Module-Based Static Structural Design of a Modular Reconfigurable Robot

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Richard Phillip Mohamed ◽  
Fengfeng (Jeff) Xi ◽  
Allan Daniel Finistauri
Keyword(s):  
Structural Design ◽  
Design Method ◽  
Optimal Solution ◽  
Local Deformation ◽  
Design Stage ◽  
Coordinate Frame ◽  
Reconfigurable Robots ◽  
Nonlinear Approach ◽  
Reconfigurable Robot

In this paper, the structural design of modular reconfigurable robots (MRRs) is studied. This problem is defined as the determination of proper module sizes according to the robot’s payload and end-effector deflection specifications. Because an MRR has multiple configurations, a simple design process is proposed in order to avoid performing the structural design stage at each configuration. The final structural design is only carried out at a single configuration that can guarantee the robot’s satisfactory performance for all remaining feasible configurations. It is shown that the module structural design stage can be performed at the local coordinate frame of each module. While the module local force requirement can be fully determined, the determination of the module local deformation requirement is redundant. Thus, there can exist multiple design solutions. To overcome this problem, a nonlinear approach using a genetic algorithm is used to search for an optimal solution. Finally, a design simulation is performed on an example MRR, and the results show the effectiveness of the proposed design method.

Simple Models for Periodic Lattices

1991 ◽  
Author(s):  
Serge Abrate
Keyword(s):  
Natural Frequencies ◽  
Periodic Structures ◽  
Optimal Solution ◽  
Mode Shapes ◽  
Design Stage ◽  
Continuum Models ◽  
Original Structure ◽  
Vibration Modes ◽  
Equivalent Properties

Abstract In many applications, the dynamic behavior of large periodic structures must be modeled accurately, thus requiring the determination of a significant number of natural frequencies and mode shapes. In order to perform that task most efficiently, a continuum modeling approach can be adopted. The discrete structure is then replaced by a continuum model which can be analyzed more efficiently. Therefore, at the design stage many analyses can be performed while searching for the optimal solution. Known structural models are usually used as continuum models, and several methods are available to determine the equivalent properties from the properties of the original structure. This task is usually cumbersome, and in addition, in certain cases, continuum models cannot represent all modes of deformation. In this article, a simple approach to develop continuum models without explicit reference to an existing structural theory is presented. Very accurate results are obtained, and all vibration modes can now be handled easily.

Numerical evaluation of hydrodynamic characteristics of planing hulls by using a hybrid method

2021 ◽  
pp. 147509022199024
Author(s):  
Emre Kahramanoglu ◽  
Silvia Pennino ◽  
Huseyin Yilmaz
Keyword(s):  
Experimental Data ◽  
Hybrid Method ◽  
Design Stage ◽  
Hydrodynamic Characteristics ◽  
Calm Water ◽  
Preliminary Design Stage ◽  
Reduction Function ◽  
Hull Forms ◽  
Good Agreement

The hydrodynamic characteristics of the planing hulls in particular at the planing regime are completely different from the conventional hull forms and the determination of these characteristics is more complicated. In the present study, calm water hydrodynamic characteristics of planing hulls are investigated using a hybrid method. The hybrid method combines the dynamic trim and sinkage from the Zarnick approach with the Savitsky method in order to calculate the total resistance of the planing hull. Since the obtained dynamic trim and sinkage values by using the original Zarnick approach are not in good agreement with experimental data, an improvement is applied to the hybrid method using a reduction function proposed by Garme. The numerical results obtained by the hybrid and improved hybrid method are compared with each other and available experimental data. The results indicate that the improved hybrid method gives better results compared to the hybrid method, especially for the dynamic trim and resistance. Although the results have some discrepancies with experimental data in terms of resistance, trim and sinkage, the improved hybrid method becomes appealing particularly for the preliminary design stage of the planing hulls.

Innovative Use of Profiled Steel Plates for Seismic Structural Performance

2005 ◽  
Vol 8 (3) ◽  
pp. 247-257 ◽  
Author(s):  
Y. Fukumoto ◽  
T. Takaku ◽  
T. Aoki ◽  
K. A. S. Susantha
Keyword(s):  
Numerical Analysis ◽  
Seismic Performance ◽  
Structural Design ◽  
Design Method ◽  
Steel Plates ◽  
Structural Performance ◽  
Cyclic Testing ◽  
Beam Columns ◽  
Bridge Bents ◽  
Hot Rolled

This paper presents the innovative use of hot-rolled thickness-tapered mill products, longitudinally profiled (LP) plates, for the seismic performance of bridge bents of single and portal framed piers. The study involves the inelastic cyclic testing and numerical analysis of tested beam-columns and portal frames in order to evaluate the effects of tapering ratios of LP plates, penetration of yielding, and number of locally buckled panels on their structural ductility. A structural design method is proposed for the portal frames having LP panels under cyclic loadings.

Research and Application of High-Efficiency Multi-Cyclone Dust Removal

2011 ◽  
Vol 109 ◽  
pp. 400-404
Author(s):  
Yan Hong Yang ◽  
Da Fu Ni
Keyword(s):  
Structural Design ◽  
High Efficiency ◽  
Dust Removal ◽  
Working Principle ◽  
Selection Of

Performance and working principle of high-efficiency multi-cyclone were analyzed, and the structural design shortage of original high-efficiency multi-cyclone was pointed out. Its structure was researched and designed, including determination of setting chamber and pipe number, selection of material and the design of cyclones.

