Existing Design Methods Research Articles

Consolidation of Methods for Visualization and Management of Engineering Design Data Sets

Existing design support tools and methods struggle to deal with numerous data management situations that arise in medium and large-scale design projects. Authors analyse and compare the suitability and efficiency of several methods for managing and visualization of relationships between engineering objects and propose guidelines for building a framework/interface for consolidated usage of those methods in industrial practice. The proposed matrix- based consolidation methodology builds on findings gathered from two monitored design projects as well as previous research in areas of traceability and visualization. For engineering objects (data sets) that belong to one or two domains which are not hierarchically structured it is argued that a simple matrix interface is sufficient to record the relations. Furthermore, if the engineering objects are hierarchically structured the browser interface is suggested. In the most complex situation, where objects belong to multiple different domains the use of diagrams and digital whiteboards is suggested.

Controller design for integrating processes with inverse response and dead time based on standard forms

In chemical engineering, processes exhibiting an initial response to a step input change in the opposite direction of the final steady state can frequently be encountered. Processes exhibiting such characteristics are called inverse response processes and warrant a closer look. In addition, inverse response processes can include an integrator in their transfer function model. In the literature, there are only a few studies addressing control of integrating processes with inverse response. Existing design methods, usually, suggest the use of well-known proportional–integral–derivative (PID) controllers for the control of inverse response processes with an integrator. However, it has been proven by studies in the literature that PID controllers results in unsatisfactory closed-loop performances for integrating processes. Addition of inverse response makes the control of an integrating process more difficult to control. On the other hand, it has been shown that PI–PD controllers perform in very satisfactory closed-loop responses for a class of processes, including integrating processes as well. This paper gives the use of PI–PD controllers to improve the closed-loop performance of integrating processes with inverse response. Simulation examples are provided to illustrate the superiority of the proposed method over the existing ones.

Contribution of suction on the stability of reinforced-soil retaining wall

Existing design methods of a reinforced-soil retaining wall were established for walls with cohesionless soil backfill. However, local soil has been used widely in the construction of such a wall for economic reasons. Laboratory and numerical studies have pointed out the merit of using cohesive backfill in association with geosynthetic reinforcement. Since the compacted soil was in an unsaturated condition during the construction of the reinforced wall, the apparent cohesion derived from both soil mineralogy and suction could contribute to the stability of the wall. This paper considers methods to include the suction contribution to the existing design guidelines based on slope stability analysis, i.e. simplified method and simplified stiffness method. The analyses were carried out on a case study of geosynthetics reinforced soil retaining wall. Results show that the contribution of suction as part of cohesion existing in the cohesive backfill could be considered for the stability analysis of reinforced soil retaining walls using the available design guidelines.

Research on Interactive Routing of Cable in Virtual Environment

On the basis of analyzing the defects of existing design methods of cable wiring, the feasibility of interactive cabling design in virtual environment is pointed out. Based on the discrete control point, the geometric shape modeling method and the topological structure matrix modeling method based on the wire unit are presented. Adopt the method of real-time interactive cable modeling and wiring, explains the wiring process and control point positioning technology, and through the stratified multistage collision interference detection technology improve the authenticity of the wiring process and results. After the wiring design is completed, the statistical summary of the model information is compiled to generate various inventory reports to guide the actual production.

Multiphysics topology optimization for piezoelectric acoustic focuser

The application of piezoelectric materials allows many advantages such as reducing the number of parts and manufacturing cost of a mechanical system. Despite these merits, the performance predictions and optimization of piezoelectric-material-based devices are challenging because of the mutual coupling between electricity and mechanics. The analysis and the optimization become more challenging when acoustics are to be coupled with piezoelectric-material-based devices. In the present study, the mutual couplings among electric, mechanics, and acoustics are simulated and its applications for the topology optimization of an acoustic energy focuser are presented. Owing to the local optima issue, some blurred and unsuccessful layouts are obtained. To overcome this issue and impose the manufacturing constraint, a modified morphology density filter is also developed. With the presented approach, it is possible to determine some optimized piezoelectric rings to focus acoustic energy. Compared with the existing design methods, some better designs in terms of objective value can be obtained by the present approach.

