Linear Solar Concentrator Structural Optimization Using Variable Beam Cross Sections

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Moucun Yang ◽  
Yuezhao Zhu ◽  
Wei Fu ◽  
Garth Pearce ◽  
Robert A. Taylor
Keyword(s):  
Structural Optimization ◽  
Cross Sections ◽  
Cost Savings ◽  
Variable Cross Section ◽  
Optimization Approach ◽  
Variable Cross ◽  
Cross Sectional ◽  
Optical Efficiency ◽  
Metal Grid ◽  
Box Structure

The design and construction of solar concentrators heavily affects their optical efficiency, heat utilization, and cost. Current trough concentrators use an equivalent uniform beam with a metal grid substructure. In this conventional design, there is surplus stiffness and strength, which unnecessarily increases the overall weight and cost of the structure. This paper describes a variable cross section structural optimization approach (with the EuroTrough design, including safety factors, taken as an example) to overcome this issue. The main improvement of this design comes from keeping the beams rigid and strong near the two ends (at the torque box structure) while allowing the middle of the structure to be relatively weak. Reducing the cross-sectional area of the middle beams not only reduces the amount of material needed for the structure but also reduces the deflection of the reflector. In addition, a new connection structure between two neighboring concentrator elements was designed to reinforce the structure. The simulated results show that the concentrator's structural weight (including the torque box, endplates, and cantilever arms) is reduced by 13.5% (i.e., about 133 kg per 12 m long element). This represents a meaningful capital and installation cost savings while at the same time improving the optical efficiency.

Solar Concentrator Structural Optimization: A Variable Beam Cross Section Design

2017 ◽  
Author(s):  
Moucun Yang ◽  
Yuezhao Zhu ◽  
Wei Fu ◽  
Garth Pearce ◽  
Robert A. Taylor
Keyword(s):  
Structural Optimization ◽  
Cross Section ◽  
Cost Savings ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Maximum Displacement ◽  
Cross Sectional ◽  
Optical Efficiency ◽  
Box Structure ◽  
Section Design

The design and construction of solar concentrators heavily affects their cost, heat utilization and optical efficiency. Current trough concentrators support the reflector with an equivalent uniform beam configured from a metal grid sub-structure. Under gravity and wind loads, the support-structure stress distribution varies as a function of position of the structure and the tracking angle. In the conventional design, there is ample surplus stiffness and strength designed into some beams of the structure, which increases the overall weight and cost of the structure. This paper describes an approach towards structural optimization of trough concentrators (with the Eurotrough design taken as an example, that means that the safety factors and structure is similar with Eurotrough design) using a variable cross section beam. The main improvement of this approach comes from keeping the beams rigid and strong near the two ends (at the torque box structure) while allowing the middle of the structure to be relatively weak. Reducing the cross-sectional area of the central beams not only reduces amount of material needed for the structure but also reduces the deflection of the reflector. The simulated results show that the concentrator’s structural weight (including the torque box, endplates and cantilever arms) and the maximum displacement of the reflector are reduced about 15.3% (about 151.2kg per 12-metre long element) and 15.5%, respectively. This represents a meaningful capital and installation cost savings while at the same time improving the optical efficiency.

Longitudinal oscillation of a rod with a variable cross section

2019 ◽  
Vol 14 (2) ◽  
pp. 138-141
Author(s):  
I.M. Utyashev
Keyword(s):  
Cross Section ◽  
Natural Frequencies ◽  
Liouville Problem ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Independent Functions ◽  
The Cross ◽  
The Right

Variable cross-section rods are used in many parts and mechanisms. For example, conical rods are widely used in percussion mechanisms. The strength of such parts directly depends on the natural frequencies of longitudinal vibrations. The paper presents a method that allows numerically finding the natural frequencies of longitudinal vibrations of an elastic rod with a variable cross section. This method is based on representing the cross-sectional area as an exponential function of a polynomial of degree n. Based on this idea, it was possible to formulate the Sturm-Liouville problem with boundary conditions of the third kind. The linearly independent functions of the general solution have the form of a power series in the variables x and λ, as a result of which the order of the characteristic equation depends on the choice of the number of terms in the series. The presented approach differs from the works of other authors both in the formulation and in the solution method. In the work, a rod with a rigidly fixed left end is considered, fixing on the right end can be either free, or elastic or rigid. The first three natural frequencies for various cross-sectional profiles are given. From the analysis of the numerical results it follows that in a rigidly fixed rod with thinning in the middle part, the first natural frequency is noticeably higher than that of a conical rod. It is shown that with an increase in the rigidity of fixation at the right end, the natural frequencies increase for all cross section profiles. The results of the study can be used to solve inverse problems of restoring the cross-sectional profile from a finite set of natural frequencies.

