Static Design and Dynamic Analysis of Light Weight Machinery Support Structures

Author(s):  
Paul J. Remington ◽  
Henno Allik ◽  
Nathan Martin

Abstract Light weight truss-like structures to support shipboard machinery are currently under consideration for a variety of marine applications by the US Navy. The objective of this study was to develop the structural acoustic design principles for minimizing the transmission of vibration through the truss to the hull of a vessel and thereby reduce radiated sound. A design procedure was developed to select truss member sizes to satisfy specified design criteria, e.g., minimum weight, minimum radius of gyration, etc., while ensuring that the structure will support the design loads. The procedure interacts with the ANSYS finite element computer code to perform structural analysis. The resulting truss configurations were then analyzed to determine their dynamic performance using the SARA family of finite element programs that incorporate a continuum beam element to increase computational efficiency. A number of two dimensional and three dimensional truss configurations have been analyzed. Results will be presented illustrating the influence of a variety of design parameters on the force transmissibility between excitation point and truss support points. In addition the strong influence of local drive point admittance on the force transmissibility will be illustrated.

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 295
Author(s):  
Pao-Hsiung Wang ◽  
Yu-Wei Huang ◽  
Kuo-Ning Chiang

The development of fan-out packaging technology for fine-pitch and high-pin-count applications is a hot topic in semiconductor research. To reduce the package footprint and improve system performance, many applications have adopted packaging-on-packaging (PoP) architecture. Given its inherent characteristics, glass is a good material for high-speed transmission applications. Therefore, this study proposes a fan-out wafer-level packaging (FO-WLP) with glass substrate-type PoP. The reliability life of the proposed FO-WLP was evaluated under thermal cycling conditions through finite element simulations and empirical calculations. Considering the simulation processing time and consistency with the experimentally obtained mean time to failure (MTTF) of the packaging, both two- and three-dimensional finite element models were developed with appropriate mechanical theories, and were verified to have similar MTTFs. Next, the FO-WLP structure was optimized by simulating various design parameters. The coefficient of thermal expansion of the glass substrate exerted the strongest effect on the reliability life under thermal cycling loading. In addition, the upper and lower pad thicknesses and the buffer layer thickness significantly affected the reliability life of both the FO-WLP and the FO-WLP-type PoP.


2011 ◽  
Vol 121-126 ◽  
pp. 1744-1748
Author(s):  
Xiang Yang Jin ◽  
Tie Feng Zhang ◽  
Li Li Zhao ◽  
He Teng Wang ◽  
Xiang Yi Guan

To determine the efficiency, load-bearing capacity and fatigue life of beveloid gears with intersecting axes, we design a mechanical gear test bed with closed power flow. To test the quality of its structure and predict its overall performance, we establish a three-dimensional solid model for various components based on the design parameters and adopt the technology of virtual prototyping simulation to conduct kinematics simulation on it. Then observe and verify the interactive kinematic situation of each component. Moreover, the finite element method is also utilized to carry out structural mechanics and dynamics analysis on some key components. The results indicate that the test bed can achieve the desired functionality, and the static and dynamic performance of some key components can also satisfy us.


2007 ◽  
Vol 353-358 ◽  
pp. 2855-2859
Author(s):  
W.C. Lee ◽  
Chae Sil Kim ◽  
J.B. Na ◽  
D.H. Lee ◽  
S.Y. Cho ◽  
...  

Since most marine engines are generally very huge and heavy, it is required to keep safety from accidents in dealing them. Several types of lifting lugs have been used to assemble hundred ton–large steel structures and carry the assembled engines. Recently a few crashes have been occurred in carrying engines due to breaking down the lugs. Although the stability evaluation of the lifting lug has therefore been very important for safety, systematic design procedure of the lugs, which includes the structural analysis considering stability, has few reported. This paper describes the three dimensional finite element structural modeling for a lifting lug, the studies for determining the reasonable loading and boundary conditions, and the stability evaluation with the results of structural analyses. It should be very helpful for designing the other types of lifting lugs with safety.


Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1837 ◽  
Author(s):  
Martin Sotola ◽  
David Stareczek ◽  
David Rybansky ◽  
Jiri Prokop ◽  
Pavel Marsalek

This paper presents a new design procedure for production of a transtibial prosthesis bed stump by three-dimensional (3D) printing with topological optimization. The suggested procedure combines the medical perspective with finite element analysis and facilitates regaining the symmetry in patients with transtibial prosthesis, which leads to life improvement. The particular focus of the study is the weight reduction of the lower part of the bed stump, while taking into account its stiffness and load-bearing capacity. The first part of the work deals with the analysis of the subject geometry of the bed stump, which is usually oversized in terms of the weight and stiffness that are necessary for the current application. In the second part, an analysis of walking biomechanics with a focus on the impact and rebound phases is presented. Based on the obtained information, a spatial model of the lower part of the bed stump is proposed in the third phase, in which the finite element method is described. In the fourth part, the topological optimization method is used for reducing the structure weight. In the last part, the results of the designed model are analyzed. Finally, the recommendations for the settings of the method are presented. The work is based on the practical industry requirements, and the obtained results will be reflected in the design of new types of transtibial prosthesis.


2012 ◽  
Vol 215-216 ◽  
pp. 847-850
Author(s):  
Shou Jun Wang ◽  
Xing Xiong ◽  
Hong Jie Wang

In the condition of alternating impact ,the nut-supports subassembly is analyzed according to uncertainty of design parameters. Firstly, a three-dimensional (3-D) finite element (FE) model of the nut-supports subassembly is built and is meshed,and the constraints and loads are imposed.Secondly,the model of nut-supports was assembled using the software ANSYS to understand the stress distribution and various parts of the deformation of the nut-supports and its weak links in the harmonic forces.Finally,socket head cap screw has not enough pre-load in the condition of alternating impact and will be simplified.It is analyzed and checked whether it is cut or not; which provides the reference data for design and optimization of the wave maker.


2019 ◽  
Vol 7 (6) ◽  
pp. 187 ◽  
Author(s):  
Li ◽  
Hu ◽  
Song ◽  
Mao ◽  
Tian

Permanent magnet couplings (PMCs) are widely used in underwater propulsion because it can solve the deep-sea sealing problem effectively. In this paper, a new type of conical permanent magnet coupling (CPMC) is proposed, which is able to match the tail shape of the underwater vehicle and make full use of the tail space to increase pull-out torque capability. Based on the three-dimensional finite element method (3D-FEM), the electromagnetic characteristics of an initial model for CPMC are analyzed. In order to facilitate the design and optimization of CPMC, an equivalent three-dimensional (3D) analytical method for the pull-out torque calculation is presented, and its accuracy is verified by comparison with the 3D finite element results. Finally, the influence of design parameters such as half-cone angle, pole pair, pole arc coefficient and permanent magnet thickness on maximum pull-out torque and torque density of CPMC is analyzed, and a preliminary optimization model is obtained.


Author(s):  
Christian Aalburg ◽  
Alexander Simpson ◽  
Jorge Carretero ◽  
Tue Nguyen ◽  
Vittorio Michelassi

The design, analysis and optimization of a new stator concept for multistage centrifugal compressors using numerical methods is presented. The first objective was to further improve the performance of a well-optimized stage with a short vaneless diffuser, see Aalburg et al [1]. The second objective was to achieve a significant increase in the flow turning in the stator part. In order to achieve these goals an extension of the return channel vane upstream, over the U-turn bend, was considered. This design poses challenges that are quite different from those encountered for a conventional design. For example, a conventional vane angle distribution leads to lean angles across the bend that are not feasible from a manufacturing and aerodynamic perspective. In addition, conventional design tools for geometry generation were found to have limited applicability for this concept. To address these issues a geometry generator was developed that facilitated the design of three-dimensional across-the-bend type vanes with unconventional vane angle distributions. The geometry generator was based on an analytical design procedure similar to that outlined by Veress and Braembussche [2]. This procedure allows a desired loading distribution to be specified. In this paper the vane concept will be introduced, the development of the geometry generator will be outlined and the effect of varying design parameters will be considered. An optimized design will then be presented that outperformed the reference conventional design in terms of efficiency by up to one point across the operating range. This improvement was achieved despite a significantly higher vane loading.


