scholarly journals Validation of a New Aluminum Honeycomb Crush Model With Dynamic Impact Tests

2007 ◽  
Author(s):  
Terry Hinnerichs ◽  
William Scherzinger ◽  
Mike Nielsen ◽  
Tom Carne ◽  
Eric Stasiunas ◽  
...  
Keyword(s):  
Finite Element ◽  
Rate Sensitivity ◽  
Element Model ◽  
Test Results ◽  
Dynamic Impact ◽  
New Approach ◽  
Test Parameters ◽  
Aluminum Honeycomb ◽  
Impact Simulations ◽  
Constitutive Parameters

This paper describes a process for validating a new constitutive model for large, high strain-rate deformation of aluminum honeycomb, called the Honeycomb Crush Model (HCM). This model has 6 yield surfaces that are coupled to account for the orthotropic behavior of the cellular honeycomb being crushed on-axis and off-axis. The HCM has been implemented in the transient dynamic Presto finite element code for dynamic impact simulations. The HCM constitutive parameters were identified based on Presto finite element models that were used to simulate uniaxial and biaxial crush tests of 38 lb/ft3 aluminum honeycomb and reported in an earlier paper. This paper focuses on validating the HCM in the Presto code for application to impact situations that have honeycomb crush velocities up to 85 ft/sec. Also, a new approach for incorporating rate sensitivity into the model is described. A two-stage energy absorber with integrated aluminum honeycomb is described as the configuration for dynamic impact validation experiments. The test parameters and finite element model will be described along with the uncertainty quantification that was done and propagated through the model. Finally, correlation of model predictions and test results will be presented using an energy based validation metric.

A New Aluminum Honeycomb Constitutive Model for Impact Analyses

2004 ◽  
Author(s):  
Terry Hinnerichs ◽  
Michael Neilsen ◽  
Wei-Yang Lu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Test Data ◽  
Element Model ◽  
Constitutive Parameter ◽  
Model Parameters ◽  
Test Configuration ◽  
Aluminum Honeycomb ◽  
Impact Simulations ◽  
Orthotropic Behavior

A new constitutive model for large deformation of aluminum honeycomb has been developed. This model has six yield surfaces that are coupled to account for the orthotropic behavior of the cellular honeycomb being crushed on-axis and off-axis. Model parameters have been identified to fit uniaxial and biaxial crush test data for high density (38 lb/ft3) aluminum honeycomb. The honeycomb model was implemented in the transient dynamic Presto finite element code for dynamic impact simulations. In order to extract useful constitutive-parameter information from crush tests, each test configuration and process is simulated with a Presto finite element model to analyze the non-uniform strain/crush behavior within the test samples. Results from the suite of honeycomb crush tests that were used to calibrate the new honeycomb model are shown. Also, the honeycomb model’s predictions are compared with test data and with the older Orthotropic Crush Model predictions.

Design of Static Test Model for Three-Tower Cable-Stayed Self-Anchored Suspension Composed Bridge

2011 ◽  
Vol 243-249 ◽  
pp. 1528-1535
Author(s):  
Yu Zhao ◽  
Yong Jun Zhou ◽  
Jing Sun ◽  
Jin Tao Tang ◽  
Xu Li
Keyword(s):  
Complex System ◽  
Finite Element ◽  
Element Model ◽  
Test Model ◽  
Test Results ◽  
Static Test ◽  
Whole Process ◽  
Aesthetic Appearance ◽  
Load Carrying ◽  
Novel Structures

Cable-stayed self-anchored suspension composed bridges have novel structures and aesthetic appearance with complex system and difficulty for design and construction. In order to acquire a better knowledge of the load-carrying capability of this type of bridges, based on a real bridge and the theory of abnormal similarity, a full-bridge scaled down(1:20) test model was built to simulate the whole process of construction. The test results were preferably fit the theoretical calculation value. It can be seen that the design of the bridge was reasonable, and the accuracy of the calculation of finite element model was verified at the same time. The test and the related results can be used as the reference for the test and design of the similar bridges.

