Plastic Steel Research Articles

Plastic Constitutive Training Method for Steel Based on a Recurrent Neural Network

The deep learning steel plastic constitutive model training method was studied based on the recurrent neural network (RNN) model to improve the allocative efficiency of the deep learning steel plastic constitutive model and promote its application in practical engineering. Two linear hardening constitutive datasets of steel were constructed using the Gaussian stochastic process. The RNN, long short-term memory (LSTM), and gated recurrent unit (GRU) were used as models for training. The effects of the data pre-processing method, neural network structure, and training method on the model training were analyzed. The prediction ability of the model for different scale series and the corresponding data demand were evaluated. The results show that LSTM and the GRU are more suitable for stress–strain prediction. The marginal effect of the stacked neural network depth and number gradually decreases, and the hysteresis curve can be accurately predicted by a two-layer RNN. The optimal structure of the two models is A50-100 and B150-150. The prediction accuracy of the models increased with the decrease in batch size and the increase in training batch, and the training time also increased significantly. The decay learning rate method could balance the prediction accuracy and training time, and the optimal initial learning rate, batch size, and training batch were 0.001, 60, and 100, respectively. The deep learning plastic constitutive model based on the optimal parameters can accurately predict the hysteresis curve of steel, and the prediction abilities of the GRU are 6.13, 6.7, and 3.3 times those of LSTM in short, medium, and long sequences, respectively.

Design and mechanical response analysis of asphalt steel plastic pavement structure

In order to further study the mechanical properties of new asphalt steel plastic (ASP) pavement and explore optimal ASP pavement structures, this study analyzed the bottom tensile strain of asphalt mixture layer, the bottom tensile stress of steel plate layer, the bottom tensile stress of acrylonitrile butadiene styrene (ABS) layer, the top vertical compressive strain of subgrade and deflection. The results show that when the pavement structure adopts an 8 cm thick SMA layer, a 0.5 cm thick insulation layer, a 20 cm thick ABS layer, and 0.6 cm, 1.0 cm and 1.2 cm thick steel plate layers respectively, the mechanical properties of the ASP pavement are relatively good. The variation in the thickness of the steel plate layer has a greater impact on the bottom stress of steel plate layer. For the same pavement structure, when the dynamic load increases from 0.5 MPa to 0.9 MPa, the maximum values of the design indexes are linearly related to the dynamic load values. Under the static load, the shear stress generated in the steel plate layer is significantly lower than that in asphalt and ABS layers. The new asphalt steel plastic pavement has good mechanical properties and great application potential.

Mechanical response of asphalt steel plastic pavement structure based on finite element simulation and scale load test

To promote sustainable road engineering, the focus is on identifying low-carbon, eco-friendly, and durable materials and structures, as conventional options face performance limitations. Hence, within this paper, we introduce a novel pavement structure, referred to as ASP, which comprises an SMA-13 asphalt mixture, a Q345D steel plate, and acrylonitrile butadiene styrene (ABS) plastic. Initially, we performed a uniaxial compression test to analyze the dynamic mechanical properties and modulus parameters of both the SMA-13 asphalt mixture and ABS plastic. To further investigate the mechanical response of the ASP pavement structure under actual traffic load conditions, we constructed a 1/3-scale model and subjected it to MMLS3 accelerated loading tests to confirm the validity of the established finite element model and verify the performance of the structure. Finally, we developed a full-scale finite element simulation model of the ASP pavement structure and analyzed its mechanical response under loading. The results were then compared to those obtained from typical pavement structures. The results from the MMLS3 accelerated loading test show that both the asphalt and steel plate layers in the ASP pavement structure exhibit similar strain behavior, with consistent peak strains. The strain generated by the underlying structural layer dissipates more quickly in the transverse position, while the steel plate layer and underlying structural layer mainly support the strain generated by the asphalt surface layer. Results from the full-scale finite element simulations indicate that the strain and stress generated between the ASP pavement structure and typical pavement structures are similar. However, the bottom of the steel plate layer in the ASP pavement structure experiences significant three-dimensional and vertical shear stress. In addition, the allowable material value of the bearing layer in the ASP pavement structure, which consists of Q345D steel plate and ABS plastic, is less than 1% compared to the typical pavement structure. This characteristic enables effective transfer and support of the moving vehicle load, highlighting the significant advantages of using steel plate and plastic as pavement materials. To conclude, the ASP pavement's internal structure aligns effectively with real-world conditions, as demonstrated by its load-bearing layer's performance under vehicular loads. This innovative design significantly improves road durability and sustainability, positioning it as a choice for future road construction. These findings provide valuable insights for researching the mechanical response patterns within the ASP pavement's internal structure.

