Constraint Diagram Research Articles

An Innovation of Flap Design for Energy Efficiency Lightweight Flying Vehicle Analysis

The design of the flying vehicles (FV) is becoming popular and it is very important nowadays. It is drafted in various circumstances and situations such as the military and transportation. The development of flying vehicles is different from ordinary airplanes because of its ability to fly in multiple directions. In this study, a new design for Malaysia was produced based on prototypes from previous models available in Japan. This design improved that it can has better stability of using fans and flaps on flying vehicles. This research paper is concerned with a flying vehicle that can fly a load of up to 480kg with a speed of up to 300km/h. This study is focusing on observed the existing flap design in the recognized literature for current flying vehicles. The plan accomplishes the energy efficiency of the flying vehicles. From the simulation of constraint diagram, the design of the aircraft was optimized; with the initial design of the wing, air foil designing with high performance of motor was done. Propeller and flap was design according to safety standard to fit in for the FV. The design of the new FV flap were compared to the existing model from the teTra aviation corp which was designed in Japan. The result of the new design FV flying vehicle will provide a clearer picture for the new concept that improvement flying time 35 % from the normal design.

Differential Quadrature Method for Partial Differential Dynamic Equations of Beam–Ring Structure

The partial differential equations of a circular truss beam–ring structure with antenna extended and locked are studied. The differential quadrature method is used to discretize the differential equations and boundary conditions in a spatial domain. The method of equation substitution and the method of boundary conditions are directly substituted into the internal discrete equations and are used to deal with the boundary conditions. The natural frequency of the beam–ring structure is calculated and verified by the natural frequency obtained by Galerkin’s method in paper (Wu et al., “Vibration Frequency Analysis of Beam–Ring Structure for Circular Deployable Truss Antenna,” International Journal of Structural Stability and Dynamics, Vol. 19, No. 2, 2019, Paper 1950012). To solve the problem when there are multiple mixed boundary conditions at a point, the method of replacing the internal discrete equation with boundary conditions is not unique and the solution accuracy is low, so the differential algebraic equations are used to replace the boundary conditions directly into the internal discrete equation, and the iterative scheme is established. Finally, the fourth-order-Runge–Kutta method is used to solve the problem. Based on the numerical results, the two methods are compared by using a 200s time history diagram, 10,000s displacement constraint diagram, 10,000s velocity constraint diagram, etc. The results show that the mixed boundary conditions can be solved more accurately by using differential algebraic equations, and the stability of constraints can be maintained under long-time simulation.

Design of an unmanned aircraft system for high-altitude 1\xa0kW fuel cell power system

A proton exchange membrane (PEM) fuel cell is particularly considered as a prime power supply for a fuel cell-powered unmanned aircraft system (UAS) as it possesses a very high-power density in comparison with other fuel cell types, hence a high potential to be used for high altitude long endurance (HALE) UAS flights. This paper will focus on examining the design requirements for the UAS-based 1 kW PEM fuel cell for high altitude operation (10–11 km), which can be correlated into a quantitative data to produce a design constraints diagram. The maximum take-off mass, endurance, and geometries for potential UAS design are estimated. Four different geometrical design profiles are developed and presented. The resulting geometries are analysed and the design parameters of the estimated 1 kW design yielded an aircraft of maximum take-off mass 34.8 kg, wingspan of 10.4 m, cruising speed 20 m/s, stall speed 11.23 m/s, and maximum endurance of 4 h. The constraint diagram deploys these assumptions as well as values generated through the design calculations to form a possible design of which the 1 kW UAS falls slightly outside of the possible design space; this is due to the minimum thrust-to-weight ratio required to achieve the desired service ceiling; however, further alterations and adjustments on the design and mission requirements are provided to place the design of the UAS within the possible design space.

