Plastic Design Research Articles

Studi Kinerja Struktur Beton Bertulang Beraturan Yang Didisain Dengan Performance Based Plastic Design

Indonesia is a country that has a very high level of seismicity. It is necessary to plan a building structure that can withstand the earthquake load. Indonesia has adopted guidelines on earthquake resistance planning procedures for buildings and non-buildings. This guideline uses the Performance-Based Seismic Design (PBSD) concept. Performance-Based Plastic Design (PBPD) is a structural analysis with the concept of energy methods which was initially used on steel structures. For reinforced concrete structures this method can also be used using the C2 coefficient. To determine the performance level of structures designed using the Performance-Based Plastic Design method, an analysis of the five-story reinforced concrete structure was carried out. Next, the structure will be analyzed using pushover loads. From the structural performance analysis, the structural ductility value based on Performance-Based Plastic Design (PBPD) was 3.014. The performance level is based on the capacity spectrum at the immediate occupancy level.

Review of Design and Production of the Injection Moulding Machine

Plastics are being employed for both light and heavy items in industrial settings more and more often. Plastic daily objects like bottle caps, remote control casings, needles, and more are created using injection molding equipment, along with large goods like automotive body panels. During the molding process, a liquid or flexible raw material is shaped using a rigid structure known as a mold. This technique originally became popular during the Second World War as the need for mass-produced items increased. It is now extensively utilized across various industries. This study examined the role of plastic molding machines in the design and production of these devices. To correctly examine the corpus of knowledge about the design and production of plastic molding machines, this was done by comparing and assessing already published, widely available works, beginning with early innovations and continuing with more recent advancements. The study's objective was met. Despite rising efforts to design and construct more modern machines that are economical and compact, it was noticed that the bulk of early injection molding machines were large. The injector molding machine has the potential for further improvement and local manufacture, according to the study's conclusions.

The Modified Energy-based Method for Seismic Evaluation of Structural Systems with Different Hardening Ratios and Deterioration Hysteresis Models

Prediction of target displacement in structural systems plays a significant role in performance-based design and rehabilitation of structures. In this study, the γ factor for different hardening ratios, including 1, 2, 3, 5, 7.5, 10, and 15 percentages, stiffness-strength-deterioration models, and soil type classes is determined to modify the energy balance equation in performance-based plastic design (PBPD). Statistical results indicate that the effect of the hardening ratio, deterioration, and soil type class on the capacity curve is considerable. Therefore, a simple equation based on the period of the vibration and ductility is suggested to estimate the γ factor in different structural systems. Moreover, four 1-, 3-, 7-, and 12-story moment steel structures with various hardening ratios in the material are designed to validate the proposed method. The suggested values for the γ factor show exact results compared to collected displacements from time history analysis, while the error in the previous work was considerable. Statistical results showed that the mean error in the previous method in estimating target displacement for 1-, 3-. 7-, and 12-story structures is about 15%, 20%, 20%, and 32%, respectively. Conversely, the mean error in this study for estimating target displacement of 1-, 3-. 7-, and 12-story structures is about 10%, 7%, 6%, and 15%, respectively. Finally, the proposed method is examined on the empirical reinforced concrete (RC) bridge pier simulated numerically with fiber-based modeling. Similarly, the suggested equation estimates the target displacement appropriately for the concrete model compared to achieved displacements from nonlinear dynamic analysis.