scholarly journals Failure Analysis of Intersections of Large-Scale Variable Cross-Section Roadways in Deep Soft Rock and Study of Integrated Control Technology of Bolting and Grouting

2021 ◽  
Author(s):  
Shengrong Xie ◽  
Yiyi Wu ◽  
Dongdong Chen ◽  
Ruipeng Liu ◽  
Xintao Han ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Large Scale ◽  
Integrated Control ◽  
Soft Rock ◽  
Variable Cross Section ◽  
Surrounding Rock ◽  
Variable Cross ◽  
Geological Environment ◽  
Cable Bolt

Abstract In deep underground mining, achieving stable support for roadways along with long service life is critical and the complex geological environment at such depths frequently presents a major challenge. Owing to the coupling action of multiple factors such as deep high stress, adjacent faults, cross-layer design, weak lithology, broken surrounding rock, variable cross-sections, wide sections up to 9.9 m, and clusters of nearby chambers, there was severe deformation and breakdown in the No. 10 intersection of the roadway of large-scale variable cross-section at the − 760 m level in the Nanfeng working area of the Wuyang Coal Mine. As there are insufficient examples in engineering methods pertaining to the geological environment described above, the numerical calculation model was oversimplified and support theory underdeveloped; therefore, it is imperative to develop an effective support system for the stability and sustenance of deep roadways. In this study, a quantitative analysis of the geological environment of the roadway through field observations, borehole peeking, and ground stress testing is carried out to establish the FLAC 3D variable cross-section crossing roadway model. This model is combined with the strain softening constitutive (surrounding rock) and Mohr-Coulomb constitutive (other deep rock formations) models to construct a compression arch mechanical model for deep soft rock, based on the quadratic parabolic Mohr criterion. An integrated control technology of bolting and grouting that is mainly composed of a high-strength hollow grouting cable bolt equipped with modified cement grouting materials and a high-elongation cable bolt is developed by analyzing the strengthening properties of the surrounding rock before and after bolting, based on the Heok-Brown criterion. As a result of on-site practice, the following conclusions are drawn: (1) The plastic zone of the roof of the cross roadway is approximately 6 m deep in this environment, the tectonic stress is nearly 30 MPa, and the surrounding rock is severely fractured. (2) The deformation of the roadway progressively increases from small to large cross-sections, almost doubling at the largest cross-section. The plastic zone is concentrated at the top plate and shoulder and decreases progressively from the two sides to the bottom corner. The range of stress concentration at the sides of the intersection roadway close to the passageway is wider and higher. (3) The 7 m-thick reinforced compression arch constructed under the strengthening support scheme has a bearing capacity enhanced by 1.8 to 2.3 times and increase in thickness of the bearing structure by 1.76 times as compared to the original scheme. (4) The increase in the mechanical parameters c and φ of the surrounding rock after anchoring causes a significant increase in σc and σt; the pulling force of the cable bolt beneath the new grouting material is more than twice that of ordinary cement grout, and according to the test, the supporting stress field shows that the 7.24 m surrounding rock is compacted and strengthened in addition to providing a strong foundation for the bolt (cable). On-site monitoring shows that the 60-day convergence is less than 30 mm, indicating that the stability control of the roadway is successful.

