode thoroughly. A mixed mode creep crack within HAZ is established in this paper. The leading factor that dominates the creep crack tip field under mixed loading mode is studied. The influences of mismatch effect on mode mixity, stress distribution and stress triaxiality are proposed. The difference of mixed mode creep crack and normal mode I or mode II creep crack are compared. The influence of mixity factor on the transient and steady state creep of crack tip are also analyzed.

The structure of cylindrical shell with nozzle has been widely used in pressure equipment. The analysis and design for the structure of cylindrical shell with nozzle are generally based on the isotropy of metal at present, which may cause certain error and risk. Because of the approaches of rolling, heat treatment, and so on, the materials’ properties are different along each direction in practical engineering. In this paper, based on anisotropic thin shell theory, the analysis for orthotropic pressurized structure of thin-walled cylindrical shell with nozzle was conducted by using finite element software Ansys. The influences of thickness ratio and elastic modulus ratio were comprehensively considered, and also compared with the stress results under isotropic structure. The analysis results show that the values of stress and stress concentration factor for the structure of cylindrical shell with nozzle decrease with elastic modulus ratio, but increase with thickness ratio. Compared with the influence of thickness ratio, the elastic modulus ratio has significant effect on stress level. The rational use of the material anisotropic property can optimize the structure of thin-walled cylindrical shell with nozzle. The results in present paper provided a reference for the design of orthotropic pressurized structure of cylindrical shell with nozzle.

The convex tube sheet which is used in heat recovery boiler consists of three parts: the high temperature tube sheet, the low temperature tube sheet and the transition section.Three-dimensional finite element model of convex tube sheet in new type of heat recovery boiler is established in this paper. Using the ANSYS Workbench software, thermal stress of the convex tube sheet is analyzed. The temperature fields and thermal stress distribution of convex tube sheet are obtained, and its structure strength is checked. The effects of the high temperature tube sheet thickness, low temperature tube sheet thickness and transition section thickness on the maximum equivalent stress of the convex tube sheet are analyzed. The results show that: temperature of most parts of convex tube sheet is close to the tube side fluid temperature, and the large temperature gradient only existed in the thinner regions of shell side of convex tube sheet; temperature distribution shows obvious skin effect. At the transition section, the temperature along the thickness direction is more evenly distributed, with little change in temperature gradient; larger thermal stress mainly concentrated at tube layout area which close to the shell side of the high temperature tube sheet and the connecting parts of transition section and low temperature tube sheet in the tube side. Through checking the strength intensity, convex tube sheet structural strength meets the requirements.The transition section thickness are optimized. The optimum thickness of the transition section analyzed in this paper is 31mm.

To evaluate the fatigue damage accumulation and predict the residual life of components at different stress levels, this paper proposed a modified cumulative damage model based on the strain energy density parameter. Noting that mean stress and load interaction under uniaxial fatigue loading exhibit significant effects on fatigue damage accumulation and life prediction. According to this, a new model based on damaged stress model which considers the effects of mean stress and load interaction was presented in this paper. The proposed model was verified by using four experimental data sets of aluminium alloys and steels. The experimental results are compared with those of the Miner’s rule, damaged stress model (DSM) and damaged energy model (DEM). Results show that the proposed model agrees better with the experimental observations than others.

Uncertainty of parameters like material mechanical properties are traditionally described by probabilistic model, which requires detailed statistical information of parameters limited to obtain in engineering application. In this paper, the problem is solved by using the non-probabilistic convex model that only needs the upper and lower bounds of variables instead of abundant statistical information, which greatly reduces the demand of data and avoids unsafe results caused by the scatter of data. Based on the non-probabilistic convex model, the non-probabilistic interval analysis method is introduced to calculate the creep damage of HK40 high temperature furnace tube and to discuss the influence of operation conditions on creep damage with operation pressure and operation temperature regarded as interval variables. Consequently, the effect of outer wall temperature on creep damage interval is greater at the beginning of furnace tube operation stage. With the increase of running time, the effect of inner wall temperature on creep damage interval is greater and greater, and at the same time greater than that of creep damage interval when the outer wall temperature considered as interval variables. When the operating pressure is treated as interval variable, the upper and lower bounds of creep damage are nearly in a straight line that indicates the effect of pressure change on damage is little. Meanwhile, the life of high temperature furnace tube is predicted according to the definition of non-probabilistic interval index, and the analysis results are compared with the results of probabilistic model. The analysis results sufficiently demonstrate that the non-probabilistic approach presented in this paper is viable.

This paper takes a large supermarket as the research object. Based on its adding layer directly without identification, these implementations including reviewing design drawing, witnessed inspections, indoor test and theoretical analysis are carried. The identification results show that: the layer-adding design has a serious problem on the conception; part of the foundation's short concrete column misplaced seriously to its upper concrete column whose maximum is up to 50mm, and between the gap, there are some obvious weak positions existing some crossing pipelines which are filled completely with cement mortar; part of the concrete column's tails have serious phenomenon of cellular pits; the upper steel structure's support system is imperfect and unreasonable; the seismic capability of the blindly adding layer structure could not meet the national code's requirements. Based on the above structure defects, this paper ensure the safety of the adding layer structure through sticking steel's reinforcement method, section enlargement method and adding some structure 's support system.