A Synthesis of Aluminum Crewboat Structural Design

1982 ◽  
Vol 19 (01) ◽  
pp. 52-72
Author(s):  
William A. Henrickson ◽  
John S. Spencer
Keyword(s):  
Structural Design ◽  
Beam Theory ◽  
Coast Guard ◽  
Observation Data ◽  
Plate Girders ◽  
Worked Example ◽  
Theory Versus ◽  
Grillage Analysis ◽  
Design Stress

The need exists for a simplified structural review guide to enable U.S. Coast Guard marine inspectors to verify the structural adequacy of aluminum crewboats. The authors have developed such a guide. Typical existing crewboat forms and service speeds have been used to reduce the determination of impact pressures to a function of length and displacement. A design stress limit for the cyclic loading of the bottom structure has been determined based on wave observation data. Plating design has been verified by a comparison of sizing by beam theory versus elastoplastic analysis. A simplified grillage analysis has been used to determine the level of support provided by longitudinal plate girders or keelsons. A worked example and tables of section moduli for typical extrusions attached to plating are included as appendices.

A time-varying reliability-based robust design method considering overall efficiency of axial piston pump

2021 ◽  
pp. 1748006X2110661
Author(s):  
Zunling Du ◽  
Yimin Zhang
Keyword(s):  
Energy Conversion ◽  
Robust Design ◽  
Design Method ◽  
Design Stage ◽  
Structure Parameters ◽  
Time Varying ◽  
Design Variables ◽  
Reliability Method ◽  
Overall Efficiency ◽  
Axial Piston

Axial piston pumps (APPs) are the core energy conversion components in a hydraulic transmission system. Energy conversion efficiency is critically important for the performance and energy-saving of the pumps. In this paper, a time-varying reliability design method for the overall efficiency of APPs was established. The theoretical and practical instantaneous torque and flow rate of the whole APP were derived through comprehensive analysis of a single piston-slipper group. Moreover, as a case study, the developed model for the instantaneous overall efficiency was verified with a PPV103-10 pump from HYDAC. The time-variation of reliability for the pump was revealed by a fourth-order moment technique considering the randomness of working conditions and structure parameters, and the proposed reliability method was validated by Monte Carlo simulation. The effects of the mean values and variance sensitivity of random variables on the overall efficiency reliability were analyzed. Furthermore, the optimized time point and design variables were selected. The optimal structure parameters were obtained to meet the reliability requirement and the sensitivity of design variables was significantly reduced through the reliability-based robust design. The proposed method provides a theoretical basis for designers to improve the overall efficiency of APPs in the design stage.

Impact on Beams

1936 ◽  
Vol 3 (2) ◽  
pp. A55-A61
Author(s):  
H. L. Mason
Keyword(s):  
Historical Development ◽  
Contact Region ◽  
Local Deformation ◽  
Lateral Vibration ◽  
Transverse Impact ◽  
Concentrated Mass ◽  
Impact Theory ◽  
Inelastic Impact ◽  
Maximum Contact

Abstract This paper deals with transverse impact on beams the mass of which is of importance. Experimental results are presented for comparison with theory. Impacts which appear single to the eye are shown to consist in reality of several blows in quick succession. Section 1 of the paper traces the historical development of this subject by discussing the investigations of Young, Hodgkinson, Cox, Saint Venant, and Timoshenko. Section 2 treats a simplified system in which a concentrated mass strikes a smaller concentrated mass having a “soft” spring restraint. For elastic impact, theory predicts for the struck mass a path composed of sinusoidal elements separated by instantaneous blows. For inelastic impact it predicts a joint harmonic motion. Records of the paths of both masses were obtained experimentally. Section 3 of the paper uses Timoshenko’s method of combining local deformation of the contact region with lateral vibration of the beam. An experimental investigation of maximum contact pressure and of blow duration gives what is believed to be the first confirmation of this theory. Section 4 describes an experimental determination of flexural stresses in elastic and inelastic impact on a 3-in. I-beam by the use of a Westinghouse magnetic strain gage. The indication is that stresses may be higher than those calculated by the usual approximations.

Exploring the Design Space Using a Surrogate Model Approach With Digital Human Modeling Simulations

2018 ◽  
Author(s):  
Salman Ahmed ◽  
Mihir Sunil Gawand ◽  
Lukman Irshad ◽  
H. Onan Demirel
Keyword(s):  
Human Factors ◽  
Surrogate Model ◽  
Human Performance ◽  
Design Method ◽  
Human Subjects ◽  
Design Stage ◽  
Digital Human Modeling ◽  
Design Variables ◽  
Human Modeling ◽  
Digital Human

Computational human factors tools are often not fully-integrated during the early phases of product design. Often, conventional ergonomic practices require physical prototypes and human subjects which are costly in terms of finances and time. Ergonomics evaluations executed on physical prototypes has the limitations of increasing the overall rework as more iterations are required to incorporate design changes related to human factors that are found later in the design stage, which affects the overall cost of product development. This paper proposes a design methodology based on Digital Human Modeling (DHM) approach to inform designers about the ergonomics adequacies of products during early stages of design process. This proactive ergonomics approach has the potential to allow designers to identify significant design variables that affect the human performance before full-scale prototypes are built. The design method utilizes a surrogate model that represents human product interaction. Optimizing the surrogate model provides design concepts to optimize human performance. The efficacy of the proposed design method is demonstrated by a cockpit design study.

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