Using the Simple Structural Beam (SSB) Model to Optimize and Analyze Automotive Structures for Bending Stiffness and Natural Frequency

2014 ◽  
Author(s):  
Ian Wood ◽  
Ahmad Barari ◽  
Ebrahim Esmailzadeh
Keyword(s):  
Natural Frequency ◽  
Early Stage ◽  
Dynamic Properties ◽  
Weight Ratio ◽  
Bending Stiffness ◽  
Beam Model ◽  
Beam Elements ◽  
Fundamental Natural Frequency ◽  
Stage Of Development ◽  
Vehicle Structure

When designing a vehicle structure, an optimum design is desired because the structure has a significant impact on its performance. The structure impacts other components in the vehicle as well. The designing process usually involves complex iteration. Analyses must be done at the early stage of the vehicle’s development (body-in-white) to minimize the amount of parameter changes needed during the late stage of development. Successfully implementing this strategy reduces the time and cost required to develop an effective vehicle structure. A method known as Simple Structural Surfaces can be used to model the vehicle structure as several planar sheets, as well as determine the forces in each sheet. The downside of using this method is that by using it, determining the deflections in the structure is difficult. In order to eliminate this difficulty, the vehicle is modeled as several beam elements instead. In this method, a finite element method is used to numerically solve for the deflections, reaction forces, and internal loading on each element of the structure. This Simple Structural Beam model can be adapted to allow optimization of the static property of the structure bending stiffness. Dynamic properties of the vehicle structure are also examined through vibration analysis, by determining the fundamental natural frequency of the structure. Vibration also has a large impact on the structure’s performance. The goal of the research is to obtain a design that will optimize the static and dynamic properties of the vehicle’s structure. In the beam elements, the parameters involved are the length, orientation, cross-sectional area, and moment of inertia. The optimizing process is automated and determines the beam dimensions with largest stiffness to weight ratio. The fundamental natural frequency calculated must be distant from the frequency of the engine, as resonance is also a concern for structural performance. Resonance occurs when the natural frequency of the system is equal to the frequency of a connecting component. This increases the amplitude of vibration significantly and is undesirable for any structural design.

Analysis and Optimization of Automotive Structure’s Bending Stiffness Using Beam Elements

2012 ◽  
Author(s):  
Steven Tebby ◽  
Ahmad Barari ◽  
Ebrahim Esmailzadeh
Keyword(s):  
Bending Stiffness ◽  
Major Drawback ◽  
Cross Sectional ◽  
Beam Elements ◽  
Complex Interactions ◽  
Design Changes ◽  
Vehicle Structure ◽  
Reaction Forces ◽  
Numerical Finite Element

Optimum design of vehicle’s structure is an important task in its development. The structure of a vehicle plays complex interactions with the other vehicle components and has significant impact on the performance of the vehicle. Structural design is usually completed by a complex iterative process. The design changes at late design stages effect many other parameters in the design of vehicle. Therefore, it is highly valuable for designers to employ simple but effective analyses at the early design stages. One method of analysis is using Simple Structural Surfaces. This method utilizes planar sheets to model the vehicle structure and allows the determination of the forces in each sheet. The major drawback of this method is its inability to easily determine deflections in a structure. To overcome this drawback a method that uses beam elements to represent the vehicle structure has been developed. This method uses a numerical finite element method and is able to determine unknown deflections and reaction forces as well as the internal loading on each member. This method can also be readily adapted to allow for parametric optimization for bending stiffness. The parameters associated with each beam element are the length, orientation and the beam characteristics of beams’ cross-sectional area and moment of inertia. An automated process is developed that manipulates some of these parameters to develop a structure that will have the greatest bending stiffness.