Test Rig for the In Situ Measurement of the Elastic Tooth Deflection of Plastic Gears

A new steel-plastic gear set testing methodology has been developed at the Institute of Polymer Technology (LKT). The in situ gear test rig analyses the timing differences between the index pulses of rotary encoders on the input and output shaft. This measurement principle enables the continuous measurement of the elastic tooth deflection on the one hand and permanent deformations and wear on the other hand by switching between a high loading torque and a low measuring torque. However, the elastic tooth deflection measurement using this principle has not yet been validated. Therefore, in situ gear tests using polybutylene terephthalate (PBT) gears were performed to evaluate the elastic tooth deflection of the plastic gear during operation. The results were compared to the results of pulsator tests. The comparison shows a very good correlation between the results of the newly developed in situ gear test rig and the well-established pulsator test rig. However, it has been shown that the test rig design creates a measuring offset due to angular displacements of the shafts due to torsion of test rig components.

Localization of plastic deformation during deformation of low‑carbon steel

When controlling the length of the yield site, the influence of the ferrite grain size, the amount of perlite, temperature, speed and deformation scheme on the localization of low‑carbon steel plastic deformation, which reduces the ability of the metal to deformation hardening, is considered.

Effect of Pipe Materials on Bacterial Community, Redox Reaction, and Functional Genes

In the present study, the effect of pipe materials on water quality as well as the microbial community was researched with static devices as well as dynamic ones. Five kinds of pipe materials (SP: steel plastic composite pipe, SS: stainless steel pipe, DI: ductile iron pipe, CI: cast iron pipe, GS: galvanized steel pipe) were chosen, and the soaking experiment was carried out with bench-scale devices. To further investigate the performance of pipe materials over a long term, a pilot-scale simulated drinking water distribution system was constructed, and the water quality parameters were monitored for six months. The pipe materials were ranked as SP, DI, and CI by the order of increasing turbidity, CODMn, and NH3-N. Furthermore, the biofilm samples were analyzed via pyrosequencing and COG functional categories. The DI biofilm possessed the highest bacterial diversity with a Shannon index of 3.56, followed by SP (3.14) and CI (0.77). The presence of nitrate-reducing bacteria (NRB), iron-oxidizing bacteria (IOB), iron-reducing bacteria (IRB), and sulfate-reducing bacteria (SRB)was identified, and NRB composed the largest share in all pipe materials (13.0%–17.2%), with other redox bacteria making up a minor proportion (0.02%–1.52%). NRB and IRB inhibited the corrosion process while IOB and SRB enhanced it. Most dominant genera present in samples were derived firstly from soil or active sludge, indicating a turbidity problem due to soil contamination in the distribution network.

Performance of Glass to Iron-based Shape Memory Alloy Adhesive Shear Joints with Different Geometry

Previous research has shown that glass beams with external, mechanical post-tensioning along their edges show better structural performance than glass beams without any such reinforcement. The initial and post-fracture load-bearing capacity of glass beams can be increased by reinforcing them with stainless steel or fiber-reinforced plastic (FRP) tendons that are post-tensioned and connected to the beam edges. However, post-tensioning of stainless steel or FRP bars or strips is complex and challenging because it often requires special setups, such as hydraulic jacks. Iron-based shape memory alloys (Fe-SMAs) are promising post-tensioning materials due to their efficient activation procedure and good mechanical properties. The target prestress level can be introduced by heating the Fe-SMA to a specific temperature followed by cooling down naturally to ambient temperature. As a contribution to assessing the feasibility of strengthening glass elements with adhesively bonded Fe-SMA strips, this paper focuses on the bond behavior of glass-to-Fe-SMA lap-shear joints based on numerical investigations. A finite element model is developed to evaluate the effect of adhesive thickness, Fe-SMA strip thickness and bond length on the structural behavior of glass to Fe-SMA lap-shear joints.