Experimental investigation on the thermal performance of Si micro-heat pipe with different cross-sections

2017 ◽  
Vol 31 (30) ◽  
pp. 1750279 ◽  
Author(s):  
Mohammad Hamidnia ◽  
Yi Luo ◽  
Xiaodong Wang ◽  
Congming Li
Keyword(s):  
Thermal Management ◽  
Thermal Performance ◽  
Cross Sections ◽  
Integrated Circuit ◽  
Thermal Characteristics ◽  
Cost Savings ◽  
Working Fluid ◽  
Cross Sectional ◽  
Si Substrates ◽  
Silicon Based

Increasing component densities of the integrated circuit (IC) and packaging levels has led to thermal management problems. Si substrates with embedded micro-heat pipes (MHPs) couple good thermal characteristics and cost savings associated with IC batch processing. The thermal performance of MHP is intimately related to the cross-sectional geometry. Different cross-sections are designed in order to enhance the backflow of working fluid. In this experimental study, three different Si MHPs with same hydraulic diameter and various cross-sections are fabricated by micro-fabrication methods and tested under different conditions of fluid charge ratios. The results show that the trapezoidal MHP associated with rectangular artery which is charged with 40% of vapor chamber’s volume has the best thermal performance. This silicon-based MHP is a passive approach for thermal management, which could widen applications in the commercial electronics industry and LED lightings.

scholarly journals Energy Absorption of Aluminium Extrusions Filled with Cellular Materials Under Axial Crushing: Study of the Interaction Effect

2020 ◽  
Vol 10 (23) ◽  
pp. 8510
Author(s):  
Javier Paz ◽  
Miguel Costas ◽  
Jordi Delgado ◽  
Luis Romera ◽  
Jacobo Díaz
Keyword(s):  
Energy Dissipation ◽  
Cross Sections ◽  
Interaction Effect ◽  
Unit Volume ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Polymeric Foam ◽  
Axial Crushing ◽  
Foam Filled ◽  
Thin Walled

This investigation focuses on the interaction effect during the quasi-static axial crushing of circular and square thin-walled aluminium extrusions filled with polymeric foam or cork. The increment in the absorbed energy due to interactions between materials was assessed using a validated numerical model calibrated with experimental material data. Simulations were run with variable cross-section dimensions, thickness, and foam density. The results were used to adjust the parameters of design formulas to predict the average crush forces of foam- and cork-filled thin-walled tubes. The analysis of the energy dissipation per unit volume revealed that the highest increments due to the interaction between materials appeared in the foam-filled square extrusions. Energy dissipation increased with higher density foams for both cross-sections due to a stronger constraint of the aluminium walls, and thus a reduction of the folding length. Thinner tube walls also delivered a higher improvement in the energy dissipation per unit volume than those with thicker walls. The contribution of friction was also quantified and investigated.

scholarly journals Characterization of Soft Tooling Photopolymers and Processes for Micromixing Devices with Variable Cross-Section

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 970
Author(s):  
J. Israel Martínez-López ◽  
Héctor Andrés Betancourt Cervantes ◽  
Luis Donaldo Cuevas Iturbe ◽  
Elisa Vázquez ◽  
Edisson A. Naula ◽  
...  
Keyword(s):  
Flow Regime ◽  
Cross Section ◽  
Cross Sections ◽  
Microfluidic Devices ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Multiple Cross ◽  
3D Printed

In this paper, we characterized an assortment of photopolymers and stereolithography processes to produce 3D-printed molds and polydimethylsiloxane (PDMS) castings of micromixing devices. Once materials and processes were screened, the validation of the soft tooling approach in microfluidic devices was carried out through a case study. An asymmetric split-and-recombine device with different cross-sections was manufactured and tested under different regime conditions (10 < Re < 70). Mixing performances between 3% and 96% were obtained depending on the flow regime and the pitch-to-depth ratio. The study shows that 3D-printed soft tooling can provide other benefits such as multiple cross-sections and other potential layouts on a single mold.

Analysis of Flexible Roll Forming Process with Arc Shape Panel

2015 ◽  
Vol 799-800 ◽  
pp. 439-442
Author(s):  
Ya Zhang ◽  
Dae Hwan Yoon ◽  
Dong Won Jung
Keyword(s):  
Cross Sections ◽  
High Strength ◽  
Variable Cross Section ◽  
Roll Forming ◽  
Variable Cross ◽  
Transportation Engineering ◽  
Forming Process ◽  
Flexible Roll Forming ◽  
Flexible Roll ◽  
Arc Shape

Roll forming is a highly useful and important forming technique for sheet metal. As an economic profile product, roll forming products are widely used in transportation, engineering machinery, and civil construction because of their uniform sections, high strength, and low energy consumption[1]. Roll forming is a rapid processing operation used for transforming flat sheets of material into useful profiled sections. However, a lot of components used in the automobile, railway cars, ship construction, and building industries have variable cross sections. Therefore, flexible roll forming was developed recently to produce variable cross section profiles.

