An experimental study has been realized from plane and plate pressed structures, submitted to a real excitation like the one of a lawn mower engine. A quantitative vibroacoustic analysis (vibratory energies and acoustic power measurement, damping……), coupled to a qualitative analysis (binaural measurement and listening through an headphone, paired comparison tests,…..), have allowed to extract correlated parameters with preference scores.
Bioassays were carried out in Mar del Plata harbor (38°02’S-57°32’W). The series consisted of: i) control pipes (without copper) and pipes covered with saturated copper coating (A). A seamless carbon steel pipe of the kind habitually use in the oil industry was coated with 250-micron thick epoxy after heating at 200 °C, a second 300- micron thick layer of a polypropylene copolymer to function as adhesive between the epoxy and the third layer, which was about 60 mm thick and made of polypropylene with hollow glass microspheres. A 300- micron thick polypropylene film with necessary stabilizers was extruded onto this isolated pipe, and covered with 100 % copper powder (grain size 45-63 microns) on its entire surface, wich would be in contact with the sea water. The copper powder was thus strongly adhered to polypropylene to avoid its rubbing off due to abrasion. The second series included ii) control panels (without copper) and panels covered with
Assessment of old factory infrastructure is required in order to keep them working especially after natural hazard event such as earthquake, tornados, or variation of gravity loads. This type of structure is considered essential since it should be safety for workers during operation time and to avoid possible economical losses if this facility stops its operations after any main seismic event. It is presented the structural assessment of the infrastructure of a melt shop facility, which it used for production of structural steel shapes. This infrastructure was built at the beginning of 80’s and it is located at near Pisco city in Peru. Reinforced concrete C columns and L beams make the frames of the structure and the rood is made by steel trusts. NDT and destructive tests were made for the reinforced concrete members as well of extraction of steel coupons from the roof trusts. Auscultation of foundation, reinforced concrete and steelstructures were performed. It was found that several columns present damages such as spalling of cover, impact hits from heavy vehicles, which get in the interior of the facility. The roof presents metallic dust which was accumulated by the smelter operation. Heat of 50 Celsius degrees is the average temperature during the 20hours per day of operation time. Besides, capacity of several reinforced concrete columns and beams, and steel members of the roof is minor that their demands respectively according to Peru and international codes. The performance of the full structure of the melt shop including concrete and steelstructures presents allowed drifts according seismic provisions, however this structure behaves on its nonlinear range under demands of Peru seismic code.
In order to better understand how the mechanical properties of friction dampers affect the seismic response of steelstructures, a similar study with more consideration of the nonlinear behavior of the steel structure should be considered. Base structures similar to the ones considered in this study, but modeled considering inelastic behavior and other effects such as P-∆ or large deformations, may better determine if the observations found in this study still hold. A complementary study, or extension, of the previously described proposal might consider 3D models of the buildings. An extensive numerical analysis of such models might be computationally expensive, but based on the findings of this study, the range of values of the parameters of interest can be refined so that only the most re- levant cases are analyzed. Most important is probably the study of structures having a greater number of stories.
In the Netherlands new building concepts with removable inner walls, floors and installations are developed for multi-family houses. Lightweight, double structures as separating floors and walls and steelstructures are applied. In order to fulfil the noise requirements, it is necessary to restrict the sound transmission through cross-joints and steelstructures. For a future building, experimental set-ups of the cross-joints have been built (scale 1:1). Vibration reduction indices and other important parameters have been measured in these set-ups. In this paper the experimental set-ups and the measurement results are described. Based on the measurement results the airborne and impact sound insulation between houses is predicted. Another part of this research concerns the making of a FEM model of the cross-joints and is described in a separate paper.
In the Netherlands new building concepts with removable inner walls and installations are developed for multi-family houses. Lightweight, double structures as separating floors and walls and steelstructures are applied. In order to fulfil the noise requirements, it is necessary to restrict the sound transmission through cross-joints and steelstructures. For a future building a FEM model has been made of some cross-joints. Vibration reduction indices of these joints are calculated. This paper deals with the model and gives calculation results for several design variants of cross-joints.