Seismic vulnerability of shield tunnels in interbedded soil deposits: Case study of submarine tunnel in Shantou Bay

This paper presents a numerical approach for deriving seismic fragility curves for a submarine shield tunnel subjected to transverse ground shaking in interbedded soil deposits. To simulate the nonlinear behavior of soils, PM4Sand and HS-small constitutive models were adopted. In contrast, the closed-form elastic design method or elastic–plastic design method was used for modeling the shield tunnel lining considering the effect of joints on the seismic performance of structures. Fully coupled numerical analyses provided a satisfactory interpretation of the seismic responses of soil–structure systems considering the effects of groundwater level and soil–tunnel interaction. Subsequently, free-field peak ground acceleration was selected as the intensity measure. The ratio of maximum bending moment to capacity bending moment or permanent joint rotation of the tunnel lining was selected as the damage measure, combined with incremental dynamic analysis, a series of fragility curves were generated. In this study, one-dimensional equivalent-linear earthquake site response analysis was implemented to validate the nonlinear dynamic analysis under weak earthquakes. However, the analysis overestimates the amplitude periodic vibrations in interbedded soil deposits under strong earthquakes. Additionally, numerical results show that the examined tunnel is prone to slight or moderate damage under ground shaking, and its joints are more vulnerable to damage than its segments. The fragility curves constructed were compared with existing fragility curves, highlighting the significant effects of local soil profiles, groundwater conditions, soil–tunnel interaction, and segmental joints on the seismic vulnerability of shield tunnels in a submarine environment. The developed fragility functions contribute to the prediction of seismic damage to submarine shield tunnels of similar characteristics, enabling the rapid and efficient response of structures to disasters in ocean engineering.

FDM 3D PRINTING AS AN ALTERNATIVE FORM OF MAKING PATTERN FOR METAL CASTING: A COMPARISON WITH WOOD-BASED PATTERN

The problem with the wood-based design is that it changes size when it absorbs water, which can make the pattern grow and shrink, and the surface goes away, making it unsuitable for mass production. Plastic is the most common 3D printing raw material, and it can be used to build practically any form of object. Fused Deposition Modelling (FDM) is a type of 3D printing prototyping that may be used to make a plastic design for metal casting. In this project, the metal casting product were evaluated by casting quality and surface roughness for both 3D printed- based pattern and wood-based pattern. For the quality of their castings, both generate the same shape based on the dimensions specified by their respective patterns, but both have experienced gas porosity. For the surface roughness produced from the wood-based pattern, an average Ra value of 1.965 micrometres was recorded, while the average Ra value recorded from the 3D Printed-based pattern was 2.357 micrometres. The findings revealed that wood-based pattern produces a slightly better surface than 3D Printed-based pattern, but 3D Printed is still relevant to be used as a pattern because it is more durable and easier to produce with good time consuming.

Theoretical and Numerical Studies of Elastic Buckling and Load Resistance of a Shuttle-Shaped Double-Restrained Buckling-Restrained Brace

A new type of shuttle-shaped double-restrained buckling-restrained brace (SDR-BRB) is proposed, which adopts the form of a shuttle-shaped deformation section similar to its bending moment distribution as the external restraining system. The SDR-BRB has the advantages of superlong size, high load-carrying capacity, and lightweight components, and is suitable for use in large-span spatial structures and bridge structures with an exposed BRB. First, the calculation formula of the elastic buckling load of a pin-ended SDR-BRB is derived based on the equilibrium method, which is verified through the eigenvalue buckling analysis method, and the effects of the main geometric parameters on its elastic buckling behavior are evaluated. The effects of multiple key factors on the load-carrying capacity of the SDR-BRB are then studied by parametric analysis. The results show that the restraining ratio, initial imperfection, and gap have significant effects on the ultimate load-carrying capacity and overall stability of the SDR-BRB, while the effect of the diameter–thickness ratio is relatively small. On this basis, the fitting formula of the critical restraining ratio of the SDR-BRB considering the influences of initial imperfection and gap is proposed and verified by finite element analysis. The research lays a foundation for further research into the elastic–plastic hysteretic behavior and design method of an SDR-BRB.