scholarly journals Exact Longitudinal Vibration Characteristics of Rods with Variable Cross-Sections

2011 ◽  
Vol 18 (4) ◽  
pp. 555-562 ◽  
Author(s):  
Bulent Yardimoglu ◽  
Levent Aydin
Keyword(s):  
Differential Equation ◽  
Cross Section ◽  
Cross Sections ◽  
Longitudinal Vibration ◽  
Transformation Method ◽  
Variable Cross ◽  
Cross Sectional ◽  
Cross Section Area ◽  
Section Area ◽  
Sinusoidal Functions

Longitudinal natural vibration frequencies of rods (or bars) with variable cross-sections are obtained from the exact solutions of differential equation of motion based on transformation method. For the rods having cross-section variations as power of the sinusoidal functions ofax+b, the differential equation is reduced to associated Legendre equation by using the appropriate transformations. Frequency equations of rods with certain cross-section area variations are found from the general solution of this equation for different boundary conditions. The present solutions are benchmarked by the solutions available in the literature for the special case of present cross-sectional variations. Moreover, the effects of cross-sectional area variations of rods on natural characteristics are studied with numerical examples.

scholarly journals Structural Optimization and Experimental Research of High-rise Guyed Tower

2021 ◽  
Vol 245 ◽  
pp. 02006
Author(s):  
Wu Jing ◽  
Han Junke ◽  
Ye Fang ◽  
Qi Wenyan ◽  
Yu Jinshan ◽  
...  
Keyword(s):  
Structural Optimization ◽  
Cross Section ◽  
Engineering Application ◽  
Variable Cross Section ◽  
Variable Cross ◽  
High Rise ◽  
Advantages And Disadvantages ◽  
Test Study ◽  
Uniform Cross Section ◽  
Guyed Towers

In this paper, the structural optimization of high-rise guyed tower is carried out for the guyed wire and tower column schemes. The schemes are compared from the four guyed wires and eight guyed wires, the width of the tower column, the uniform cross-section tower column and the variable cross-section tower column, etc. And the single-column tower with eight guyed wires and variable cross-section is recommended for the high-rise guyed tower. Through the full-scale test study of the high-rise guyed tower, the safety of the high-rise guyed tower structural optimization and the feasibility of engineering application are verified. According to the technical and economic analysis of traditional self-supporting towers and high-rise guyed towers recommended in this paper, it can be seen that the weight and total cost of the high-rise guyed towers are 75.3% and 88.5% of the traditional self-supporting towers respectively, demonstrating the technical and economic advantages of the high-rise guyed towers. The advantages and disadvantages of high-rise guyed towers and self-supporting towers are summarized for reference in engineering design.

scholarly journals Theoretical and Experimental Research of The Stability of The Eccentrically Loaded Steel Columns with Variable Cross–Section

2018 ◽  
Vol 7 (3.2) ◽  
pp. 458
Author(s):  
Gennady Trusov ◽  
Vladimir Ruban
Keyword(s):  
Cross Section ◽  
Research Work ◽  
Variable Cross Section ◽  
Suggested Method ◽  
National Standards ◽  
Discrete Models ◽  
Practical Calculation ◽  
Variable Cross ◽  
Cross Sectional ◽  
Steel Columns

The article deals with the problem of determining the ultimate load for the eccentrically loaded steel columns with variable-cross section.The purpose of the research work is to offer an evaluation technique and practical calculation of load-bearing ability of the beam-columns with variable cross-section on the basis of numerical research, which will allow to consider the true form of element deflection curve, the effect of cross-section form, physical nonlinearity of the material, and variety of element boundary conditions. The distinctive characteristic of the suggested method is usage of the discrete models for cross-sectional parts, for the true stress-strain curves of the materials, and for the other input data. The method was tested and the results were compared to known theoretical solutions and national standards. To establish the reliability of the developed method, the experimental study of steel columns with variable cross-section was conducted. The suggested method allows to obtain column curves tables of lowering coefficients for these elements, that can be used in practice of civil engineering, and are convenient with national standards and Eurocode. 

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