Finite element modeling analysis

Finite element model analysis simulating the thermal cycle tests demonstrated that the top coat spallation of both types of coating is caused by the buckling driven by delamination due to the transient large in-plane compressive stress development immediately after initiate heating. 

In many industrial halls, conduction inro the ground is a major factor for heat loss. Therefore, an adequate modeling of the floor slab and the underlying, thermally active, soil is very crucial for reliable simulation resuirs. In this case, the soil model in the TRNSYS model was established using results from an additionally performed finite-element program analysis. 

Another well-established area of mechanical finite-element analysis is in the motion of the structures of the human middle ear (Figure 9.3). Of particular interest are comparisons between the vibration pattern of the eardrum, and the mode of vibration of the middle-ear bones under normal and diseased conditions. Serious middle-ear infections and blows to the head can cause partial or complete detachment of the bones, and can restrict their motion. Draining of the middle ear, to remove these products, is usually achieved by cutting a hole in the eardrum. This invariably results in the formation of scar tissue. Finite-element models of the dynamic motion of the eardrum can help in the determination of the best ways of achieving drainage without affecting significantly the motion of the eardrum. Finite-element models can also be used to optimise prostheses when replacement of the middle-ear bones is necessary. 

In the present paper we extend our analysis of the experimental results obtained from this small deformation regime and we show that the result found by Reissner for the deformation of shallow spherical caps represents an excellent analytical approximation for the interpretation of the measurements. This result is varified by finite element modelling (FEM) and by experimental variation of the force probe geometry and radius as well as wall thickness of the studied capsules. This result is also applicable for other capsule deformation measurements, since it is independent of the specific Young s modulus. Furthermore, we report on speed dependent measurements that indicate the glassy nature of PAH/PSS multilayers. 

Finite element modeling is also useful in failure analysis. The method has been successfully applied in failure analysis. An example involving the stressed condition with maximum stress concentration in cloverleaf radius is shown in Figure 2.29. Another example of finite element modeling applied to distorted transformer housing due to internal overpressurization has been cited in Figure 2.17. 

The accuracy of the test procedure was validated by room temperature testings of two to three fracture specimens of each material. Additional load data, which were obtained through the bottom load transducer, were used to check the accuracy of the finite element modeling of the load train. A KRAKf gauge at the remaining ligament of the prenotched bar was used to check the master curve which related the crack extension history with the COD data at room temperature. Details of this validation analysis are described in Ref. 57. 

We present recent results on the analysis of the interaction between plasticity and crazing at the tip of a preexisting crack under mode I loading conditions. Illustrations of the competition between these mechanisms are obtained from a finite element model in which a cohesive surface is laid out in front of the crack. 

FINITE ELEMENT ANALYSIS Finite element model... 

A two-dimensional finite-element modelling was carried out by the IRSN/EMP to analyse HM effects during excavation of a circular hole in a homogeneous, isotropic, porous elastic medium. The finite-element coupled codes VIPEF (mechanic) and HYDREF (hydraulic) was used for this HM analysis (Tijani, 1996). 

Sound knowledge of the joint behavior is required for a successful design of bonded joints. To characterize the bonded joint, the loading in the joint and the mechanical properties of the substrates and of the adhesives must be properly defined. The behavior of the bonded joint is investigated by finite element (FE) analysis methods. While for the design of large structures a cost-efficient modeling method is necessary, the nonlinear finite element methods with a hyperelastic material model are required for the detailed joint analysis. Our experience of joint analysis is presented below, and compared with test results for mass transportation applications. 

We also had to be proficient at design and here our capabilities in Finite Element Analysis were important. We use finite element stress analysis for design of offshore structures for oil production, for pipelines and for a range of process plant. By working closely with materials scientists who understand the properties of fibre reinforced materials it was possible to build models of the blocker door and predict load paths and deflections as required by the customer. These analyses formed the basis for determining the shapes and fibre directions of the preforms. 

Stress and strength modelling finite element (FE) analysis... 

To measure load distribution, standard aerospace bolts were fitted with strain gauges. Both shear and axial load could be measured. A three-dimensional finite element model with linear elastic material properties was developed for calculation of load distribution prior to initiation of material failure and comparison with instm-mented bolt results. Model details are similar to those of the single-bolt model above, with a full contact analysis being performed for all bolts, washers and holes. 

A future trend in composite bolted joint design is the use of more advanced continuum damage mechanics approaches to model joint failure, so that non-linear shear behaviour and gradual stiffness degradation can be implemented. An important element of joint failure is delamination, and many efforts are being undertaken to implement delamination in finite element models. However, for bolted joints analysis this poses many problems due to the large number of delamination interfaces in thick laminates. 

To produce the seismic analysis model for the reactor internal structures, the lumped-mass modeling technique is used From the 3-dimensional finite element model of KALIMER reactor internal structures, the detail local stiffness analyses are performed to construct the lumped-mass seismic analysis model The seismic analysis and evaluation of KALIMER are presented through the modal analysis, the seismic time history analvsis, and the equivalent seismic stiess analysis Table 3 shows the natural frequencies of the reactor structures resulted from the modal analysis for the seismic analysis model shown in Fig 13... 

Hemez, F. M. and Farhat, C. Structural damage detection via a finite element model updating methodolt y. International Journal of Analytical and Experimental Modal Analysis 10(3) (1995), 152-166. 

The Vessel System, including the support subsystem, is analyzed using the NSSS finite-element model and response spectra input generated by the plant seismic analysis discussed in Section 3.7.2. This three-dimensional finite-element model is based on the Vessel System arrangement and is shown in Figure 3.7-6. The analysis is performed using the ANSYS computer code and the analysis procedures discussed in Section 3.7.3.1.1. (Ref. 11)... 

Further detailed finite-element modeling and analysis are performed to determine vessel stresses at critical locations such as the vessel/support interfaces and vessel/crossduct intersections. The seismic response loads from the NSSS model are used as input to these models. 

Depending on the structural information produced in the Step 1) static and dynamic analysis of the most representative bridges will be performed under the estimated service load distribution from train traffic and other heavy time-dependent loads. For this purpose, a three-dimensinal finite-element model of each most representative bridge, which is capable to reflect the actual structural properties with reasonable accuracy, will be used along with the COSMOS Structural Analysis Code (Cosmos 1990). In this way it will be possible to... 

Since little damage was observed within the laminate in the course of the experiment, it was assumed that the diffusion process in the laminate essentially obeyed Tick s law given by equation [12.3]. A two-dimensional plane strain finite element model of the laminate was generated and the NOVA-3D finite element program was used to solve for the moisture uptake and stresses within the laminate. Based on characterization test data, the temperature dependent through-thickness diffusivity definition used in this analysis is given by ... 

To gain a better understanding of the burr formation process and to be able to predict burr formation, the finite element method analysis can be applied. In Leopold et al. (2005), the state of research and future developments in modeling and simulation of burr formation are highlighted. 

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