Narrow Results

Owing to the superior mechanical performance, corrugated steel webs are extensively applied and their shear performance is critical, because of the thin wall. After the steel is corroded and the web is weakened, the problem of shear resistance may become more prominent. The shear performance of corrugated steel webs with local uniform loss was studied to simulate a common corrosion state. Twenty-eight FE models with different defect characteristics, containing defect height and web thickness, are established to simulate corroded corrugated webs. Shear capacity, shear strength, out-of-plane stiffness and bending stiffness are studied. Based on previous studies, the prediction formula is proposed to predict the residual shear strength. Additional FE models are built to validate the reliability. Results indicate that web thickness is the key factor to decide the deformation shape and shear capacity, compared with defect height. Bending stiffness decreases as defect increases. With 62.5% of the initial thickness, the influence of the variation of defect height on the bending stiffness is within 10%. Variation in thickness also affects the sensitivity of shear capacity to corrosion parameters and failure modes. When the thickness exceeds 1.25 mm, about 62.5% of the initial thickness, shear capacity is more sensitive to corrosion height than when the thickness is less than 1.25 mm. The proposed formula is validated and has a good agreement with the FE results, which could help to design the durability of corrugated steel webs and evaluate the performance of existing corrugated steel webs.

The horizontal press performance of column is deteriorated because of its special-shaped section. Moreover, because the antiseismic performance of column is worse, special-shaped column is only used in regions where seismic intensity is lower. So the main problem is to enhance the ductility and shear capacity. This test study on mechanical performance has been carried out through 14 SRCLSSC and 2 RCLSSC. The study focuses on the impacts of test axial load ratio (n_t), hooped reinforcement ratio (ρ_v), shear span ratio (λ) and steel ratio (ρ_ss) on the shear strength and the antiseismic performance of SRCLSSC. It can be concluded that the shear strength of SRCLSSC is increasing with the increasing of n_t and ρ_ss, but the degree of increasing is small when n_t is a certainty value, and that the shear strength of SRCLSSC is decreasing with increasing of λ; The shear resistance formula of L-shaped column is derived through tests, the calculated results are in correspondence with those of the tests. It also can be concluded that the hysteretic loops of the SRCLSSC are full and the hysteretic behaviors are improved; the displacement ductility is increasing with increasing of ρ_v and ρ_ss, but decreasing with the increasing of n_t; the degree of variety in high axial load ratio is larger than that in low axial load ratio. If steel bars are added, the shear strength and displacement ductility of SRCLSSC are increased in a large degree.

In this paper, high-nitrogen steel (HNS) was joined by vacuum brazing using an Ag–Cu–Ni filler metal and the effect of brazing temperature and duration time on the evolution of mechanical properties and microstructure of HNS joints were analyzed. The results showed that the optimal brazing temperature was 950${}^{\circ }$C and the optimal shear strength was obtained with the value of 212.4 MPa when the brazing temperature was 950${}^{\circ }$C with the brazing time of 10 min.

This paper discusses the various joining methods with faying surface modifications used to join AA6063 and AISI304L dissimilar alloys by Rotary Friction Welding (RFW) process at different welding conditions mainly with friction pressure (FP), upset pressure (UP) and friction time (FT). This paper also studies the tensile behavior of the welded joints. The fabricated dissimilar joints were tested using universal testing machine against tensile load, and the mechanical properties of all 30 nos. of weld joints like elongation (%), strength coefficient ($K$), strain hardening exponent ($n$), strain hardening rate (TS/YS ratio), shear strength, etc. were calculated from the tensile testing results and plotted here with a standard error bar. Hollomon’s equation is considered here to study the stress and strain hardening relation and Von Mises yield criterion is considered for shear and yield stress correlation. Total elongation is also calculated from the initial and final length obtained during the tensile test. Since fracture ductility of the joints depends on the stress, strain, ‘$K$’ and ‘$n$’ values, it is important to study these mechanical properties and how the tensile results can be used for their estimation is detailed in this paper. The faying surfaces influence the mechanical properties as well.