Interactive design for additive manufacturing: a creative case of synchronous belt drive

As a digital and direct manufacturing technology, additive manufacturing (AM) presents a powerful and unrestrained revolution for creative design. However the breakthrough in manufacturing technology is yet to be followed by a breakthrough in design. Firstly, the state-of-the-art overview of the existing design methods for AM is presented. Furthermore, as part of a fully 3D printed robot we envisioned, this work mainly put forward a novel synchronous belt drive as an illuminating case with the potential and constraints of AM. After capturing the flexibility based on shape innovation, a new type of continuous trapezoidal tooth belt transmission without matrix was designed. Next, using the nonlinear finite elements method, the effect laws of belt’s parameters such as tooth height, tooth width, wedge angle and belt thickness were studied on the carrying capacity of belt transmission with pre-tensioning. Moreover, a new type of synchronous belt and timing pulleys were made via the 3D printing process of fused deposition modeling with the flexible polylactic acid (PLA) material. Lastly, a driving test was carried out and the experimental results showed that the presented 3D printed trapezoidal tooth belt transmission was stable, and could meet the requirements of low speed, small power transmission, especially apt to digital design and customization. This work completely demonstrates the intrinsic nature of digital design, interactive design and custom design from/with/for AM, as well as the ever-expanding room for innovation.

Prestressing bridge girders with carbon fiber–reinforced polymer: State of knowledge and research needs

Prestressing concrete bridge beams with composite materials has been investigated extensively within the last two decades. The outcomes of these research efforts, however, emerged only in a limited number of representative applications in the United States. This is partly due to a lack of comprehensive design guidelines for use by bridge engineers, especially in the American Association of State Highway and Transportation Officials Load and Resistance Factor Design format. An extensive review of literature related to the prestressing of concrete bridge beams with carbon fiber–reinforced polymer strands was conducted. A database of the beams prestressed with carbon fiber–reinforced polymer was established, and the existing design methods along with the required parameters were reviewed. Based on the collected data, the flexural and shear capacity of beams was calculated and compared with the experimentally obtained capacity and that obtained from selected design guidelines. Variables related to the design of carbon fiber–reinforced polymer prestressing that need calibration with dedicated material properties were examined, and the effects of carbon fiber–reinforced polymer on long- and short-term losses were identified.

Exploiting latent functional capabilities for resilience in design of engineering systems

In this paper, we address latent functional capabilities, capabilities that were neither intended nor recognized in the design process. We propose that latent capabilities can improve the resilience of engineering systems, enabling recovery of performance after disruptive events. Engineering systems are designed to meet their functional requirements, and have a limited ability to avoid critical failures. Normally, redundancies are put in place to reduce the impact of potential disruptions, adding to cost and complexity. An alternative is to uncover latent capabilities that can be used to recover from disruption by altering the function-form mapping. Existing design methods focus on intended, manifest functionality, and do not consider latent capabilities. With basis in design theory, we show that latent capabilities can enhance resilience, and demonstrate this using two illustrative cases. Further, we propose approaches to uncover latent capabilities in systems design, and discuss implications of using latent capabilities to enhance resilience.

Position-based tensegrity design

We propose a novel framework for the computational design of tensegrity structures, which are constructions made of struts and cables, held rigid by continuous tension between the elements. Tensegrities are known to be difficult to design---existing design methods are often restricted to using symmetric or templated configurations, limiting the design space to simple constructions. We introduce an algorithm to automatically create free-form stable tensegrity designs that satisfy both fabrication and geometric constraints, and faithfully approximate input geometric shapes. Our approach sidesteps the usual force-based approach in favor of a geometric optimization on the positions of the elements. Equipped with this formulation, we provide a design framework to explore the highly constrained space of tensegrity structures. We validate our method with simulations and real-world constructions.

