Finite Element Methods

Computer modelling and simulation of the the quadcopter body had been investigated in this article. For the modelling of a body the Fusion 360 software had been used. In the first stage the geometrical form was taken a simple prismatic form. After analysing the load-stress distribution using finite element method an optimized construction of a body have been designed.

As Additive Manufacturing (AM) continue to evolve, components can be improved to reduce their overall weight while increasing efficiency. In racing in particular, there is a strong incentive for maximally optimized parts, as sometimes only a few seconds decide between victory and defeat. This paper shows the advantages of Additive Manufacturing in the production of components with complex geometries such as aerodynamic spoilers for vehicles. Here, AM enables the use of bionically inspired structures which make these parts stiff and light at the same time while meeting the load profile (e.g. for the core structure of a wing). Therefore, structure and flow analysis based on the aerodynamic load is carried out and the results converted into algorithms to particularly compress the inner structure in highly stressed areas. The algorithm is a proprietary development that combines data from various software and applies the results to given component geometries simulating bionic structures.

Despite the generally inferior clinical performance of acetabular prostheses as compared
to the femoral implants, the causes of acetabular component loosening and the extent to
which mechanical factors play a role in the failure mechanism are not clearly understood
yet. The study was aimed at investigating the load transfer and bone remodelling around
the uncemented acetabular prosthesis.
The 3-D FE model of a natural right hemi-pelvis was developed using CT-scan data. The
same bone was implanted with two uncemented hemispherical acetabular components,
one metallic (CoCrMo alloy) and the other ceramic (Biolox delta), with 54 mm outer
diameter and 48 mm bearing diameter. The FE models of the implanted pelvis
(containing ~116000 quadratic tetrahedrals) were generated using a submodelling
approach, which were based on an overall full model of implanted pelvis (containing
~217600 quadratic tetrahedrals) acted upon by hip joint force and twenty one muscle
forces. The apparent density (ρ in g cm-3) of each cancellous bone element was calculated
using linear calibration of CT numbers of bone, from which the Young’s modulus (E in
MPa) was determined using the relationship, E = 2017.3 ρ2.46 [1].
Implant-bone interface
conditions, fully bonded and debonded with friction coefficient μ = 0.5, were simulated
using contact elements. Applied loading conditions consist of two load cases during a gait
cycle, corresponding to 13% and 52% of the walking cycle. Fixed constraints were
prescribed at the pubis and at the sacroiliac joint. The bone remodelling algorithm was
based on strain energy based site-specific formulation [2]. The FE analysis, in
combination with the bone remodelling simulation, was performed using ANSYS FE
software.
The predicted changes in peri-prosthetic bone density were similar for the metallic and
the ceramic implant. For debonded implant-bone interface, stress shielding led to ~20%
reductions in bone density at supero-anterior, infero-anterior and posterior part of the
acetabulum (Fig. 1). However, bone apposition was observed at the supero-posterior part
of the acetabulum, where implantation led to ~60% increase in bone density (Fig. 1). The
effect of bone resorption was higher for the fully bonded implant-bone interface, wherein
bone density reductions of 20 – 50% were observed in the cancellous bone underlying the
implant (Fig. 1), which is indicative of implant loosening over time. However,
implantation led to an increase in bone density around the acetabular rim for both the
interface conditions (Fig. 1). These results are well corroborated by the earlier studies
[3,4]. Implantation with a ceramic component resulted in 2 – 7% increase in bone density
at supero-posterior part of the acetabulum as compared to the metallic component, for the
debonded interface condition. Considering better wear resistant properties and absence of
metal ion release, results of this study suggest that the ceramic component might be a
viable alternative to the metallic prosthesis.

Currently, there are a lot of powerful FEM packages which are used for different types of analysis of structures. However, using these softwares for assessment of seismic safety and strengthening of historical masonry buildings are envolved with some problems. Complex building geometry, low information about physical and mechanical properties of materials, lack of precise information about composing material of internal parts of thick elements, prohibition of execution of destructive tests on these buildings, consumpsion of considerable cost and time for analysis process are some of the problems for engineers and researchers working professionally on numerical modelling of historical buildings.
    Simplified Kinematic Limit Analysis (SKLA) is a powerful method for the analysis of historical buildings. Historical masonry buildings subjected to earthquake show in most cases local failure mechanisms rather than global failure mechanisms due to the lack of integrity of structure. For this reason, SKLA method is recommended for strengthening of historical masonry buildings in Italian O.P.C.M.3431 ordinance. Simplified kinematic limit analysis of a structure includes a series of limit analysis that check the stability of different specific failure mechanisms involving the equilibrium of macro-elements. This kind of analysis stemed from the fact that structural masonry constructions normally collapse due to a local failure mechanism. Applied rules in this method are based on virtual work principle. Four overturning and four in plane collapse mechanisms were devised and analyzed for seismic safety assessment of structure in SKLA method.
    In this paper, this method (SKLA) capability for assessing the seismic safety of Tabriz Alisha Citadel is investigated. For this, the results of analysese of this building by two methods of SKLA and FEM are compared. The comparison of the results of two methods has shown acceptable accordance. High analysis speed and being free of precise mechanical properties of the buildings material are main features of SKLA method. However, tracing the magnitude of stresses and deflections in different points, revealing collapse time and sequence of fracture of walls are main features of FEM. It seems that the SKLA can be utilized as a high speed and low cost tool for primary assessment of seismic safety of masonry buildings.
    From that result, it was concluded that the structure is not safe. While the gravity capacity of the structure is high, its lateral resistance to equivalent static loading is not enough.

The purpose of the study is to predict deformation of a weldment in dissimilar laser welding process of low carbon steel and stainless steel 304 based on numerical and computation simulation approach. Different characterization of material on heat expand result influent distortion direct. The temperature rated effect of welding process direct to low carbon steel that caused heat expansion value of stainless steel 304 less than low carbon steel. Computer simulation or finite element model (FEM) used to understand the response and behavior of weldment during the welding process. Thermal expansion of weldment often leads to thermal stress in the weldment. The resulting temperature distribution, heat flux distribution and structural response under arc current welding constitute knowledge in assuring design success of welding product. The calculation results used FEM shows heat rated direct to low carbon area and high distortion occur there. Stainless steel with low expansion value has slow heat rated expansion and low distortion.