The Plastic Elements in the Technical Design of the Linear Formations in the Kiswah of the Kaaba: An Analytical Study

The art of Arabic calligraphy with its artistic and plastic elements and vocabulary has a key role in highlighting the aesthetics of the covering of the Kaaba, in addition to the fact that all the plastic elements in the design of the structure of the linear formations result from the organization of linear relationships on the surface of the covering fabric, which are intertwined and intertwined in all formations and linear structures in the dress of the Kaaba. Therefore, this study aims to analyse the aesthetic relationships between the linear structural elements and the plastic artistic elements present in the design of the covering of the Kaaba according to an analytical artistic vision. The method used in this study is the content analysis method, which is an applied field study based on a careful and detailed analysis of the compositional, plastic and design elements within the dress of the Kaaba. The study concluded that the linear and artistic plastic elements had a prominent role in enhancing the aesthetics of the covering of the Kaaba. Islamic Art and Heritage. Keywords: plastic elements, artistic design, calligraphic formations, the covering of the Kaaba, Islamic art

Seismic design of buckling-restrained knee-braced frames considering cumulative damage

A buckling-restrained knee-braced frame (BRKBF) is an efficient structural system utilizing short buckling-restrained braces (BRBs) as knee bracing elements. Because of the shorter yielding core length compared to those of conventional BRBs, one of the key parameters concerning the performance of this system is the low cycle fatigue cumulative damage of the BRBs. This paper presents a seismic design method considering the cumulative damage, performance evaluation, and collapse assessment of 3-story, 6-story, and 9-story archetype BRKBFs. An energy-based plastic design method was utilized to design the example frames. The frames were then evaluated by nonlinear static analysis and multiple-stripe analysis (MSA). The results indicated that BRKBs were able to accommodate seismic motions with limited damage. The validity of the design methodology considering cumulative damage was also confirmed.

Adaptive topology optimization of fail-safe truss structures

Avoidance of disproportionate and progressive collapse, often termed ‘fail-safe design’, is a key consideration in the design of buildings and infrastructure. This paper addresses the problem of fail-safe truss topology optimization in the setting of plastic design, where damage is defined as a moveable circular region in which members are considered to have zero strength for that particular load case. A rigorous and computationally efficient iterative solution strategy is employed in both the dual (member adding) and primal (damage-case adding) problems simultaneously, which allows cases of high complexity and many damage cases (maximum of 16290 potential members and 16291 damage cases) to be solved to the global optimum. Common member-based damage definitions (e.g. damage to any one member) are shown to be highly dependent on the nodal grid; in the limiting case completely negating the effect of the fail-safe constraints. The method proposed in this article does not have such limitations, enabling a more sophisticated and robust treatment of fail-safe design. Moreover, the global minimization and high resolutions create new benchmarks for the least-material designs of ‘fail-safe’ structures using rigid-plastic materials. A number of example structures are considered (short cantilever, square cantilever, multi-span truss), and the effects of damage radius, location, and structure rationalisation are discussed.

Seismic performance of eccentrically braced precast reinforced concrete columns-steel beams frame with replaceable shear links based on plastic design

To promote the seismic performance of reinforced concrete column-steel beam (RCS) frame, eccentric braces were creatively introduced into it. An improved plastic design method considering the differences in the combination of concrete and steel was proposed for the structure. The plastic design method not only adopts the energy-balance criterion considering the pinch effect of the concrete column and the influence of damping to accurately determine the base shear force but also considers the reasonable value of the story shear distributions along the height and the shear-sharing ratio between MRF and EBF substructures in detail. By considering cases with different heights, this paper verifies the effectiveness of the proposed method with a refined finite element model based on Sap2000. Meanwhile, a case based on the elastic design method was also presented for comparison. To prove its practicability in real engineering, the results of extensive nonlinear static and dynamic analyses of the 6-story and 9-story frames were conducted in terms of base shear, yield mechanisms, link plastic rotations, and inter-story drifts. The results show that the elastoplastic base shear and yield mechanisms predicted by the plastic design method have an acceptable agreement with the numerical simulation results under nonlinear analysis conditions. In addition, average inter-story drifts obtained by the nonlinear time history analysis met the calculation expectation, and the distribution coefficient adopted in this paper has good applicability to the eccentrically braced RCS frames, demonstrating that the structural elastoplastic response could be controlled by the proposed design procedure.