Automatic Generation of Component Modes for Rotordynamic Substructures

1989 ◽  
Vol 111 (1) ◽  
pp. 6-10 ◽  
Author(s):  
S. H. Crandall ◽  
N. A. Yeh
Keyword(s):  
Timoshenko Beam ◽  
Dynamic Models ◽  
Dynamic Properties ◽  
Automatic Generation ◽  
Component Mode Synthesis ◽  
Beam Equation ◽  
Beam Model ◽  
Exact Integration ◽  
Beam Elements ◽  
Loading Patterns

Dynamic analysis models are customarily employed in turbomachinery design to predict critical whirling speeds and estimate dynamic response due to loads imposed by unbalance, misalignment, maneuvers, etc., Traditionally these models have been assembled from beam elements and been analyzed by transfer matrix methods. Recently there has been an upsurge of interest in the development of improved dynamic models making use of finite element analysis and/or component mode synthesis. We are currently developing a procedure for modelling and analyzing multi-rotor systems [1] which employs component mode synthesis applied to rotor and stator substructures. A novel feature of our procedure is a program for the automatic generation of the component modes for substructures modelled as Timoshenko beam elements connected to other substructures by bearings, couplings, and localized structural joints. The component modes for such substructures consist of constraint modes and internal modes. The former are static deflection shapes resulting from removing the constraints one at a time and imposing unit deflections at the constraint locations. The latter have traditionally been taken to be a subset of the natural modes of free vibration of the substructure with all constraints imposed. It has however been pointed out [2] that any independent set of geometrically admissible modes may be used. We take advantage of this and employ static deflections under systematically selected loading patterns as internal modes. All component modes are thus obtained as static deflections of a simplified beam model which has the same span and same constraints as the actual substructure but which has piecewise uniform dynamic properties. With the loading patterns we employ, all modes are represented by fourth order polynomials with piecewise constant coefficients. We have developed an algorithm for the automatic calculation of these coefficients based on exact integration of the Timoshenko beam equation using singularity functions. The procedure is illustrated by applying it to a simplified system with a single rotor structure and a single stator structure. The accuracy of the procedure is examined by comparing its results with an exact analytical solution and with a component mode synthesis using true eigenfunctions as internal modes.

Long-term monitoring of dynamic characteristics of high-rise and super high-rise buildings using strong motion records

2021 ◽  
Vol 13 (12) ◽  
pp. 168781402110672
Author(s):  
Yinfeng Dong ◽  
Hui Tian ◽  
Man Zhang ◽  
Lejun Wei
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Dynamic Properties ◽  
Epicentral Distance ◽  
Damping Ratio ◽  
Focal Depth ◽  
High Rise ◽  
Fundamental Natural Frequency ◽  
Term Monitoring

Seismic behavior of a structure is directly related to its dynamic characteristics, which include natural frequency, damping ratio, and mode shape. This study focuses on the long-term monitoring of dynamic characteristics of six selected target structures. The covariance-driven stochastic subspace identification (SSI) approach is used to estimate the fundamental natural frequency and damping ratio of target buildings based on long-term motion records in order to examine the temporal variation of dynamic properties. The fundamental natural frequency and damping ratio variations over time are first discussed. It is found that the fundamental natural frequency of some structures reduces dramatically after the 2011 Tohoku Earthquake, accompanied by a rise in damping ratio. Then, regression analysis is used to assess the relationship between dynamic characteristics and ground motion parameters (Peak ground acceleration (PGA), magnitude, focal depth, and epicentral distance) and structural response (root mean square acceleration, maximum response amplitude). It is discovered that the identified natural frequency has no clear correlation with the focal depth, a slight negative correlation with the epicentral distance, and a strong negative correlation with the magnitude and PGA. The root mean square acceleration and the maximum response amplitude are negatively correlated to the target buildings’ natural frequencies. Finally, the influence of environmental factors on dynamic properties is investigated.

Using Simple Structural Beam Model to Optimize for Bending Stiffness and Vibration in Automotive Structures

2014 ◽  
Author(s):  
Ian Wood ◽  
Ahmad Barari ◽  
Ebrahim Esmailzadeh
Keyword(s):  
Past Research ◽  
Bending Stiffness ◽  
The Body ◽  
Optimized Design ◽  
Beam Model ◽  
Acceptable Solution ◽  
Substantial Impact ◽  
Beam Elements ◽  
Overall Performance ◽  
Comfortable Ride

