Papers by Keyword: Damage Prediction

Abstract: This paper takes the seismic performance of the existing building evaluation in Wuhan, analysis of the existing building on the seismic performance, and extract a certain characteristic parameters for quick retrieval and identification, proposed the idea of the of earthquake damage prediction database, build and improve the based information of the construction earthquake damage prediction, establish a fast city buildings earthquake damage prediction system.

Abstract: Abstract. The application of modern high strength low alloyed steels (HSLA) and advanced high strength steels (AHSS) for structural and safety relevant components in the automotive industry offers the advantage of combining low specific weight with high material strength. Typical manufacturing processes for these steel grades are bending and cutting operations. The forming and cutting potential of these innovative steel grades is different to conventional steels as the process and the damage behaviour is changing. In bending operations cracks occur at the outer bending edge, whereas in cutting operations delamination can appear at the sheared edge. These damages, even though they are small, can initiate the component to fail. For a reliable use of such materials in industrial application a method for the process design is essentially needed. In particular, damages have to be predicted at an early stage. In industrial application damage is detected by a trial-and-error approach causing significant work and a high failure rate. A system for an offline assessment of the risk of failure is unknown so far. In the scope of this work, a method is presented to describe the damaging behaviour of both, bending and cutting operations, by theoretical metamodels. In order to generate a database experiments were carried out using different high strength steels. The main influence factors have been varied, such as the rolling direction, the punch-to-die clearance and the cutting contour in the cutting operation. The bending was investigated using an air-bending process varying the bending angle, the bending radius and the rolling direction. To calculate further sampling points a finite element model has been developed and validated against the experimental data. The damage criterion of Lemaître has been applied. The necessary parameters were determined by reverse identification by means of the major strain for the bending operation and by the punch force-punch stroke curve for the cutting operation. To build up a system for the prediction of the damage the gained data basis was approximated by mathematical functions. An error analysis was carried out showing good accordance. In doing so, a metamodel for the occurrence of damages could be established. The functions are implemented in a software tool which allows the user to determine the failure probability for a given parameter set.

Abstract: Back-propagation method (BP method) is the supervised learning algorithm that is the most widely and successfully used in feed forward network nowadays. This paper dealt with the penetration and blasting experimental data by BP Neural networks, including of the influence of the velocity and attack angles to damage of multilayer medium penetration and blasting. Through handling of the experimental data by the BP Network system, coupled effects of quantity of explosive and buried depth can be uncoupled. The curves of infundibular crater radius vs. quantity of explosive and infundibular crater depth vs. buried depth of explosive was given. Base on computing results, it is shown that the neural networks method can be used to predict the damage of multilayer medium penetration and blasting.

Abstract: Based on the technology such as remote sensing(RS), geographic information system(GIS), 3D simulation, and damage prediction, the simulation technology of earthquake disaster scene (STEDS) is the important content of digital disaster reduction and has important research value, which can be used to decision support, virtual training, and popular science education and so on. The general idea of STEDS is introduced in this paper and the key technologies to simulate an earthquake disaster scene livingly are analyzed. Taking a real city for example, the disaster scene of building blocks is completed, which take different colors as the signs of different damage levels under earthquake effect. The 3D building model bases are established by 3D modeling technology, which include 3D intact building models and the damage ones with different damage levels. Based on the replacement rules of models, the preliminary disaster scene of 3D damage building models is realized.

Abstract: A promising approach to handling low ductile aluminium alloys in a forming process is forming under superimposed hydrostatic pressure. The influence of superimposed hydrostatic pressure on the flow stress as well as on the formability for various hydrostatic pressures and temperatures was analysed [15, 3, and 7]. By increasing the formability of the workpiece, larger local plastic strains could be achieved. The results reveal highly increased formability at superimposed pressure of 85 MPa for workpieces from thermosetting alloy AlSi1MgMn (EN AW 6082) in comparison to those from self-hardening alloy AlMg4.5Mn0.7 (EN AW 5083). As a general tendency, the self-hardening alloys show a lower increase in formability when forged under superimposed pressure. But additionally, a charge-dependent influence of macro- and micro defects on the crack resistance was detected for alloy AlMg4.5Mn0.7. By evaluating damage models in finite element models the damage occurring in cold forming processes under superimposed hydrostatic pressure was predicted.

Abstract: The original structure stress state of No. zero frame of TB200 aircraft is analyzed by finite element method. The stress and the reasons of the crack on the frame are determined. The numerical analysis results fit well with the actual damage of the frame, and the finite element analysis model is verified to be reliable. The stress state of the damaged frame structure is analyzed, which shows that the undamaged frame structure must be reinforced. The reinforce plan for the undamaged frame structure is given. The reinforced frame structure is analyzed by finite element method. The stress state and the residual strength of the reinforced frame structure are given. It is showed that the reinforce plan causes an obvious descent of the frame stress. The load is mainly distributed on the reinforcement of the No. zero frame. The residual static strength of the reinforced structure is higher than the original structure. The possible secondary damage position and mode of the reinforced structure are predicted.

Abstract: Recently, author had presented that impact force history of composite laminates subjected to low-velocity impact could be well analyzed using linearized contact law instead of the modified Hertzian contact law. If the linearized contact law concept is applied in impact response analysis, the impact problem can be transformed as a general structural analysis problem, so general purpose FEM software can be used in this kind of impact response analysis. In the present study it will be shown that impact damage, specially delamination area, as well as impact response can be well analyzed using the linearized contact law concept. In order to accurately predict delamination area, geometrical nonlinear analysis considering large deflection effect of plate has been performed and thermal stress analysis to consider thermal residual strain induced in curing process has been performed. Also, a proper failure criterion for delamination estimation has been used. In this failure criterion, in-situ strength values, obtained through matrix crack onset analysis have been used. Finally, analytically predicted delamination areas have been compared with experimental results. It shows that this analytical procedure can well predict delamination area of composite laminates subjected to the low-velocity impact.

Abstract: Ceramic is prone to engender surface/subsurface crack damage layer because of great grinding force and high brittle. Prediction of crack damage of ground ceramic is important for design and assessment of grinding process. In this paper, an investigation for surface/subsurface crack damage of ground ceramic is introduced. Depth of crack damage layer can predicted by calculating crack propagation balance size and a predicting model of crack damage layer depth is obtained.