Preface to the special issue: biotechnology of plastic waste degradation and valorization

Synthetic plastics have been widely used in various fields of the national economy and are the pillar industry. However, irregular production, plastic product use, and plastic waste piling have caused long-term accumulation in the environment, contributing considerably to the global solid waste stream and environmental plastic pollution, which has become a global problem to be solved. Biodegradation has recently emerged as a viable disposal method for a circular plastic economy and has become a thriving research area. In recent years, important breakthroughs have been made in the screening, isolation, and identification of plastic-degrading microorganisms/enzyme resources and their further engineering, which provide new ideas and solutions for treating microplastics in the environment and the closed-loop bio-recycling of waste plastics. On the other hand, the use of microorganisms (pure cultures or consortia) to further transform different plastic degradants into biodegradable plastics and other compounds with high added value is of great significance, promoting the development of a plastic recycling economy and reducing the carbon emission of plastics in their life cycle. We edited a Special Issue on the topic of "Biotechnology of Plastic Waste Degradation and Valorization", focusing on the researches progress in three aspects: Mining microbial and enzyme resources for plastic biodegradation, Design and engineering of plastic depolymerase, and biological high-value transformation of plastic degradants. In total, 16 papers have been collected in this issue including reviews, comments, and research articles, which provide reference and guidance for further development of plastic waste degradation and valorization biotechnology.

Optimal Plastic Reliable Design of Reinforced Concrete Beams Considering Steel Bars Volume Probability

This paper aims to investigate the plastic response of reinforced concrete tapered beams when subjected to random steel reinforcement volumes, using both deterministic and probabilistic analyses, with the complementary strain energy as a boundary in the first case, and the reliability index as a boundary in the second. The first step in this study was to use a previously studied model and perform a deterministic analysis, assuming that the complementary strain energy is a limiting factor and controller of the plastic behaviour. Next, a probabilistic analysis is applied, with the reliability index as a limitation. At the same time, the volume of the reinforcement steel used, and the complementary strain energy were treated as probabilistic variables with mean values and specific standard deviations. This novel method highlighted the plastic behaviour limiting procedure and provided results that highlighted the nature of the model’s changed behaviour when the complementary strain energy was controlled and when applying probabilistic properties with reliability index limitation.

Plastic design of sustainable steel earthquake resistant structures

Earthquakes induce ultimate load conditions in most earthquake resistant structures and often lead to complete failure and disposal. Seismic sustainability is a limit state condition with a view to revival, reuse, and environmental protection. In the present context, sustainable seismic design implies planning for controlled energy dissipation, sequential failures, collapse prevention, construction economy and post-earthquake realignment and repairs. However, regardless of savings and environmental improvements unless an earthquake resistant structure is designed for the purpose, it would be disposable with greater monetary loss and harm to the environment. It has been found that steel mixed multiple seismic systems are well-suited for sustainable seismic design. Mixed multiple structures are combinations of two or more low/controlled damage ductile structures, an articulated gravity frame, a collapse preventive, hybrid, rigid rocking core, and a phantom P-delta system acting together to form a repairable archetype. Each earthquake resistant system is equipped with replaceable energy dissipating and fail-safe devices. Such arrangements call for applications of Plastic Design and Performance Control principles, rather than conventional methods of approach. This in turn calls for development of modern design rules, technologies and details that govern the behavior of such systems equipped with replaceable energy dissipating devices. In the interim several observations that reduce the task of otherwise cumbersome analysis to simple rules of response have been introduced.