Dynamic Impact Measurements on Crossings, in Free Floating and In-Situ Conditions

2014 ◽  
Author(s):  
M. A. Boogaard ◽  
A. L. Schwab ◽  
Z. Li
Keyword(s):  
Finite Element ◽  
Condition Monitoring ◽  
Impact Loading ◽  
Dynamic Behaviour ◽  
Element Model ◽  
Mode Shapes ◽  
Dynamic Impact ◽  
In Situ Test ◽  
In Situ Conditions

As vibration based condition monitoring requires a good understanding of the dynamic behaviour of the structure, a good model is needed. At the TU Delft a train borne monitoring system is being developed which currently focusses on crossings. Crossings are prone to very fast degradation due to impact loading. In this paper a finite element model of a free floating frog is presented and validated up to a 100 Hz using dynamic impact measurements. The mode shapes of the free floating frog are then also compared to some preliminary results from an in-situ test. This comparison shows that the in-situ frequencies can be up to twice the free floating frequency.

scholarly journals Biaxial estimation of biomechanical constitutive parameters of passive porcine sclera soft tissue

2021 ◽  
Author(s):  
Zwelihle Ndlovu ◽  
Dawood Desai ◽  
Thanyani Pandelani ◽  
Harry Ngwangwa ◽  
Fulufhelo Nemavhola
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Model ◽  
Test Data ◽  
Element Model ◽  
Finite Element Models ◽  
Anisotropic Model ◽  
Material Models ◽  
Material Parameters ◽  
Constitutive Parameters

This study assesses the modelling capabilities of four constitutive hyperplastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine’ slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96 %. The polynomial (anisotropic) model gave the best correlation of 98 %. However, the estimated material parameters varied widely from one test to another such that there would be needed to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be needed to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters thereby making it an easier option for application of its material parameters to a finite element model and also requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy more influenced by the fiber-related properties than the background material matrix related properties.

Seismic behaviour of prestressed high-strength concrete piles under combined axial compression and cyclic horizontal loads

2018 ◽  
Vol 22 (5) ◽  
pp. 1089-1105 ◽  
Author(s):  
Xizhi Zhang ◽  
Sixin Niu ◽  
Jia-Bao Yan ◽  
Shaohua Zhang
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
High Strength Concrete ◽  
High Strength ◽  
Element Model ◽  
Test Results ◽  
Seismic Behaviour ◽  
Strength Concrete ◽  
Concrete Piles ◽  
Concrete Pile

In order to simulate the seismic behaviour of the prestressed high-strength concrete piles under working state, six full-scale prestressed high-strength concrete piles were tested under combined axial compression and cyclic horizontal loads. Different axial compression levels and prestressing levels of prestressed tendons were studied in this test programme. The failure mode, bending resistance, displacement ductility, stiffness degradation and energy dissipation of the prestressed high-strength concrete piles under different loading scenarios were measured and analysed. Test results indicated that the axial compression ratio and prestressing level of prestressed tendon significantly influenced the seismic performance of prestressed high-strength concrete piles. Theoretical models were developed to predict cracking, yielding and ultimate bending resistances of the prestressed high-strength concrete pile under combined compression and bending. Finite element model was also developed to simulate the ultimate strength behaviour of the prestressed high-strength concrete pile under combined compression and flexural bending. The accuracies of the theoretical and finite element model were checked through validations of their predictions against the reported test results.

Rotor optimization for the improvement of ultrasonic motor performance

2019 ◽  
Vol 233 (19-20) ◽  
pp. 7089-7100 ◽  
Author(s):  
Zhangfan Xu ◽  
Sisi Di ◽  
Song Pan ◽  
Lei Chen ◽  
Weiqing Huang
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Shell Structure ◽  
Motor Performance ◽  
Thin Shell ◽  
Element Model ◽  
Ultrasonic Motor ◽  
Comsol Multiphysics ◽  
New Approach ◽  
The Relationship