Fatigue Life Assessment Method for Prestressed Concrete Sleepers

Concrete sleepers are one of the most important applications of a railway track system. Researchers have previously studied the impact load characteristics and ultimate load carrying capacity of a prestressed sleeper but research on the fatigue life of prestressed concrete sleepers is limited. Prestressed concrete sleeper fatigue damage is mainly due to the accumulation of defects, caused by the repeated load of wheel-rail interaction. Fatigue load, fatigue characteristics and the existing design methods of prestressed concrete sleeper are summarized in this paper. The commonly used fatigue assessment methods of concrete structures are also evaluated. Based on the results of former research result, this article presents a convenient fatigue life assessment method for a prestressed concrete sleeper, and contrasts with the test results. The insight information gained can be used to evaluate the service performance and predict the fatigue life of the concrete sleeper, as well providing design flexibility and broadening the design principle. The outcome of this study may also improve the rail track maintenance and inspection criteria, in order to establish an appropriate track condition monitoring network in practice.

Development of a new methodology to effectively predict the fracture properties of RAP mixtures

The existing design method for reclaimed asphalt pavement (RAP) mixtures assumes virgin and RAP binders fully blend. However, full blending may not occur and the impact of partial blending on mixture cracking performance is still unclear. A previous study revealed that RAP gradation, which is not currently considered from the standpoint of binder blending, controls the distribution of RAP binder within a mixture and consequently affects cracking performance. The objective of this study was to develop a methodology that overcomes the uncertainty of blending and effectively predicts fracture properties of RAP mixtures. This methodology is based on the evaluation of the interstitial component (IC) of a mixture (i.e. the fine portion that governs cracking performance) by means of a direct tension test named interstitial component direct tension (ICDT) test. Two RAP sources and four RAP contents were considered. ICDT specimens were produced by blending the fine portion of RAP and virgin aggregate with virgin binder in the same way and corresponding proportions as in RAP mixtures. Binder and mixture fracture properties from the previous study were used for comparison. Mixture and IC exhibited almost similar reduction in fracture energy density with increasing RAP content, whereas fully blended binder exhibited a less pronounced reduction. This indicated that IC better simulated the actual blending that occurred in mixtures. Mixtures with coarsely graded RAP (less RAP content in the IC) exhibited better fracture properties; thus, the key to satisfactory cracking performance appeared to be minimising the amount of RAP in IC. Consequently, the stiffening effect of RAP on the fine portion that controls cracking performance should be directly evaluated, instead of placing focus on the fully blended binder or the whole mixture. The ICDT test was proven to be a valuable tool to predict fracture properties of RAP mixtures.

Increase of energy efficiency in the low-pressure heater of PN-1100-25-6-1 type

Heat exchangers of various types (gas-gas, gas-liquid, liquid-liquid) are widely used in power plants of thermal power plants and nuclear power plants. Like any technical system, the heat exchange apparatus is estimated by the main quality indicator-energy efficiency. At present, most of the studies devoted to this issue are related to the determination of the intensification of the heat transfer process and the determination of the energy efficiency of convective heating surfaces. At the same time, both at the design stage, and especially for the functioning heat exchanger, it is required to determine its energy efficiency (further energy efficiency), which usually decreases with time. It is necessary to distinguish between the energy efficiency of the heat exchanger as a whole, in which the heat transfer occurs in the case of two-sided flow around the heat exchange surface and the energy efficiency of the surface on each side. (In the case of a heat exchanger with one-sided flow around the heat transfer surface, these concepts are often assumed to be identical, which is far from always correct). At the same time, after increasing the energy efficiency of the heat exchanger, due to the justified introduction of design changes, it is necessary to carry out a technical and economic calculation showing the means and time spent on the modernization of the apparatus. In the present paper, the existing design methods for increasing energy efficiency in low-pressure heaters of the PN-1100-25-6-1 type are considered and one of the promising ones is selected. The technical and economic calculation of this heater has been completed