Initial Sizing Methodology for Hybrid-Electric General Aviation Aircraft

Electric and hybrid-electric propulsion offer unique possibilities to improve aircraft efficiency and performance. The potential advantages are fuel savings, lower emissions, and reduced noise. Because hybrid-electric aircraft generally apply multiple power sources, they can be designed to sustain flight if certain parts of the propulsion system fail. However, their additional degrees of freedom increase the complexity of the design process. This paper describes a methodology of an initial sizing algorithm that considers aircraft with hybrid-electric propulsion systems. A central element is a modified constraint diagram, which matches the power-to-weight ratio, wing loading, and the hybridization of power . It is coupled with a mission performance analysis that is capable of dealing with multiple energy sources and defines the mass and size of all relevant aircraft components. The modified constraint diagram also allows a visual assessment of the sizing results, and thereby greater insight into the design space.

Conceptual design of high performance Unmanned Aerial Vehicle

In current day’s Unmanned Aerial Vehicle (UAV) are widely used in every field, almost from military till the commercial purpose. Usage of UAV has decreased the burden on the human, where the manpower and risks during critical conditions (war fields) are reduced. Therefore the demand for the development of the unmanned aerial Vehicle is high. Interpreting the conceptual design data of UAV is difficult because of lack of availability of their data sheets. This paper is addressed to develop a conceptual design process of high-performance UAV, which carries a maximum payload of about 300kg and can travel for the maximum range 900km/hrs. For about 50 hours of maximum endurance. Where these three parameters are considered as the main requirements. By drawing constraint diagram, feasible design space for the aircraft was frozen; using which initial sizing of the wing, wing airfoil selection, and a suitable power-plant selection was done. Fuselage design was carried out looking at the available literature on the existing aircrafts. Propeller design was done to match the thrust requirements obtained from the constraint diagram. Empennage design was done to achieve the desired static margin of the aircraft. This process completes the conceptual design of UAV, where designed aircraft meets the requirement. The outcome of this paper enhances the understanding of the conceptual design process for the academicians as well as the researchers.

Residual harmfulness of a defect after repairing by a composite patch

The harmfulness of a defect in a CT specimen made in an API 5L X52 steel pipe is evaluated after being repaired with a composite patch. Due to the fact that the presence of a composite patch improves the fracture resistance but also modifies the constraint, a two-parameter fracture approach is used. More precisely, the stress field at the tip of a notch-like defect repaired by a boron/epoxy bonded composite patch is evaluated by the notch stress intensity factor Kρ and the effective T-stress Tef as constraint parameter. An assessment point of coordinates [Tef−Kρ] is reported in the Fracture Toughness–Constraint Diagram␣(FTCD). A line from origin O and passing through this assessment point intercepts the Failure Material Master Curve. This procedure allows us to determine a patch repairing index which is a measure of the residual harmfulness of a crack-like defect after repair. The repair with a composite patch reduces significantly the defect’s severity and increases the service life.

A FRAMEWORK FOR INTERPRETING FAST RADIO TRANSIENTS SEARCH EXPERIMENTS: APPLICATION TO THE V-FASTR EXPERIMENT

We define a framework for determining constraints on the detection rate of fast transient events from a population of underlying sources, with a view to incorporating beam shape, frequency effects, scattering effects, and detection efficiency into the metric. We then demonstrate a method for combining independent datasets into a single event rate constraint diagram, using a probabilistic approach to the limits on parameter space. We apply this new framework to present the latest results from the V-FASTR experiment, a commensal fast transients search using the Very Long Baseline Array (VLBA). In the 20 cm band, V-FASTR now has the ability to probe the regions of parameter space of importance for the observed Lorimer and Keane fast radio transient candidates, by combining the information from observations with differing bandwidths, and properly accounting for the source dispersion measure, VLBA antenna beam shape, experiment time sampling, and stochastic nature of events. We then apply the framework to combine the results of the V-FASTR and ATA Fly's Eye experiments, demonstrating their complementarity. Expectations for fast transients experiments for the SKA Phase I dish array are then computed, and the impact of large differential bandwidths is discussed.

Generalized constraint diagrams and the classical decision problem

Constraint diagrams were proposed as a means of modelling software systems, with generalized constraint diagrams being a recent refinement. It is known that generalized constraint diagrams are more expressive than constraint diagrams and can express any first-order logic statement that uses monadic or dyadic predicates. Thus, the generalized constraint diagram logic is undecidable. In this article, we develop a decision procedure for the so-called existential fragment of generalized constraint diagrams, building on previous work for a simpler, less expressive, fragment of the logic.