The concrete and steel slabs have some constructive advantages in comparation with traditional systems. They offer a work platform during the structure’s execution, speed of construction, increase in local and global stability of steelstructures, height reduction in beams and self-weight reduction in structures (Craveiro, 2010; Liang, 2015). Although it is a highly used solution, the steel sensibility to fire require more attention in project (Li; Wang, 2013). The sensibility of steel materials to high temperatures grounds this discussion. In these composite slabs, the steel deck slenderness can promote failure in little time and sudden break (Li et.al., 2017).
Results of tensile strength tests on 16 mm diameter rebars are shown in Table II, where the data corresponding to the mechanical properties of the tested bars are supplied: yield strength (fy) and ultimate strength (fs). The level of corrosion reached in each one of the bars is expressed through variable C, representing the mass loss percentage (or section) of the bar regarding initial values, due to the corrosion process. Its values have been calculated gravimetrically, weighing bars after removing corrosion products, and assuming that the steel loss occurs evenly over the length of the corroded reinforcing bar. Mechanical characteristics have been obtained in relation to the equivalent section, calculated as the middle section of the bars after the corrosion process. This value has been gravimetrically calculated, weighing the bars after having eliminated the corrosion products and supposing the steel loss is produced in a uniform way over the length of the corroded bar. Table II shows the ultimate strength values (fs) for the bars with diameter 16, and the yield strength (fy)
DISCUSSION — It normally involves the addition of one or more austen- itic grain refining elements in amounts that have been established by the steel producer as being sufficient. Austenitic grain refining elements include, but are not limited to, aluminum, niobium (columbium), titanium, and vanadium.
Regarding the fracture of the specimens, with exception of specimens that showed welding defects such as lack of fusion or blowholes, the fracture were located at the plain carbon steel side of the samples. Figure 11A and figure 11B show the fracture surface of the specimens that failed under lower fracture stress than the stress of the other specimens with the same preparation. The influence of these defects in the mechanical behavior of these specimens is proved by the fact that welding defects are revealed on the fracture surface of the specimens. For instance, figure 11A the fracture surface of the single bevel specimen with buttering. A lack of fusion on the fracture is the origin of the fracture. This is proved by the river marks indicated with black arrows. These results agree with the work of Jang et al. They showed that the fracture of dissimilar welded joints using Inconel as filler metal strongly depend on the weld (Jang, C., Lee, J., Kim, J. S., & Jin, T. E. 2008).
Many researchers, for instance Brown (1976), Treadaway (1989), Sorensen (1990), Nurnberger (1996) McDonald (1998), Pedeferri (1997), Bertolini (1998), and Baltazar (2007), have carried out studies to evaluate the behavior of stainless steel as reinforcement material for concrete structures. On the other hand, Lundin, (1982), Doddy, (1992), Ospina, (2007), García (2011), and Pérez-Quiroz (2016) have researched the metallurgy and mechanical properties of dissimilar welded joints, and their results demonstrated that the application of these joints is feasible for refurbishing concrete structures. Considering that stainless steel is more expensive than carbon steel, carbon and stainless-steel reinforcement bars can be joined by connectors or weld joints to improve the corrosion resistance of a concrete structure and reduce costs.
Now, the structures in (11) correspond to main clauses in German which have, as is well known, V2 status. They thus differ from the English structures in (10) above not only in the OV order, which is now irrelevant, but also in the fact that the finite auxiliary haben ‘have’ occupies the C position, and the DP complement of the stranded quantifier (as in (11b)) occupies the Spec,C position, rather than Spec,T: see (11b´). Precisely because the eventual positions of internal merge (or movement) in this small paradigm are Spec,C and C, the movement of the DP complement away from the quantifier in (11b) does not contradict any possible operation of vP-pied piping, since such an operation could in any case have applied prior to the movement of DP to Spec,C. That is, in accord with a vP-pied piping account, before the movement to the C projection, the chunk or portion [SOV] alle die Studenten das Buch gelesen would have moved to the Spec,T position, which is actually the very vP-pied piping configuration, and the auxiliary haben would have moved to T. Subsequently, the auxiliary moves to C, and the complement of the quantifier moves to Spec,C.
La siguiente obra muestra las espectaculares posibilidades del steel framing. Se trata del estrado utilizado para la beatificación de d. Alvaro del Portillo que tuvo lugar en Madrid en septiembre de 2014. El estrado, al ser una estructura efímera se había planteado inicialmente para su resolución mediante mecanotu- bo, sin embargo la apariencia estética provocó muchos recelos lo que abrió la vía a buscar nuevas soluciones estructurales planteándose la estructura median- te el sistema LGSF.
