Modular Dynamic Model Assembly of Finite Element Models

Author(s):  
Zhen Ren ◽  
Clark J. Radcliffe

Analytical engineering design is a global activity requiring efficient global distribution of analytical models of dynamic physical systems through computer networks. Finite Element Method (FEM) models are used globally to analyze the response of physical systems assembled from physical components. FEM models from different physical component suppliers often have geometrically incompatible meshes. This geometric incompatibility of mesh node placement typically requires component internal details in the assembly process. The modular model assembly introduced in this paper does not require such component internal details. It assembles incompatible finite element component models fast and with accuracy comparable to traditional reformulation. The proprietary geometry and material component details are not revealed during the assembly. Modular model assembly can be used to assemble distributed component models through the internet in global engineering design. Dynamic examples are provided.

Author(s):  
Ashwini Gautam ◽  
Chris Fuller ◽  
James Carneal

This work presents an extensive analysis of the properties of distributed vibration absorbers (DVAs) and their effectiveness in controlling the sound radiation from the base structure. The DVA acts as a distributed mass absorber consisting of a thin metal sheet covering a layer of acoustic foam (porous media) that behaves like a distributed spring-mass-damper system. To assess the effectiveness of these DVAs in controlling the vibration of the base structures (plate) a detailed finite elements model has been developed for the DVA and base plate structure. The foam was modeled as a poroelastic media using 8 node hexahedral elements. The structural (plate) domain was modeled using 16 degree of freedom plate elements. Each of the finite element models have been validated by comparing the numerical results with the available analytical and experimental results. These component models were combined to model the DVA. Preliminary experiments conducted on the DVAs have shown an excellent agreement between the results obtained from the numerical model of the DVA and from the experiments. The component models and the DVA model were then combined into a larger FE model comprised of a base plate with the DVA treatment on its surface. The results from the simulation of this numerical model have shown that there has been a significant reduction in the vibration levels of the base plate due to DVA treatment on it. It has been shown from this work that the inclusion of the DVAs on the base plate reduces their vibration response and therefore the radiated noise. Moreover, the detailed development of the finite element model for the foam has provided us with the capability to analyze the physics behind the behavior of the distributed vibration absorbers (DVAs) and to develop more optimized designs for the same.


1975 ◽  
Vol 97 (3) ◽  
pp. 206-213 ◽  
Author(s):  
E. Friedman

Analytical models are developed for calculating temperatures, stresses and distortions resulting from the welding process. The models are implemented in finite element formulations and applied to a longitudinal butt weld. Nonuniform temperature transients are shown to result in the characteristic transverse bending distortions. Residual stresses are greatest in the weld metal and heat-affected zones, while the accumulated plastic strain is maximum at the interface of these two zones on the underside of the weldment.


2021 ◽  
Vol 263 (1) ◽  
pp. 5301-5309
Author(s):  
Luca Alimonti ◽  
Abderrazak Mejdi ◽  
Andrea Parrinello

Statistical Energy Analysis (SEA) often relies on simplified analytical models to compute the parameters required to build the power balance equations of a coupled vibro-acoustic system. However, the vibro-acoustic of modern structural components, such as thick sandwich composites, ribbed panels, isogrids and metamaterials, is often too complex to be amenable to analytical developments without introducing further approximations. To overcome this limitation, a more general numerical approach is considered. It was shown in previous publications that, under the assumption that the structure is made of repetitions of a representative unit cell, a detailed Finite Element (FE) model of the unit cell can be used within a general and accurate numerical SEA framework. In this work, such framework is extended to account for structural-acoustic coupling. Resonant as well as non-resonant acoustic and structural paths are formulated. The effect of any acoustic treatment applied to coupling areas is considered by means of a Generalized Transfer Matrix (TM) approach. Moreover, the formulation employs a definition of pressure loads based on the wavenumber-frequency spectrum, hence allowing for general sources to be fully represented without simplifications. Validations cases are presented to show the effectiveness and generality of the approach.


2021 ◽  
Author(s):  
Rashique Iftekhar Rousseau ◽  
Abdel-Hakim Bouzid ◽  
Zijian Zhao

Abstract The axial stiffnesses of the bolt and clamped members of bolted joints are of great importance when considering their integrity and capacity to withstand external loads and resist relaxation due to creep. There are many techniques to calculate the stiffnesses of the joint elements using finite element (FE) modeling, but most of them are based on the displacement of nodes that are selected arbitrarily; therefore, leading to inaccurate values of joint stiffness. This work suggests a new method to estimate the stiffnesses of the bolt and clamped members using FE analysis and compares the results with the FE methods developed earlier and also with the existing analytical models. A new methodology including an axisymmetric finite element model of the bolted joint is proposed in which the bolts of different sizes ranging from M6 to M36 are considered for the analysis to generalize the proposed approach. The equivalent bolt length that includes the contribution of the thickness of the bolt head and the bolt nominal diameter to the bolt stiffness is carefully investigated. An equivalent bolt length that accounts for the flexibility of the bolt head is proposed in the calculation of the bolt stiffness and a new technique to accurately determine the stiffness of clamped members are detailed.


Author(s):  
Youyi Bi ◽  
Jian Xie ◽  
Zhenghui Sha ◽  
Mingxian Wang ◽  
Yan Fu ◽  
...  