Author(s):  
Shoichi Yoshida ◽  
Kazuyoshi Sekine ◽  
Tomohiko Tsuchida ◽  
Katsuki Iwata

The sloshing analysis of liquid storage tanks by the finite element method is basically categorized into two approaches, Lagrangian approach and Eulerian approach. In the Lagragian approach, the behavior of the fluid is expressed in terms of the displacements at nodal points. The advantage of the Lagragian method is that the computer code can be easily developed to modify an existing structural analysis code. The disadvantage is that some spurious modes are included in the vibration modes. The Lagrangian method is widely used in two- and three-dimensional problems. On the other hand, it has not been reported its applicability to the axisymmetric problem. This paper presents the applicability of the Lagragian method to the axisymmetric sloshing problem. The eigenvalue of an elemental stiffness matrix is analyzed in order to investigate the characteristics of the rotational stiffness to the compressibility of the fluid. As a result, this method is found to be difficult to apply to the axisymmetric problem if the equation of motion is directly solved using time integration. However, it gives the highly precise response solutions if the only sloshing modes are taken out and the modal analysis technique is used.


Author(s):  
Simon Kwong ◽  
Alan Paulley ◽  
Alex Bond

The computer code TRAFFIC incorporating three-dimensional (3-D) electrokinetic capabilities, coupled flow, transport and chemical speciation, using a finite element approach has been used to replicate published laboratory scale experiments [1, 2]. Two test cases have been presented using TRAFFIC with chemical speciation options and the Euler-Lagrangian transport formulation. The first of these (Case A with graphite anode) provided useful insights into the capabilities of the code to simulate realistic and complex problems, while the second (Case B with iron anode) closely reproduced the experimental results. It was also shown that the Euler-Lagrangian transport scheme was much better in coping with the steep chemical gradients, whereas the standard Euler scheme is less stable. Given the good results of these test cases, it is concluded that the code has been verified and partially validated.


2021 ◽  
Vol 11 (24) ◽  
pp. 11716
Author(s):  
Qingshun Bai ◽  
Mohamed Shehata ◽  
Ayman Nada ◽  
Zhongxi Shao

The article proposes a dynamic for design (DFD) procedure for a novel aperture grating tiling device using the multibody system (MBS) approach. The grating device is considered as a rigid-flexible MBS that is built primarily based totally at the load assumptions because of grating movement. This movement is utilized in many industrial applications, such as the compression of laser pulse, precision measuring instruments, and optical communication. A new design procedure of tiling grating device frame is introduced in order to optimize its design parameters and enhance the system stability. The dynamic loads are estimated based on the Lagrange multipliers that are obtained from the solution of the MBS model. This model is fully non-linear and moves in the three-dimensional space, and the relative movement of its bodies is restricted by the description of the constraints function in the motion manifold. The mechanism of the grating device is structurally analyzed in keeping with the dynamic conduct and therefore the generated forces. The symbolic manipulation as well as the computational work of solving the obtained differential-algebraic equations (DAEs) is carried out using MATLAB Symbolic Toolbox. Once the preliminary design has been attained, the stress behavior of the grating device is examined using the MATLAB FEATool Multiphysics toolkit, regarding system stability and design aspects. Moreover, the design was constructed in real life, and the movement has been verified experimentally, which confirms the effectiveness of the proposed procedure. In conclusion, the DFD procedure with trade-off optimization is utilized successfully to design the grating unit for maximum ranges of grating movements.


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