Prior research has shown that the design of a vehicle’s structure has a substantial impact on its overall performance under static loading [1], since the structure affects other components of the vehicle aside from the body. In addition to the past research, dynamic loading is added in this paper as a parameter for design. Bending stiffness and weight are still important factors to consider, since a stiffer structure (higher stiffness) means longer life and stability. A lighter vehicle translates to better fuel economy, lower cost and higher performance. Simple Structural Beams are used to model the structure, where several beam elements are used in the setup. The cross-section properties are analyzed to determine the structure’s weight, bending stiffness, natural frequency and amplitude of vibration. In order to find an acceptable solution, the design must avoid the possibility of resonance. Vibration has a large impact on a structure’s performance, the larger the amplitude, the more uncomfortable the ride is. The goal of this research is to obtain a design that will optimize for vibration and for bending stiffness and weight. The purpose of the optimized design is to provide the best performance and most comfortable ride to the driver. The optimization process is automated iteratively and solves for the beam dimensions that correspond to the optimized parameters.

Study on the Stiffness Loss and the Dynamic Influence on Rotor System of the Bolted Flange Joint

2014 ◽  
Author(s):  
Cun Wang ◽  
Dayi Zhang ◽  
Xiaobin Zhu ◽  
Jie Hong
Keyword(s):  
Finite Element ◽  
Mechanical Characteristics ◽  
Dynamic Properties ◽  
Bending Stiffness ◽  
Rotor System ◽  
Structural Parameter ◽  
Beam Model ◽  
Flange Joint ◽  
Bolted Flange ◽  
Stiffness Loss

The bolted flange joint is a kind of widely used joint structure in the rotor system. Its discontinuous mechanical characteristics result from the existing of the contact surface, which will slide and deform when the spool deforms. As a consequence, the joint’s stiffness is always smaller than that of fixed configuration, which affects rotor’s stiffness distribution and the rotor’s dynamics further. The objective of this study is to investigate the mechanical characteristics of the bolted flange joint, the affecting factors and the influence on rotor’s dynamics. According to the characteristics of structure and mechanical state, using the existing equivalent axial spring-bending beam model to describe the tension and compression stiffness of bolted flange joint section, then the bending stiffness model of whole bolted flange joint is established based on that. The results show that there is a significant effect of the bolted flange joint on the local stiffness of the rotor, the loss of local bending stiffness reach a high level when the number of bolts is few. The mathematical description between stiffness loss and structure size, load and assembling condition is obtained through the analytical results. A bolted flange joint simulation model, taking the characteristics of the contact into account, is built by the nonlinear finite element method. The trends of numerical results agree with the analytical conclusion, and show the stiffness of bolted flange joint is smaller than that of the fixed configuration. The stiffness of bolted flange joint decreases a small amount with the increasing moment. When the number and the pretension force increases, the stiffness increases nonlinearly. Based on the mechanism of stiffness loss, the equivalent stiffness is used to replace the fixed configuration stiffness on the location of bolts in finite element model of high pressure rotor system. The results of dynamic analysis shows that the stiffness loss has a greater impact on bending modes than the rigid modes while the static analysis shows that the stiffness loss has a small negatively effect on clearances. The study shows that, the stiffness loss of bolted flange joint has a close relationship with the load and assembling conditions. The results show the effectiveness in controlling the mechanical and dynamic properties of the rotor with bolted flange joints by careful adjusting of structural parameter, load parameter and assembling parameter during designing.

scholarly journals Development of Conceptual Design for Electric Bus Body Structure Using Simple Structural Surface Method

2021 ◽  
Vol 4 (1) ◽  
pp. 22-28
Author(s):  
Ismoyo Haryanto ◽  
◽  
Achmad Widodo ◽  
Ibrahim Satya ◽  
Gunawan Dwi Haryadi ◽  
...  
Keyword(s):  
Conceptual Design ◽  
Early Stage ◽  
Body Structure ◽  
Stage Of Development ◽  
Surface Method ◽  
Electric Bus ◽  
Vehicle Structure ◽  
Structural Surface ◽  
Bus Body ◽  
Method Model

An optimum design for a vehicle structure is always desired because the structure can significantly affect the vehicle's performance. However, some complex iterations are usually involved in the designing process. The objective of the present study is to implement the Simple Structural Surfaces (SSS) method for analyzing electric bus body structure that can reduce complexity in the stage of conceptual design. The SSS method model the vehicle structure as several planar sheets and determine the forces in each sheet. Implementing the SSS method at the early stage of the vehicle's development can minimize the number of parameter changes needed during the late stage of development. The results showed that compared with the results obtained from FEM, the SSS method gave the maximum stress value on the chassis in good accordance. Yet, the downside of using this method is that determining the deflections in the structure becomes a little bit complicated. Successfully implementing this strategy can reduce the time and cost required to develop an effective vehicle structure.