The rotor deformation of an ultrasonic motor is an important factor affecting its performance. However, little research focuses on the relationship between the rotor deformation and motor performance. This paper provides an approach to improve the ultrasonic motor's output properties by changing the rotor's size from the view of proper rotor deformation and better stress distribution on the interface. First, a thin shell structure is introduced to study the deformation of the rotor. A finite element model of the motor is built in COMSOL Multiphysics software for the contact analysis of the stress distribution. Then, the optimized ranges of parameters are determined by simulation. Frictional experiments are conducted to verify the feasibility of the rotor under the optimized size. Finally, the performance experiments of a stator corresponding to different sizes of rotor are carried out. The experimental results show that the speed, the power and the efficiency of the optimized rotor are all increase. These results prove the effectivity of the new approach to improving the performance of the ultrasonic motor.

scholarly journals Research on Spillover Effects for Vibration Control of Piezoelectric Smart Structures by ANSYS

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Xingjian Dong ◽  
Zhike Peng ◽  
Wenming Zhang ◽  
HongXing Hua ◽  
Guang Meng
Keyword(s):  
Finite Element ◽  
Closed Loop ◽  
Parametric Design ◽  
Smart Structures ◽  
Element Model ◽  
Spillover Effects ◽  
Smart Structure ◽  
Control Laws ◽  
Actual Structure ◽  
New Approach

To control vibration of a piezoelectric smart structure, a controller is usually designed based on a reduced order model (ROM) of the system. When such a ROM based controller operates in closed loop with the actual structure, spillover phenomenon occurs because the unmodeled dynamics, which are not included in ROM, will be excited. In this paper, a new approach aiming at investigating spillover effects in ANSYS software is presented. By using the ANSYS parametric design language (APDL), the ROM based controller is integrated into finite element model to provide an accurate representation of what will happen when the controller is connected to the real plant. Therefore, the issues of spillover effects can be addressed in the closed loop simulation. Numerical examples are presented for investigating spillover effects of a cantilever piezoelectric plate subjected to various types of loading. The importance of considering spillover effects in closed loop simulation of piezoelectric smart structures is demonstrated. Moreover, the present study may provide an efficient method especially beneficial for preliminary design of piezoelectric smart structure to evaluate the performance of candidate control laws in finite element environment considering spillover effects.

Shock environment design for space equipment testing

2016 ◽  
Vol 231 (6) ◽  
pp. 1154-1167 ◽  
Author(s):  
OMF Morais ◽  
CMA Vasques
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Test System ◽  
Test Apparatus ◽  
Shock Test ◽  
Shock Testing ◽  
Test Parameters ◽  
Shock Environment ◽  
Definition Of

The main specification in the verification by testing of space hardware vulnerability to shock excitations is the shock response spectrum. Although it compiles the most relevant information needed to describe the overall shock environment characteristics, shock testing still poses various difficulties and uncertainties concerning the suitability and operation of the shock test system used, and the adequate definition of the underlying test parameters. The approach followed from the interpretation of typical shock testing specifications to the development, validation, and characterization of the developed shock test system, including the definition and design of the relevant parameters influencing the attained shock environment, is described in this paper. The shock testing method here presented consists of a pendular in-plane resonant mono-plate shock test apparatus where the structural response of the ringing plate depends upon well-defined controllable parameters (e.g. impact velocity, striker shape, mass, and contact stiffness), which are parametrically determined to achieve the target shock environment specification. The concept and analytical model of two impacting bodies are used in a preliminary analysis to perform a rigid body motion analysis and contact assessment. A detailed finite element model is developed for the definition of the ringing plate dimensions, analysis of the plate dynamics and virtual shock testing. The assembled experimental apparatus is described and a test campaign is undertaken in order to properly characterize and assess the design and test parameters of the system. The developed shock test apparatus and corresponding finite element model are experimentally verified and validated. As a result of this study, a reliable finite element modeling methodology available for future shock test simulation and prediction of the experimental results was created, being an important tool for the adjustment of the shock test input parameters for future works. The developed shock test system was well characterized and is readily available to be used for shock testing of space equipment with varying specifications.

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