Mission Performance Considered as Point Performance in Aircraft Design

DOI: 10.2514/1.C031290 The cruise or loiter performance of an aircraft is intimately tied to its wing loading and its thrust-to-weight ratio. Paradoxically, mission performance is often not considered when these fundamental aircraft parameters are determined in conceptual design. In this paper, the traditional constraint diagram is extended to include contours of range or endurance parameter. These performance metrics represent the mission-performance capability of the aircraft without sizing the aircraft to a particular mission. This gives the designer an immediate and intuitive understanding of the tradeoff between the point and mission performance of the aircraft. The potential freedom for the designer to choose the operating condition of the aircraft is also considered. This improved constraint diagram presents the designer with a more complete basis for understanding and weighing the consequences of decisions.

Evaluating and generalizing constraint diagrams

The constraint diagram language was designed to be used in conjunction with the unified modelling language (UML), primarily for placing formal constraints on software models. In particular, constraint diagrams play a similar role to the textual object constraint language (OCL) in that they can be used for specifying system invariants and operation contracts in the context of a UML model. Unlike the OCL, however, constraint diagrams can be used independently of the UML. In this paper, we illustrate a range of intuitive and counter-intuitive features of constraint diagrams and highlight some (potential) expressiveness limitations. The counter-intuitive features are related to how the individual pieces of syntax interact. A generalized version of the constraint diagram language that overcomes the illustrated counter-intuitive features and limitations is proposed. In order to discourage specification readers and writers from overlooking certain semantic information, the generalized notation allows this information to be expressed more explicitly than in the non-generalized case. The design of the generalized notation takes into account five language design principles which are discussed in the paper. We provide a formalization of the syntax and semantics for generalized constraint diagrams. Moreover, we establish a lower bound on the expressiveness of the generalized notation and show that they are at least as expressive as constraint diagrams.

A Decidable Constraint Diagram Reasoning System

Constraint diagrams are a visual notation designed for use by software engineers to formally specify information systems. In this paper we formalize a fragment of the constraint diagram language. A set of reasoning rules are defined and we prove that this set is both sound and complete. Given constraint diagrams D1 and D2 such that D2 is a semantic consequence of D1, to prove completeness we construct a proof of D2 from D1. A decision procedure can be extracted from this proof construction process and it follows that the system is decidable.

The semantics of augmented constraint diagrams

Constraint diagrams are a diagrammatic notation which may be used to express logical constraints. They generalize Venn diagrams and Euler circles, and include syntax for quantification and navigation of relations. The notation was designed to complement the Unified Modelling Language in the development of software systems. Since symbols representing quantification in a diagrammatic language can be naturally ordered in multiple ways, some constraint diagrams have more than one intuitive meaning in first-order predicate logic. Any equally expressive notation which is based on Euler diagrams and conveys logical statements using explicit quantification will have to address this problem. We explicitly augment constraint diagrams with reading trees, which provides a partial ordering for the quantifiers (determining their scope as well as their relative ordering). Alternative approaches using spatial arrangements of components, or alphabetical ordering of symbols, for example, can be seen as implicit representations of a reading tree. Whether the reading tree accompanies the diagram explicitly (optimizing expressiveness) or implicitly (simplifying diagram syntax), we show how to construct unambiguous semantics for the augmented constraint diagram.

Design analysis methodology for solar-powered aircraft

A methodology for conceptual design of solar-powered aircraft is described. The method is based on traditional design methodologies adapted to address the peculiar characteristics of solar-powered aircraft. The solar propulsion notation is applied to the analysis to create constraint diagrams that have takeoff wing loading ft = Wto/S as their independent variable, and the ratio of solar collector area to reference planform area R — Sce,,/S as their dependent variable. Constraints determined by the propulsion requirements for the design mission of the aircraft define a solution space on the constraint diagram. A design point is selected from within the solution space. Parametric estimates for component weights are then represented as wing loading portions. When these component wing loading portions are summed along with an expression for the required payload wing loading portion, they are equated to the design point wing loading. The resulting equation is solved for the required reference planform area, thus sizing the conceptual design. Three typical conceptual designs are described and analyzed, demonstrating the utility of the methodology.