Cr coating on Zr-based fuel tubes is a potential approach for the development of accident tolerant fuels (ATF). To settle the cracking behavior and quantitative evaluation of shear strength of Cr coating under different loading conditions, the average shear strength between Cr coating and zircaloy substrate has been estimated using a modified shear-lag model in this paper. Its key parameters are determined experimentally, and the tensile method has been used to research the cracking behavior of Cr coating under different strain rates. The results show that with the increase of strain rate, the interfacial shear strength increases because of the decrease of cracking spacing, while the shear strength changes erratically with the coating thickness increases. Furthermore, abundant two unequal-crack-spacings and few two equal-crack-spacings are observed which are perpendicular to the loading direction.

Ag–26.7Cu–4.5Ti filler metals with different contents of SiC nanowires were prepared to analyze the effect of SiC nanowires on the microstructures, melting temperature, wettability, shear strength and fracture morphology of brazed joints. The results indicate that a small amount of SiC nanowires ($\le$0.1%) can refine the matrix microstructure and reduce the Cu–Ti intermetallic compounds, which can induce the increase of shear strength of brazed joints with 46.7% maximum amplitude, the ductile pattern is the main fracture mode for Ag–Cu–Ti–1.0 SiC brazed joints. Moreover, the SiC nanowires can improve the spreading are of Ag–Cu–Ti filler metals on steel substrate with a 9.4% increase amplitude, when the content of SiC nanowires is more than 0.1%, the wettability can be reduced obviously. The addition of SiC nanowires can show little effect on the melting temperature, which results in the same brazing temperature for Ag–Cu–Ti–$x$SiC filler metals. With the optimization content of SiC nanowires, the optimal content of SiC is 0.05–0.1%, excessive SiC addition with agglomeration can decrease the wettability and shear strength.

Compared without electroless Ni–P alloy coating on the SiCp/Al composites, the paper describes the effect of Ni–P deposited layer on the microstructure evolution, shear strength, airtightness and fracture behavior of vacuum brazed joints. Void free and compact reaction layers along the 6063Al/Ni–P deposited layer/filler metal interfaces indicated that the joints exhibit high airtightness with He-leakage less than $2.0\times 10^{-8}$ $\mathrm{\text{Pa}}\cdot {\mathrm{\text{m}}}^3/\mathrm{\text{s}}$. Energy Dispersive X-ray Spectroscopy (EDS) analysis showed that the reaction layers mainly included brittle Al–Ni and Al–Cu–Ni intermetallics, where fracture occurred in priority and the shear strength was less than 90 MPa. However, without Ni–P alloy coating, sound joints with high shear strength of 100.1 MPa but low airtightness with He-leakage higher than $1.45\times 10^{-7}\mathrm{\text{Pa}}\cdot {\mathrm{\text{m}}}^3/\mathrm{\text{s}}$ were also obtained at 590${}^{\circ }$C for soaking time of 30 min. In this case, a few holes that occurred along the filler metal/SiC particle interface significantly decreased the compactness of the joints. Therefore, according to the requirements in practical applications, suitable choice was provided in this research.

This paper deals with the shear strength of prestressed concrete box girders having corrugated steel webs (PCBGCSW), with particular emphasis on the shear lag and the stochastic variation of material properties. First, the shear strength curve of corrugated steel web is proposed based on experimental and analytical results obtained for simply supported beams composed of corrugated steel web without and with concrete flanges. In order to evaluate the shear strength of PCBGCSW based on the shear strength curve of corrugated steel web, it is important to know the distribution of shearing force between the corrugated steel web and the concrete flanges. The effect of the concrete flanges, therefore, on the distribution of shearing force is investigated considering the shear lag behavior. Finally the stochastic variation of material properties for the evaluation of the shear strength of corrugated steel webs is discussed from the design viewpoint.