A Novel SWMM Based Algorithm Application to Storm Sewer Network Design

An automated algorithm based on the dynamic hydrological and hydraulic simulation modules in Storm Water Management Model (SWMM) was developed to aid the design of storm sewer networks, provided that a layout is given. Numerical performance of the proposed algorithm was compared with the existing design methods with two application cases. The automated computation process of the sewer network design was divided into two stages and solved iteratively, determining pipe diameter and pipe slope, respectively. In the first stage, starting with a set of initial values including pipe diameter, pipe cover depth, and ground elevation at manholes, the iteration was carried out from the downstream to the upstream while the pipe slopes of the network were assumed to be fixed and the diameter of each pipe segment was calculated. In the second stage, pipe diameters calculated from the first stage were fixed and the pipe slopes were calculated successively from the downstream pipe segment to the upstream pipe segment. Every time the diameter or slope of a pipe segment was adjusted, the pipe flow rate, velocity, and flow depth were obtained by running SWMM hydrological and hydraulic simulation modules. The iteration terminated once the combination scheme of pipe diameters and slopes met the design ordinance which requires the pipe flows full under gravity in a design return period. A real urban sewer system in a hilly city and a benchmark sewer network from the literature were tested to validate the proposed automated algorithm, and good performance was shown. The automated design results explicitly show that the proposed storm sewer design approach leads to a quality solution with reduced computational effort.

FE modelling of the flexural behaviour of square and rectangular steel tubes filled with normal and high strength concrete

In this research, numerical investigations were carried out to study the behaviour of concrete filled steel tubes having square or rectangular cross-sections. Separate models were used for both normal strength concrete and high strength concrete. More than 50 experimental results were used to verify the FE model and it was found that the FE model accurately predicts the load-deflection curve and ultimate moment capacity of the Concrete filled steel tube (CFST) beams. Thereafter, a parametric study was carried out to evaluate the effect of depth-to-thickness ratio (20−200), compressive strength of infilled concrete (2–100MPa), shear span-to-depth ratio (1–8), depth-to-width ratio (0.6–2), and yield strength of steel tube (380–490MPa) on the flexural behaviour of square and rectangular CFST members. It was found that the depth-to-thickness ratio, yield strength of steel and height-to-width ratio has significant effect on the ultimate capacity of CFST beams. The effect of shear span-to-depth ratio and strength of infilled concrete was found to be marginal. Finally, the results of parametric study and experimental data available in literature were used to check the accuracy of the existing design methods presented in EC4 (2004), CIDECT, AISC (2010) and GB50936 (2014). From comparison, it was found that GB50936 (2014) was more accurate but unsafe for low strength infilled concrete. For all cases, EC 4 (2004) was found to be safe and hence is recommended.

Experimental and numerical study on member classification of I-section plate girders

Section classification is adopted by modern design codes and standards as a basic step in design process. Web-flange interaction is a significant feature that influence cross-sectional behavior but generally not included herein. Moreover, the overall member stability is also not considered during the classification procedure, which is an influential parameter in ultimate strength capacity. Besides the lack of considerations on interaction effects, the web resistance to shear buckling has to be investigated as well, especially for fabricated I-section plate girders. Tests of four specimens with high shear ratio are presented and investigated. It is observed that the features of local buckling of the constituent cross-sectional plate elements and the global lateral-torsional mode are closely inter-related. Insufficiencies in existing design methods are highlighted accordingly. The experimentally verified numerical modeling is carried out to conduct the parametric study. A member classification proposal based on normalized strength capacity is handed in for future Chinese steel design codes in a simple and plain form. Interactions between web-flange plate elements and local-global buckling modes are taken into account.

Rainfall and streamflow sensor network design: a review of applications, classification, and a proposed framework

Abstract. Sensors and sensor networks play an important role in decision-making related to water quality, operational streamflow forecasting, flood early warning systems, and other areas. In this paper we review a number of existing applications and analyse a variety of evaluation and design procedures for sensor networks with respect to various criteria. Most of the existing approaches focus on maximising the observability and information content of a variable of interest. From the context of hydrological modelling only a few studies use the performance of the hydrological simulation in terms of output discharge as a design criterion. In addition to the review, we propose a framework for classifying the existing design methods, and a generalised procedure for an optimal network design in the context of rainfall–runoff hydrological modelling.