This paper investigates the nonlinear dynamics and stability of the shallow von Mises truss, which is a prototype for buckling analysis of several planar and spatial truss systems and shallow lattice shell structures, including the geodesic dome, and which has a theoretical and practical interest in many engineering fields. These structural systems are liable to limit point instability and may fail at load levels well below the theoretical limit point load due to complex nonlinear phenomena that reduce the safety and the dynamic integrity of the structure; this often occurs as a consequence of the erosion of the basins of attraction of the safe pre-buckling solutions. So, it is vital to increase the safety of the structure in a dynamic environment. In this paper a method for controlling the global nonlinear dynamics of mechanical systems is applied to the shallow von Mises truss. The method consists of the (optimal) elimination of homoclinic intersection by properly adding superharmonic terms to a given harmonic excitation. By means of the solution of an appropriate optimization problem, it is possible to select the amplitudes and the phases of the added superharmonics in such a way that the manifolds distance is as large as possible. This methodology is here applied to increase the integrity of the basins of attraction of the system and consequently its practical safety.

Under the suspended crane loading, the key to the fatigue of the grid structure with bolt-sphere joints is the fatigue of the higher strength bolt. By now, there are not any research reports about the fatigue properties of M27 higher strength bolt at home and abroad. With the aid of the fatigue-testing machine and the loading device, this paper will have 8 constant amplitude fatigue experiments on test-piece, and will get the S-N curve of the higher strength bolt. With the aid of the metallographic analysis, this paper studies the mechanism and influencing factors of the fatigue failure; and with the aid of the finite element software ABQUAS, it analyzes and gets the stress concentration factor of the M27 higher strength bolt, and verifies the position of the fatigue failure.

Previous studies on the construction of lock-head allow to state that not only provide the means to reduce the stress, but more accurately reflect the actual force of the structure, which are given but there is no effect on the timing of the commissure analysis for the joint project.Based on the design of Xiangjiang River in Changsha integrated hub project, this paper propose the lock structure and layout of the program, in full consideration of the lock complex foundation condition, complex structure, temperature stress and other factors.In this paper, numerical simulation is used to simulate a variety of reasonable construction sequence and construction process, to analysis the characteristics of the stress of the bottom plate of the sluice, the settlement of the foundation and anti-force distribution features. And then discusses the overall stress characteristics and working mechanism of the first structure of the lower gate. On the basis of this, the reasonable construction sequence and structure optimization scheme are put forward.

The paper analyses the effect of Soil-Structure-Interaction (SSI) on the modal dynamic response of simply-supported span girder bridge with wall piers founded on caissons. A parametric analysis has been carried out in the hypothesis of linear elastic behaviour of all materials (soil and structure) to identify the influence of various design factors, such as the height of the pier, the caisson embedment below the ground level and the soil mechanical properties. The goal of the paper is to highlight SSI effects on the dynamic behaviour of bridges. This is a crucial aspect to be accounted for in order to support monitoring activities on bridges, aimed to structural identification or assessment of structure response under serviceability conditions, or also to have preliminary information for the seismic analysis of the bridge.

In some cases, due to particular conditions, the project of a bridge requires the construction of high piers. The study of these structural elements needs to go beyond a simple linear analysis, especially considering the second order effects, that contemplate the possibility of instability of the pier due to the slenderness it. In this paper a toolbox that considers the geometrical nonlinearity, the nonlinearity mechanical behaviour of the materials and the time dependent properties of the concrete is presented. The assessment of the pier starts with the possibility of cracking in the section (material non linearity) with consequent loses of stiffness. The second step takes into account the increment of bending moment caused by the P-d effect (geometrical non linearity) and strictly related to the slenderness of the member. The last step is the evaluation of the increment of deformation caused by permanent loads, mainly due to the loss of the concrete stiffness in time for creep effect of concrete. In this paper, a detailed explanation of the automatic procedure is provided and finally the application to a real case of a bridge pier under a critical stage construction condition is presented.

The collapse factor is a significant parameter in the framework of the safety assessment and economical design of ductile structures. This fact draws attention to the necessity of a careful assessment of the limit analysis approaches. The kinematics in these structures arises in fact from the actual rotation of the plastic hinges under axial force and bending moment. It can be shown that it is possible to obtain a reliable tool capable of competing with computationally expensive methodologies. The application of the methods of limit analysis involves a simplified and idealised model of the structure and, notwithstanding the fact that hundreds of papers have been devoted to the topic, some consequences of apparently unimportant simplifications still seem to have not been properly and firmly highlighted. This paper investigates the ultimate load and collapse modes of steel frames under combined vertical and horizontal forces through limit analysis.