Seismic performance evaluation and design of resilient knee braced frames equipped with shape memory alloy knee braces and replaceable energy-dissipating connections

This paper proposes a novel seismic resilient knee braced frame (KBF) and focuses on seismic performance evaluation and design. In this novel system, the shape memory alloy (SMA) knee braces (KBs) and replaceable energy-dissipating (RED) connections are the key components. The SMA KBs mainly provide self-centering capacity, and the RED connections mainly offer energy-dissipating capacity. To reveal the seismic performance characteristics, the 3- and 6- story KBFs are selected as the example structures. The proposed systems are designed by a modified performance-based plastic design method, which distributes the seismic energy to the SMA KBs and the RED connections by defining an energy distribution factor p. In what followed, nonlinear static and nonlinear time history analysis are conducted. It indicates that these systems could well meet the prescribed performance targets, although they are designed using different p values. In current work, the potentially optimal p value is found to be 0.1, which represents the case where 10% of seismic energy is allocated to the SMA KBs. The advantages of the novel KBF are twofold: 1) the consumption of SMA material is significantly reduced, because the RED connections are the major damping source; 2) the damaged RED connections can be conveniently repaired or replaced, because the frames could nearly return to original position, owing to the SMA KBs.

Seismic design of hybrid braced frames with self-centering braces and fluid viscous damping braces

Combining self-centering braces (SCBs) and fluid viscous damping braces (FVDBs) in parallel emerges as a promising seismic-resistant strategy, because it has the potential of simultaneously controlling peak deformation, peak acceleration, peak base shear and nearly eliminating residual deformation. However, the corresponding seismic design method is still under development. To this end, this paper extended the performance-based plastic design (PBPD) method to hybrid braced frames (HBFs) equipped with SCBs and FVDBs. The PBPD method selected target drift and yield mechanism at the very beginning of the design procedure, and then it derived the design base shear using energy equivalent concept. The key step was to obtain the constant-ductility spectra of the equivalent single-degree-of-freedom systems through nonlinear time history analysis (NLTHA). The regression functions of the spectra were then incorporated with the PBPD procedure. A six-story steel frame was selected for demonstrating the design method. A total of 4 HBFs were designed by defining 4 levels of viscous damping ratio (ξv) supplemented by FVDBs. The seismic responses of the designed HBFs were examined by subjecting them to 20 earthquake ground motions. The NLTHA results indicated that the designed HBFs can well satisfy the performance targets. The design method was robust, although the ξv values were varied in a wide range. The design method may also shed light to the other types of hybrid systems with displacement- and velocity- dependent damping braces.

High-performance grout-reinforced shear connectors for hybrid steel-cross-laminated timber building systems: Experimental study

Wood-based construction advancements have been observed recently with the adoption of hybrid assembly and offsite construction methods, relying on prefabricated components, such as volumetric cross-laminated timber (CLT) modules or composite panel-type wall and floor elements. Within the high-rise timber building framework, mass timber structural assembly requires connections designed to accommodate innovative technologies to limit damage under seismic loads and mitigate lateral vibration of the building under serviceability loads. As part of the performance-based capacity and constructability enhancements, current research efforts have been on the development of high-performance and reliable mass timber connections. This paper presents a new connection design method for hybrid steel-CLT composites and assemblies. Shear connectors are fabricated by encasing steel rods into CLT panels using an epoxy-based grout, with geometry specified to provide stiffness and shear capacity target levels. An insight into their behaviour and performance is given based on an experimental dataset comprising 240 full-scale push-out shear tests and an array of rod diameter, grout thickness, and mechanical properties of steel and CLT. Maximum shear strength of 289.6 kN and elastic stiffness of 243.2 kN/mm were attained for the tested specimens, showing that strong and stiff behaviour were attainable. Elastic mechanical properties of connectors were shown to be governed by the rod diameter, whereas strength resistance and failure mode from the grout thickness, allowing for decoupling of design parameters and fine-tuned design. The yield point was shown clearly identifiable, supporting optimum capacity design strategies. Observed failure modes were mostly ductile and with a maximum slip ductility of 6.4, and on average comparable with common wood bolted connections. A resistance factor of 0.8 was shown adequate to design the shear connectors using the calculated 5th percentile values of the yield shear resistance and maximum shear resistance, relatively, for elastic and plastic design strategies. Large-scale building applications were shown attainable by intrinsic individual mechanical properties of the connector, supporting deconstruction and reuse of the hybrid steel-timber structural system components when the connector is capacity-protected and behaves elastically; thus, designed using its 5th percentile yield shear strength.