The adhesion was better in the duplex sample than in the coated sample. This could be due to the difference between the elastic moduli. This difference is smaller between the coating and the nitrided layer than between the coating and the stainless steel. Consequently the stress gradient is lower, and the coating was not detached in the duplex sample. On the other hand, during the annealing, thermal stresses are induced. Probably, these stresses were higher in the coated sample than in the duplex sample because of the presence of the silicon layer (with thermal coefficient similar to DLC) and the precipitation of second phases such as
A special case of structures with bounded FO types is any recursive class of structures with a unary vocabulary. Note that in these structures the relations are sets. We can build formulae which isolate the FO types for elements in a given structure considering how each element participates in the different sets. Using this formulae we can build formulae which isolate the FO type for k-tuples in a given structure. It is interesting to see that, fixing a unary vocabulary, there is a finite set of intra-isolating formulae for FO types for k-tuples.
La construction de structures 3D avec l’assemblage d’éléments 2D très fins est présente depuis le début de l’histoire de l’humanité, une de ses applications les plus connues et anciennes est la construction de vêtements avec des tissus découpes convenablement. Bien que celle -ci soit l’application la plus développée de ces méthodes, nous allons orienter la démarche à des structures gonflables qui sont caractérisés par être des surfaces fermées, différence principale avec les vêtements.
begins from degradation symptom appearance (e.g. cracks > 0.1 mm in width; concrete spalling; visible loss of steel section, etc.) and ends with structural collapse. During this final stage, load capacity progressively degrades in the corroding structure (Troconis de Rincón y col., 1997). In other words, the residual life can be considered as the time during which a structure must be repaired before collapsing.
The specifi c wear rates in specimens of the diﬀ erent coatings and substrates are shown in fi gure 6. In the case of TiN, the steel that presented greatest wear was 4320 steel with a load of 7.84 N, then the 8620 steel with 7.84 N and after that the 4140 steel for a load of 11.76 N. The smallest wear rate was with 8620 steel (11.76 N). The behaviour of the wear-load relationship for steels 4320 and 8620 was in agreement with expectations, i.e. higher load, greater wear. This also explains why on the load-friction coeﬃ cient relationship, there was greater detachment of the coating, but the coeﬃ cients of fric- tion were lower. For the CrN coating, it was more diﬃ - cult measure the wear volume to determine the wear rates, because the irregular form of the scar, it was used the average of the scars from the roughness profi les (fi - gure 5). The greatest specifi c wear rate happened in the 4140 steel (11.76 N), and the lowest value was presented in the 4320 steel (7.84 N). For the WC/C coating, the wear was greater in the balls than in the coating (fi gures 6 and 7), due in part to the low coeﬃ cient of friction. In general, the wear rates in the specimens were similar in all substrates and types of load. The wear rates of subs-
In part a) of Figure 3 it can be seen the wear mecha- nisms on bare steel and the spherical counterpart bone. There are two wear mechanisms: abrasive wear and ad- hesive wear. Second zoom shows plow lines indicating abrasive wear likely because of some steel particle came off due to fatigue and strain hardened generated abra- sion to disk. The zoom shows bone adhesion to the disk; it is also observed that adhered material fractures because of fatigue forming wear debris acting as a third body. In part b) we observe wear mechanisms of coated steel. Abrasive wear is not observed and EDX probe re- vealed no bare steel, so it follows that the coating main- tained its integrity after testing. The only wear mecha- nism observed is adhesive and fatigue fracture of bon- ded bone forming wear particles. Figure 4 shows the wear mechanisms of bare steel and coated steel in Hank’s solution. It can be seen that the only wear me- chanisms both cases is bone adhesion, there is no abra- sive wear in neither case, there is no detachment of the coating, and there is salts precipitations.
If operations similar to tose described above were conducted, a table of values could be built for the new parameter defined by Creazza. Table 2 gives such results for one steel with a yield strength of 500 N/mm 2 and no definite yield point. Despite the enormous scientific and technical interest of the two criteria equivalent steel discussed in the preceding paragraphs, they have two serious drawbacks .