Mechanical Investigation of Carbon Steel under Strong Corrosion Effected by Corrosion Pits

This study investigated the effect of corrosion pits on the mechanical degradation of steel Q345 under strong acid corrosion. The experiment on a total of 27 steel Q345 specimens corroded by 36% industrial hydrochloric acid for 0 h, 1 h, 2 h, 4 h, 8 h, 12 h, 24 h, 48 h, and 72 h, respectively, is conducted to study failure mode and stress-strain curves. After that, a noncontact topography scanner (DSX500) scanned geometric parameters of corrosion pits in steel Q345 to establish its mechanical degradation. The surface morphology and the corresponding degradation law of corroded steel are also revealed. In addition, the steel plastic fracture criterion taking into account equivalent plastic fracture strain and average stress triaxiality T is adopted to propose the uniform pit model. The analysis results show that the failure mode gradually changes from ductile to brittle. It is noted that the depth and relative size of the corrosion pit are the main factors affecting the increase of the maximum pit coefficient. Further, FEM based on uniform corrosion pits is found by the flexible damage evolution criterion. Its calculation results are entirely consistent with experimental results, indicating that this model can mirror the surface morphology of steel suffering strong corrosion, and simulated accurately stress flow law and necking failure of strong corrosion steel. The proposed criterion is validated with verification results and can provide good references for the design of steel bridges under strong corrosion.

Microstructure-based finite-difference analysis of the plastic flow in low-carbon steel

Despite extensive research, the question – what makes the fronts of plastic strain (e.g. Lüders bands) propagate or remain still has not been solved yet. Therefore, the problem is acute for modern solid mechanics and physics. In this paper, an analysis of low-carbon steel plastic flow is carried out both numerically and experimentally. A microstructure-based finite-difference analysis is employed to provide a deeper insight into the emerging features of plastic flow. Low-carbon polycrystalline steel is chosen as the basic material for this investigation. A hand-controlled iterative procedure based on the step-by-step packing method is utilized to design a representative volume element (RVE) of the low-carbon steel under study. The designed model represents a cluster of grains randomly distributed within the computational domain according to a certain law and randomly oriented with respect to the global coordinate system based on the results of EBSD study. A number of earlier reported models of plastic flow are combined and modified to study the yield plateau stage of the model samples. The mathematical model parameters are accurately calibrated against the experimental data using quite simple methods. The results of modeling satisfactorily meet the available experimental data and sufficiently complement them in terms of reproducing some regularities of plastic flow observed both at micro- and macrolevel. Relying on the numerical modeling data the conditions at the front of the Lüders bands are discussed, which shed light on a possible mechanism of propagation.

Effect of Nitrogen Content on Solidification Behavior and Morphological Characteristics of the Precipitates in As-Cast 55Cr17Mo1VN Plastic Die Steel

Effect of Nitrogen Content on Solidification Behavior and Morphological Characteristics of the Precipitates in As-Cast 55Cr17Mo1VN Plastic Die Steel

Forecasting procedure for strength and ductile properties of alloy steel pipes in process of manufacturing and operation

Nowadays, the applicable scope of tubular products made of special steels is extended. Tubular products are used for new oil and gas fields development complicated by the presence of carbon dioxide and hydrogen sulfide. Further, pipes of corrosion-resistant and stainless steels are widely used in nuclear industry, aircraft engineering, at liquefied natural gas manufacturing plants and for other knowledge-intensive production branches. To ensure high-strength and corrosion-resistant properties of steel, a sufficiently large percentage of alloying elements, such as chromium, nickel, molybdenum and etc. are added into steel. However, these elements usually impair steel plastic properties in the process of pipe manufacturing by pressure treatment. Consequently, cracks and breaks may occur on hot-worked pipes. Therefore, the process of pipe manufacture engineering requires reliable information concerning ductility of steels used for pipe production.

