Papers by Keyword: Parametric Model

Abstract: This work presents the design of a parametric Kelvin structure in which the relative density of the geometry can be varied by adjusting three parameters: cell diameter, cell wall thickness and cell chamfer radius, the structure consistsing of a tessellation of hollow truncated octahedral. The developed model was evaluated in terms of compressive stiffness for the case of a rigid polyurethane foam of 0.256 relative density. Three models were analyzed in order to determine the influence of geometric characteristics on mechanical properties: a model that presented no chamfer a model that presented a medium-sized chamfer and a model that presented a large chamfer. A mesh convergence study was performed which analyzed the results in terms of accuracy and time expenses for three element sizes for both linear and quadratic elements. Due to the orthotropic nature of the model, its response on both possible loading directions was investigated. Simulation results were compared with experimental results and yielded accurate results for one loading direction, when using the material properties for solid polyurethane described in literature.

Abstract: To investigate factors affecting contact interface pressure distribution in bolted joint, a parametric model was established by ANSYS APDL language in this paper. The contact pressure distribution on bolted joint interface was obtained through interpolating and revising contact interface forces. It is observed that the position of peak interface pressure is between the edge of bolt hole and the edge of bolt head. The contact pressure linearly changes with the bolt load while the distribution trend and radius remain unchanged. When the total thickness of clamped members is fixed, the contact pressure distribution varies from concentrated to uniform with the increasing member thickness ratio, and the maximum contact radius is reached while the member thickness is equal. When one clamped member thickness is fixed, increasing the other’s thickness can also reduce the contact pressure concentration, but the effect gradually weakens. Increasing bolt diameter can slightly increase the absolute contact radius but decrease the normalized contact radius. The inclusion of a washer under the nut can slightly promote interface clamping.

Abstract: Design of experiment (DoE) is a set of practical recipes and theoretical assumptions leading to the optimization of the technological process and/or the stabilization of its output quality. Practically, all the DoE approaches assume the normality of a random noise and the quasi-linearity of models taken from the general linear model (GLM) class. It allows to use traditional least-square methodology to identification of a model parameters and their confidence intervals. It gives usually sufficient results but completely fails if the model is not from GLM class or a random noise has not a normal distribution. The solution for such problems is the bootstrap approach, a resampling method based on Monte Carlo strategies. This paper tries to answer a question how many repetitions should be made to estimate parameters of the prediction model with sufficient accuracy.

Abstract: Typical design of experiments (DoE) approach to the response surface problem applies the polynomials with at most the second order terms. It is correct due to the Taylor’s theorem when the variability of input variables is sufficiently small. Unfortunately, the variability bound of a designed experiment is planned with high uncertainty about the investigated object’s behavior. If the response of the object has a large curvature then model quality indicators (residuals normality, lack of fit, significance of terms) appear to be unacceptable. In such a case, polynomial terms with the order higher than second should be applied. The paper describes the RSM model with the fourth order terms identified for relationship between settings of a meat tumbler machine (input variables) and the Warner-Bratzler shear force (output variable).

Abstract: This research proposes a parametric model to be applied in the process of green building design that integrates particular city land use regulations and provide visual feedback to the architect about the setback information, profiles, and Floor Area Ratio that could be integrated with their solutions. In addition, through the use of real-time geospatial inputs, parametric models will add specificity to the site coordinate accounting, neighboring parcels, and land use designation in the solution. Two parallel streams simultaneously investigated, one that checks the local conditions of a single plot and a more global urban conditions considered.

Abstract: Simulation-based building performance allows detailed assessment of energy consumption in buildings. This paper presents an energy simulation via HB method of an office building model and outlines the significance and influence of design, construction and HVAC system on the energy consumption. The research was conducted through HB dynamic simulation method which allows flexibility of the thermal model and variability of elements and HVAC system properties, resulting in an energy simulation to outline the major criteria in qualitative enhancement. The findings indicate the influence of each factor on the total energy consumption regarding to the comfort maintenance of users.

Abstract: In this work, a study of the influence of the cutting parameters on superficial quality of dry-turned UNS A97075 test bars has been carried out. The superficial quality has been evaluated trough the arithmetical average roughness, Ra. In addition, the evolution of Ra as a function of the axial machining length has been analyzed. In order to do this, a set of machining tests has been performed under different combinations of cutting speed and feed. The experimental data have revealed a high sensitivity to change of Ra with feed, whereas this sensitivity is lower with cutting speed. On the other hand, a tendency to decrease Ra with the axial machining length has been found. Finally, an experimental prediction model for Ra has been developed. This model allows predicting the value of Ra as a function of the cutting parameters and the machining time.

Abstract: Cutting forces are one of the inherent phenomena and a very significant indicator of the metal cutting process. The work presented in this paper is an investigation of the prediction of these parameters in slotting processes of UNS A92024-T3 (Al-Cu) stacks. So, cutting speed (V) and feed per tooth (f_z) based parametric models, for experimental components of cutting force, F(f_z,V) have been proposed. These models have been developed from the individual models extracted from the marginal adjustment of the cutting force components to each one of the input variables: F(f_z) and F(V).

Abstract: For decreasing the stress and displacement of pile clamping mechanism of hydraulic static pile drivers in the process of pile driving, optimizing the pile clamping mechanism and improving quality of pile driving, the working principle of pile clamping and pile driving were introduced briefly. The parametric model of pile clamping mechanism was constituted in ANSYS; the main parameters of the model were set. The command-flow was programmed with APDL standing for ANSYS parametric design language. And then the serialization simulation analysis of pile clamping mechanism was achieved; the cloud diagram of Von Mises stress and the maximal Von Mises stress and displacement vector sum of pile clamping mechanism were elicited. The simulation results were analyzed.

Abstract: One of the possibilities how to increase the efficiency of the deployment of tools for design, simulation and preparing of manufacturing technology is linking engineering applications with external tools, providing data for digital model managing. Strategically correctly designed parametric model can be managed by externally provided information. This paper provides examples of three methods using external data. Presented methods are validated during the use in industrial practice and in the preparation of technical staff at secondary schools, colleges and universities of engineering focus. The main objective of the deployment of presented methods is the acceleration of creation of virtual prototypes digital data of varying complexity while maintaining the accuracy of the corresponding geometric and functional requirements for the final product. At the same time these methods can be used to streamline transfers between different data formats of designer data and to allow interventions into the structure of the model without the use of a particular design engineering applications.