PECULIARITIES OF DESIGN AND OPERATION OF WATER SUPPLY SYSTEMS OF HIGH-RISE BUILDINGS

In this article the problem of design and operation of water supply systems for high-rise buildings in Russia, including in Togliatt i, is considered. The system of water supply of highrise buildings in modern design conditions is substantiated. It is noted that the existing design methods are based on the norms of the last century, without taking into account modern developments in the fi eld of sanitary equipment and the requirements for resource saving. It is substantiated that in order to above-mentioned problems solution it is necessary to study the development trends of the regulatory base in the fi eld of high-rise construction; to determine the operational features of high-rise building water supply systems; to reveal factors aff ecting resource conservation in the water supply system of high-rise buildings; to study effi ciency of pumping units operation and peculiarities of their regulation; to evaluate the water-saving eff ect from the use of modern water-fi ttings.

Seismic behaviour of non-rectangular structural RC wall in the weak axis

Structural reinforced concrete (RC) walls can have very different lengths and widths. Previous investigations have focused on the seismic properties of structural RC walls in the strong axis in which the length of the wall is greater than the width of the wall. The seismic behaviour of structural RC walls in the weak axis, where the wall length is less than its width, is insufficiently investigated. This paper reports on experimental studies on the seismic behaviour of two non-rectangular RC walls loaded in the weak axis. The experimental results are presented in terms of cracking patterns, failure mechanisms, hysteresis responses, the component of deformation and the distributions of vertical strains in the flange. The experimental results are discussed, and emphasise the accuracy of existing design methods for non-rectangular RC walls in the weak axis, including design methods for the stiffness, the shear lag effect and the shear strength.

Genetic algorithm-based design method for multilevel anisotropic diffraction gratings

We developed a method for the design of multilevel anisotropic diffraction gratings based on a genetic algorithm. The method is used to design the multilevel anisotropic diffraction gratings based on input data that represent the output from the required grating. The validity of the proposed method was evaluated by designing a multilevel anisotropic diffraction grating using the outputs from an orthogonal circular polarization grating. The design results corresponded to the orthogonal circular polarization grating structures that were used to provide outputs to act as the input data for the process. Comparison with existing design methods shows that the proposed method can reduce the number of human processes that are required to design multilevel anisotropic diffraction gratings. Additionally, the method will be able to design complex structures without any requirement for subsequent examination by a human designer. The method can contribute to the development of optical elements by designing multilevel anisotropic diffraction gratings.

Prediction of Punching Shear Capacity of Two-Ways FRP Reinforced Concrete Slabs

An innovative solution to the corrosion problem is the use of fiber-reinforced polymer (FRP) as an alternative reinforcing material in concrete structures. In addition to the non corrodible nature of FRP materials, they also have a high strength-to-weight ratio that makes them attractive as reinforcement for concrete structures. Extensive research programs have been carried out to investigate the flexural behavior of concrete members reinforced with FRP reinforcement. On the other hand, the shear behavior of concrete members, especially punching shear of two-way slabs, reinforced with FRP bars has not yet been fully explored. The existing provisions for punching of slabs in most international design standards for reinforced concrete are based on tests of steel reinforced slabs. The elastic stiffness and bonding characteristics of FRP reinforcement are sufficiently different from those of steel to affect punching strength. In the present study, the equations of existing design standards for shear capacity of FRP reinforced concrete beams have been evaluated using the large database collected. The experimental punching shear strengths were compared with the available theoretical predictions, including the CSA S806 (CSA 2012), ACI-440.1R-15 (ACI 2015), BS 8110 (BSI 1997), JSCE (1997) a number of models proposed by some researchers in the literature. The existing design methods for FRP reinforced concrete slabs give conservative predictions for the specimens in the database. This paper also presents a simple yet improved model to calculate the punching shear capacity of FRPreinforced concrete slabs. The proposed model provides the accurate results in calculating the punching shear strengths of FRP-reinforced concrete slender slabs.