The Application of UX Research in New Energy Vehicle Innovation

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Menghan TAO ◽  
Ning XIAO ◽  
Xingfu ZHAO ◽  
Wenbin LIU
Keyword(s):  
Early Stage ◽  
Rapid Expansion ◽  
The Other ◽  
Innovative Product ◽  
Stage Of Development ◽  
New Energy ◽  
New Energy Vehicle ◽  
The One ◽  
New Energy Vehicles ◽  
Degree Of Innovation

New energy vehicles(NEV) as a new thing for sustainable development, in China, on the one hand has faced the rapid expansion of the market; the other hand, for the new NEV users, the current NEVs cannot keep up with the degree of innovation. This paper demonstrates the reasons for the existence of this systematic challenge, and puts forward the method of UX research which is different from the traditional petrol vehicles research in the early stage of development, which studies from the user's essence level, to form the innovative product programs which meet the needs of users and being real attractive.

scholarly journals Beam Theory of Thermal–Electro-Mechanical Coupling for Single-Wall Carbon Nanotubes

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 923
Author(s):  
Kun Huang ◽  
Ji Yao
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Beam Theory ◽  
Bending Stiffness ◽  
Single Wall Carbon Nanotubes ◽  
Beam Model ◽  
Euler Beam ◽  
New Model ◽  
Mechanical Coupling ◽  
Electrostatic Fields

The potential application field of single-walled carbon nanotubes (SWCNTs) is immense, due to their remarkable mechanical and electrical properties. However, their mechanical properties under combined physical fields have not attracted researchers’ attention. For the first time, the present paper proposes beam theory to model SWCNTs’ mechanical properties under combined temperature and electrostatic fields. Unlike the classical Bernoulli–Euler beam model, this new model has independent extensional stiffness and bending stiffness. Static bending, buckling, and nonlinear vibrations are investigated through the classical beam model and the new model. The results show that the classical beam model significantly underestimates the influence of temperature and electrostatic fields on the mechanical properties of SWCNTs because the model overestimates the bending stiffness. The results also suggest that it may be necessary to re-examine the accuracy of the classical beam model of SWCNTs.

scholarly journals Learning health systems in primary care: a systematic scoping review

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Danielle M. Nash ◽  
Zohra Bhimani ◽  
Jennifer Rayner ◽  
Merrick Zwarenstein
Keyword(s):  
Primary Care ◽  
Quality Improvement ◽  
Health Systems ◽  
Scoping Review ◽  
Early Stage ◽  
Point Of Care ◽  
The United States ◽  
Stage Of Development ◽  
Integrated Health ◽  
Google Search

Abstract Background Learning health systems have been gaining traction over the past decade. The purpose of this study was to understand the spread of learning health systems in primary care, including where they have been implemented, how they are operating, and potential challenges and solutions. Methods We completed a scoping review by systematically searching OVID Medline®, Embase®, IEEE Xplore®, and reviewing specific journals from 2007 to 2020. We also completed a Google search to identify gray literature. Results We reviewed 1924 articles through our database search and 51 articles from other sources, from which we identified 21 unique learning health systems based on 62 data sources. Only one of these learning health systems was implemented exclusively in a primary care setting, where all others were integrated health systems or networks that also included other care settings. Eighteen of the 21 were in the United States. Examples of how these learning health systems were being used included real-time clinical surveillance, quality improvement initiatives, pragmatic trials at the point of care, and decision support. Many challenges and potential solutions were identified regarding data, sustainability, promoting a learning culture, prioritization processes, involvement of community, and balancing quality improvement versus research. Conclusions We identified 21 learning health systems, which all appear at an early stage of development, and only one was primary care only. We summarized and provided examples of integrated health systems and data networks that can be considered early models in the growing global movement to advance learning health systems in primary care.

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