Effect of Tempering Temperature on Microstructure and Corrosion Resistance of Plastic Mould Steel S136 SUP

Since the 21st century, the development of automotive and home appliance industries has greatly contributed to the prosperity of the plastics industry, which has led to an increasing demand for molding molds. In the production process, the molds will be impacted, worn and corroded, especially in the production of plastic products made of PVC, fluoroplastics and flame retardant ABS, etc. The molds will be corroded by the corrosive gases generated such as hydrogen chloride, hydrogen fluoride and sulfur dioxide, which requires plastic molds to have a certain degree of corrosion resistance while ensuring strong toughness.S136 SUP is a modified martensitic stainless steel based on S136 from ASSAB, Sweden, which has fine-tuned the content ratio of some elements to ensure a certain strength and high toughness at the same time. The chemical composition, heat treatment and microstructure of the steel have a certain influence on its corrosion resistance, and the tempering temperature of the heat treatment has a greater influence on the corrosion resistance of martensitic stainless steel. Therefore, in this paper, the microstructure and corrosion resistance of S136 SUP at different tempering temperatures are explored and studied.

Effect of Chases with Renovation Techniques on the Load Carrying Capacity of Masonry Walls

Infrastructure through the masonry walls (for example, wiring and piping works) are usually installed using chases in different directions. Introducing these chases in a newly built wall will affect its overall load carrying capacity. However, there has thus far been very limited research into the effects of chases on the response and load carrying capacity of walls. This study has been undertaken to evaluate the structural behaviour of new masonry walls having chases in both horizontal and vertical directions and subjected to compression load throughout an extensive experimental programme. In addition, two renovation techniques have been proposed to infill the chases created in small scale walls (wallettes). The first technique involved the use of plastic wire mesh and cement mortar, while the second incorporated using galvanized steel channel together with the plastic wire mesh and cement mortar. Furthermore, a reference case of wallette without chases has been considered to enable reasonable comparisons to check the effect of the chases and the efficiency of the proposed renovation techniques. The outcomes of this study were used to modify the design equations proposed in the relevant codes of practice. The obtained results showed a notable reduction in the load carrying capacity of the masonry wall due to the introduction of the chases with a reduction percentage of 29% compared to the masonry wall without chase. The percentage decrease depends on the depth of the chase and the inclination angle of the load flow. The walls with horizontal chases exhibited more reduction in the load carrying capacity compared to those with vertical chases. The adopted renovation techniques using galvanized steel channel and/or plastic wire mesh with cement mortar recovered 55% and 93% of the lost load carrying capacity due to the presence of the chase and the failure was due to the de-bonded phenomena of the infill materials. Suitable factors of safety have been proposed to be incorporated in the compressive strength and modulus of elasticity formulas of the masonry walls of the BS EN codes.

Risk factors for occurrence and abundance of Aedes aegypti and Aedes bromeliae at hotel compounds in Zanzibar

BackgroundA field survey was performed to investigate local environmental factors promoting occurrence and abundance of Aedes aegypti and Ae. bromeliae mosquitoes at hotel compounds in the south-east coastal region of Zanzibar Island.MethodsThe potential risk factors were determined using generalized linear mixed models. Aedes (Stegomyia) spp. indices such as container index (CI) and pupae per container (PPC) index were also estimated.ResultsAedes aegypti and Ae. bromeliae were the most abundant vector species, accounting for 70.8% of all Aedes mosquitoes collected. The highest CI was observed for plastic containers irrespective of the season, whereas the highest PPC was observed for coconut shells and aluminium containers in the rainy and dry seasons, respectively. The risk of Aedes mosquito occurrence and abundance were significantly associated with presence of plastic containers, coconut shells, used tyres and steel containers. These were discarded in shaded places, in the open and gardens, or found in plant nurseries.ConclusionThis study shows that Aedes species of global health significance occur at hotel compounds on this part of Zanzibar Island. The occurrence and abundance are sustained by the presence of abundant and poorly managed solid wastes and containers used for gardening tasks. This highlights an urgent need for the adoption of area-wide environmentally sustainable Aedes mosquito management interventions that also integrate solid waste management and ornamental plant production practices for reducing the risk of arboviral disease epidemics.Graphical

Experimental Study on Tensile Mechanical Properties and Reinforcement Ratio of Steel-Plastic Compound Geogrid-Reinforced Belt.