Customer preferences are found to evolve over time and correlate with geographical locations. Studying spatiotemporal heterogeneity of customer preferences is crucial to engineering design as it provides a dynamic perspective for a thorough understanding of preference trend. However, existing analytical models for demand modeling do not take the spatiotemporal heterogeneity of customer preferences into consideration. To fill this research gap, a spatial panel modeling approach is developed in this study to investigate the spatiotemporal heterogeneity of customer preferences by introducing engineering attributes explicitly as model inputs in support of demand forecasting in engineering design. In addition, a step-by-step procedure is proposed to aid the implementation of the approach. To demonstrate this approach, a case study is conducted on small SUV in China’s automotive market. Our results show that small SUVs with lower prices, higher power, and lower fuel consumption tend to have a positive impact on their sales in each region. In understanding the spatial patterns of China’s small SUV market, we found that each province has a unique spatial specific effect influencing the small SUV demand, which suggests that even if changing the design attributes of a product to the same extent, the resulting effects on product demand might be different across different regions. In understanding the underlying social-economic factors that drive the regional differences, it is found that Gross Domestic Product (GDP) per capita, length of paved roads per capita and household consumption expenditure have significantly positive influence on small SUV sales. These results demonstrate the potential capability of our approach in handling spatial variations of customers for product design and marketing strategy development. The main contribution of this research is the development of an analytical approach integrating spatiotemporal heterogeneity into demand modeling to support engineering design.


Author(s):  
Gabriela Alor-Saavedra ◽  
Francisco Alejandro Alaffita-Hernández ◽  
Beatris Adriana Escobedo-Trujillo ◽  
Oscar Fernando Silva-Aguilar

This work makes a comparative study of two methods to determine deflection in steel beams: (a) Theoretical and (b) Finite element. For method (a) the solution of the differential equation associated with the modeling of the deflection of a beam is found, while for method (b) a simulation is made in Solidworks. Both methods are compared with experimental data in order to analyze which of the methods presents less uncertainty and show the usefulness of the theoretical part in the modeling of physical systems.


2005 ◽  
Vol 127 (1) ◽  
pp. 33-39 ◽  
Author(s):  
M. Huang ◽  
X. Niu ◽  
P. Shrotriya ◽  
V. Thompson ◽  
D. Rekow ◽  
...  

This paper presents the results of recent experimental and finite element studies of contact damage in model dental multilayered systems with equivalent elastic properties to those of crown/join/dentin layers that are found in dental restorations. Subsurface radial cracks are observed to form after Hertzian indentation fatigue loading. In order to explain the possible failure mechanisms, the viscous deformation of the foundation (dentinlike ceramic filled polymer) and epoxy join layers are measured. Finite element and analytical models are then developed in an effort to explain the observed contact-induced deformation of the composite multilayered system. Our results suggest that: viscous deformation of the join and foundation layers can give rise to increased tensile stresses in the top elastic layers (glass or zirconia); defects at the bottom of the top layers (induced by grinding steps before crown attachment) are also shown to promote ratcheting phenomena that can lead to stress build-up in the top layers; and viscous flow of the cement can cause the subcritical crack growth in the dental ceramics.


Author(s):  
Andrea Mazzurco ◽  
James L Huff ◽  
Brent K Jesiek

Students in global service-learning and similar programs frequently encounter substantial social, cultural, political, and ethical differences when working with project partners in different countries and regions. Neglecting such differences can lead to project failures and/or disempowered communities. In response to these challenges, educational resources have been developed to teach students to think about how the people, social structures, and other contextual factors associated with projects can affect, and be affected by, students’ designs. Yet, there remains a scarcity of valid and reliable instruments to evaluate the effectiveness of such interventions. The purpose of this study is create a theoretically and empirically grounded instrument, the Energy Conversion Playground (ECP) design task, that is able to provide a meaningful and robust assessment of an individual’s ability to identify salient technical and non-technical considerations when approaching an engineering design task situated in a developing country context. We present the scenario and an accompanying rubric that was first developed inductively from student responses to the scenario (specifically 449 discrete items from 93 ECP design tasks submitted by students who attended a Global Engineering Design Symposium). Further development of the rubric involved deductive grounding in relevant literature. To demonstrate the sensitivity of ECP design task to changes in students’ thinking, we also performed comparative analysis of responses from a subset of the students (n=37) who completed the same instrument both before and after participating in the GEDS.


2009 ◽  
Vol 76 (6) ◽  
Author(s):  
I. Quintana Alonso ◽  
N. A. Fleck

The tensile fracture strength of a sandwich panel, with a center-cracked core made from an elastic-brittle diamond-celled honeycomb, is explored by analytical models and finite element simulations. The crack is on the midplane of the core and loading is normal to the faces of the sandwich panel. Both the analytical models and finite element simulations indicate that linear elastic fracture mechanics applies when a K-field exists on a scale larger than the cell size. However, there is a regime of geometries for which no K-field exists; in this regime, the stress concentration at the crack tip is negligible and the net strength of the cracked specimen is comparable to the unnotched strength. A fracture map is developed for the sandwich panel with axes given by the sandwich geometry. The effect of a statistical variation in the cell-wall strength is explored using Weibull theory, and the consequences of a stochastic strength upon the fracture map are outlined.


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