Plastic design and strength on automotive hard trims doghouse

Trims are the plastic parts installed on the inside and outside of a car. Interior trims are typically used to give the interior of a vehicle an aesthetic appearance.There are various types of trims used in automobiles. The door's inner mechanisms and the vehicle's interior are connected by the door panel, as are the passengers inside the car and the door. They must adhere to a number of design requirements in terms of functionality, appearance, and safety. They should also maintain the dashboard's material theme while hiding complex electrical and mechanical parts that control the vehicle's locks, windows, and other features. From a straightforward latch and winding mechanism in two parts, the door panel has developed into a more complex enclosure. Currently, doors have an inner full-width panel with speakers, electronic windows, and a central locking system. These panels typically have a foamed core that is covered in either plastic or textiles. Trim manufacturing requires a lot of essential plastic material properties, such as restraining the passengers from the sharp edges and corner points of the BIW parts and underlying components.

DEFORMATION CAPACITY AND DUCTILITY OF SHEAR CONNECTORS

AbstractDeformation capacity and slip range (eventually called “ductility”) of shear connectors are key parameters for the design of shear connectors in composite beams, especially in partial shear connection. Existing design rules require a deformation capacity of at least 6 mm for the use of shear connectors with plastic design methods. This rule is combined with the assumption of rigid‐ideal plastic behaviour of the shear connectors. Still, the real characteristics of most of today's usual shear connectors differ considerably from these assumptions, even more for shear connectors used in combination with metal decking. The paper describes the results of a literature research conducted in order to obtain reliable values for the deformation capacity and the slip range of headed stud shear connectors. Based on these results, advanced design methods can be used to realise composite beams with more realistic lower limits for the degree of partial shear connection and thus better economic performance.

Formation of post-buckling shear mechanisms in stiffened web panels of slender steel plate girders

A series of validated finite element models are used to investigate the formation of mechanisms in stiffened slender web panels of steel plate girders under pure shear. The prototype girder is based on the seminal tests by Basler and has a web slenderness of 267. Six model cases are analyzed with variations in web panel aspect ratio (1, 1.5, and 3), steel yield strength (Grades 36 and 50), initial imperfection magnitude, and flange thickness. When loaded in shear, the web panels exhibit a 3-stage response: (1) elastic behavior, (2) web mechanism formation, and (3) panel mechanism. In Stage 1, the web initially exhibits an elastic in-plane shear response with no distinct buckling bifurcation. During this stage, the web’s initial out-of-plane imperfections become engaged in second-order bending along its compression diagonal. Concurrently, tension develops in the opposite diagonal as a non-uniform membrane stress field, with highest intensities at locations where second-order bending is low. In Stage 2, a web mechanism is formed when connected bands of thru-thickness von Mises yielding develop across the tension diagonal. These bands emerge at locations where tension membrane stresses interact with locations of maximum second-order bending stress in the buckled shape. The shear load at the end of web mechanism formation is recommended as a target for plastic limit state design because it marks a significant decrease in shear stiffness. In Stage 3, von Mises yielding continues to saturate the web panel, and the bounding flanges and transverse stiffeners become increasingly engaged in load redistribution from the plastified web. Any hardening increase in shear resistance during the panel mechanism stage is modest in magnitude (up to ∼10% for some cases in this study) and is heavily dependent on the sizing of the flanges and stiffeners to carry redistributed forces.

Design of an Injection Molding Tool With Exchangable Inserts

The aim of this work was to design an injection molding tool with replaceable inserts. The tool design is made for a BOY 15S injection molding machine. Based on the interpretation and comparison of the simulation results of the filling process, we optimized the plastic part design, the runner system and the location of the gates and cavities in order to maximize productivity and efficiency while minimizing cost. In the process of the tool design, we also considered the potential problems regarding the manufacturing process of the tool.