The steel–plastic compound geogrid has been widely used as a new reinforcement material in geotechnical engineering and other fields. Therefore, it is essential to fully understand the mechanical properties of steel–plastic compound geogrid-reinforced belts to utilize steel–plastic compound geogrids efficiently. In this study, tensile mechanical tests of steel wire, polyethylene geogrid belt, and steel–plastic compound geogrid-reinforced belt were conducted with respect to the tensile mechanical properties of steel–plastic compound geogrid-reinforced belts. In addition, the minimum reinforcement and optimal reinforcement ratios of steel–plastic compound geogrid-reinforced belts were summarized. The results showed that the steel–plastic compound geogrid-reinforced belts possessed an incongruent force of the internal steel wire during the tensile process. The tensile stress–strain curve of the steel–plastic compound geogrid-reinforced belt can be divided into the composite adjustment, steel wire breaking, and residual deformation stages. The tensile strength of the steel–plastic compound geogrid-reinforced belt is proportional to the diameter and number of steel wires in the reinforced belt. The minimum and optimum reinforcement ratios of steel wire in the steel–plastic compound geogrid-reinforced belt were 0.63% and 11.92%, respectively.

Design of a Novel Road Pavement Using Steel and Plastics to Enhance Performance, Durability and Construction Efficiency.

Durability is one important problem that pavement engineers need to address in pavement’s long service life. Furthermore, easily recycled pavement materials, and safe and efficient pavement construction are also important areas for development in road engineering. For these reasons, a new asphalt steel plastic (ASP) pavement structure was proposed with an asphalt mixture forming the surface layer, and steel plate and plastic materials functioning as the main load-bearing layers. Based on a comprehensive performance review and cost-benefit analysis, stone mastic asphalt (SMA) is recommended to be used as the surface layer; and A656 steel plate and acrylonitrile butadiene styrene (ABS) plastic materials should be the main load-bearing layer, on top of a foundation layer made with graded crushed stones. A glass fiber reinforced polymer (GFRP) insulation layer is recommended for use between the steel plate and ABS. Mechanical properties of the ASP pavement were analyzed using the finite element method. Laboratory tests were conducted to verify the thermal insulation performance of GFRP, the high-temperature stability and the fatigue resistance of ASP pavement. Results show that some of the mechanical properties of ASP pavement (with a structure of 80 mm SMA asphalt mixture, 8 mm steel plate, 140 mm ABS and 200 mm crushed stones) are comparable with conventional long-life pavement (with 350 mm asphalt layer overlaying 400 mm graded crushed stones). Dynamic stability of the ASP slab specimens can reach 10,000 times/mm, and the fatigue life is about twice that of SMA. Besides, the ASP pavement can be prefabricated and assembled on-site, and thus can greatly improve construction efficiency. From the lifecycle perspective, ASP pavement has many advantages over traditional pavements, such as durability, lower environmental footprint and recyclability, making it is worth further research.

Online media reveals a global problem of discarded containers as deadly traps for animals

The widespread occurrence of litter is a severe threat to global ecosystems. We have analyzed online media, to assess the diversity of animals that are prone to getting trapped in discarded containers and check which kind of containers is the most common trap for animals. A total of 503 records from around the world (51 countries, 6 continents) have been found. These include invertebrates (17 taxa, ca.1050 dead individuals), and vertebrates (98 taxa, 496 individuals including 44 carcasses). The latter group was most frequently represented by mammals (78.5% of all cases), then reptiles (15.3%), birds (1.2%), fish (1.0%) and amphibians (0.4%). Nearly 12.5% of the determined vertebrates are classified as vulnerable, endangered or critically endangered, according to the IUCN. Although most trapped individuals were smaller animals, bigger ones such as monitor lizards (Varanus spp.) or large carnivores were also recorded. In most cases, animals were trapped in glass or plastic jars (32.4%), drink cans (16.5%), and steel cans (16.3%). Our results demonstrate that discarded containers can be a threat to all major groups of animals. In order to address this phenomenon, it is necessary to decrease a global production of debris, implement container deposit legislation and organize repeatable cleanup actions.

Emission factor, relative ozone formation potential and relative carcinogenic risk assessment of VOCs emitted from manufacturing industries

Manufacturing industries are one of the important emission sectors of anthropogenic volatile organic compounds (VOCs). In this study, VOC emission factors, relative ozone formation potential (ROFP) and relative carcinogenic risk (RCR) were estimated for manufacturing industries (n = 13) located in central Taiwan. Emission samples were collected in stainless steel canisters and were analyzed with a system of gas chromatography-mass spectroscopy. Higher emission factors of total VOCs (∑VOCs) were observed for stencil printing (423 mg-VOC kg− 1) compared to other emission industries. Alkanes constituted the most prominent group of VOCs for steel foundry (42%), aluminum foundry (25%) and synthetic resin industries (25%). Oxygenated VOCs were the most abundant group in the organic solvent (80%), polyester resin (80%) and polyurethane (75%) industries. Moreover, emissions from acrylic resin manufacturing had a major contribution from aromatic compounds (> 95%). Toluene was the topmost compound in terms of its contribution to ∑VOCs in plastic tape manufacturing (44%), aluminum foundry (40%), steel foundry (12%), plastic coating (64%) and stencil printing (35%). Analysis of ozone formation potentials showed that the metal product and machinery acrylic resin manufacturing and stencil printing had a higher normalized relative ozone formation potential (ROFP) index and belonged to Level-I emission sources. However, in terms of the relative carcinogenic risk (RCR), integrated iron and steel manufacturing had the highest normalized RCR index that belonged to level-I emission sources. Level-I represents the most important VOC emission sources. This study provides a reactivity- and carcinogenicity-based approach to identify high-priority VOC emission sources. The results of this study would help formulate emission reduction policies and strategies for manufacturing industries.

A mirror with a scale- AR scalo mirror

The dental mouth mirror is one of the most common diagnostic instrument used in dentistry. This tool is small, cylindrical in shape, consisting of a metal/plastic bar as a handle and a metal/plastic plate as a mirror holder. The head of a dental mouth mirror is usually round and the most commonly used sizes are number 4 and number 5. The ruler used in dentistry is present either in the form of stainless steel bar or plastic rings. The ruler is used to measure the intraoral lesions, spaces between teeth in mouth or stone model, length of the tooth or implant in X-Ray, measure the length of files, paper tips and gutta-percha, etc. Therefore, AR Scalo Mirror is a combination of two dental instruments (mouth mirror and scale) which are put together as one so that it saves the time and effort as well as makes the diagnostic procedure less technique sensitive.

Stability analysis of integral load-bearing structure of surrounding rock of gob-side entry retention with flexible concrete formwork

According to the factors affecting the stability of the integral load-bearing structure of the surrounding rock of a retained gob-side entry, the load-bearing capacity of roadside supports with flexible concrete formwork is studied to propose a new integrated supporting control technology. This approach is based on a bolt and anchor cable support with a wire mesh for retaining the surrounding rock of a roadway. Moreover, the core of this technology involves roof bolts and steel beam supports with a steel–plastic wire mesh on the side of the gob beside the retained roadway, combined with the strengthening support of dual single props with upper and lower crossbars in the roadway. The roof-strata pre-stressed anchorage composite load-bearing structure, roadside flexible concrete formwork load-bearing structure, wire-mesh wall structure, solid coal wall load-bearing structure, and four-in-one load-bearing and stress-transferring control device in the retained roadway are formed in the surrounding rock of the retained roadway using integrated supporting control technology. Additionally, their supporting mechanisms are analyzed, and the corresponding construction technologies are clarified. Practical field results indicate that the integral load-bearing structure of the surrounding rock of the retained roadway formed by the integrated supporting control technology effectively controls the deformation and destruction of the surrounding rock, ensuring the success of the retaining roadway. Furthermore, dual gas channels are successfully constructed using this technology, thereby validating its efficient gas extraction.