Papers by Keyword: Finite Element (FE) Simulation

Abstract: Glass fiber reinforced polymers (GFRPs) are becoming increasingly important in aerospace, construction, and automotive industries due to their potential for weight reduction, high strength, and excellent fatigue resistance. The failure mechanisms of GFRPs are influenced by factors such as strain-rate, frequency, stress state, and temperature. However, existing constitutive models have predominantly focused on characterizing the material's behavior under quasi-static conditions, potentially limiting their accuracy when applied to situations involving higher strain rates. This study employs explicit dynamics finite element analysis to examine the impact of high strain rates on the dynamic compressive behavior of glass fiber reinforced polymers (GFRPs) in an ABAQUS CAE environment using the Split Hopkinson Pressure Bar (SHPB) experimental setup. The mechanical response of the [0/90]₁₆ GFRP laminate system is characterized using the orthotropic elasticity material model and Hashin Damage Criteria is used to model the damage properties. Based on stability of total model energy, mesh convergence test was conducted across various mesh sizes to obtain the optimal mesh size for validating the developed FE-model. The simulation results highlight a notable increase in the compressive stress of the GFRP, rising from 200 MPa to 663 MPa as the strain rate increases from 596 s^-1 to 1743 s^-1. These results have shown the strain rate sensitivity of GFRPs and offer valuable insights for the prospective design and application of GFRP composites.

Abstract: In order to solve the problem of efficient and accurate tool change in vibration system, horn with a conical hole and a center via hole which connects tool is proposed. In connection with the shape of the horn, an equivalent model of the horn is built up. Based on the transmission matrix method, the frequency equation and magnification factor of the horn is deduced. And the finite element method was employed to verify the derived formulas. Compared the simulation results with the theoretical results, the derived formulas can be applied to design the complex horn.

Abstract: Semi-solid forming processes can lead to hot cracking. The process parameters responsible for hot cracking are still not well known. The paper aims at contributing to a better understanding of the process parameters promoting this phenomenon. Finite element simulations of thixoextrusion tests were carried out to analyse the thermal and mechanical fields. Comparisons between experimental and calculated results enable to propose a hot cracking criterion.

Abstract: In this paper, I use the finite element software abaqus to simulate the damage form of masonry walls in the case of force. Advantages and disadvantages of various simulation methods are fully considered. Masonry walls are considered homogeneous isotropic continuum,was built by using integrated model. And I adopt concrete damage model to define material properties. The results showed that the model in this paper well simulated the failure characteristics of the wall.

Abstract: In incremental sheet forming (ISF) the tool moves along the specified trajectory and deforms the sheet in to required shape. In the present paper incremental forming process is simulated using explicit finite element software LS-DYNA. The computational time for the simulation of ISF is very long due to long tool paths used in the process. To overcome this problem time scaling and mass scaling are used in the present paper. The effect of time scaling and mass scaling on forming forces, plastic strain, internal energy, kinetic energy, thickness distribution and computational time is studied. A continuously varying wall angle conical frustum is simulated for this study. Extra deep drawn steel, which is most commonly used in automotive applications, has been used as a blank material. Thickness distribution obtained with different mass and time scaling factors is compared with experimentally measured thickness distribution.

Abstract: With the continuous development of the ultrasonic detection technology, ultrasonic time of flight diffraction (TOFD) method has been widely applied. The paper investigated the TOFD technique in the detection of natural defects. TOFD detection experiment is established in Lab. The finite element analysis simulation of A-scan signal and ultrasonic TOFD technique in the detection of the longitudinal arrangement of pores defects within the weld specimen transmission are studied. The feasibility and correctness of the finite element analysis model are verified by comparing the experimental signals with the simulation signals.

Abstract: Progressive failure process of adhesive joint under cyclic loading is of particular interest in this study. Such fatigue failure is described using damage mechanics with the assumed cohesive behaviour of the adhesive joint. Available cohesive zone model for monotonic loading is re-examined for extension to capture cyclic damage process of adhesive joints. Damage evolution in the adhesive joint is expressed in terms of cyclic degradation of interface strength and stiffness. Mixed-mode fatigue fracture of the joint is formulated based on relative displacements and strain energy release rate of the interface. A power-law type variation for each of these cohesive zone model parameters with accumulated load cycles is assumed in the presence of limited experimental data on cyclic interface fracture process. The cyclic cohesive zone model (CCZM) is implemented in commercial finite element analysis code and the model is validated using adhesively bonded 2024-T3 aluminium substrates with epoxy-based adhesive film (FM73M OST). The CCZM model is then examined for cyclic damage evolution characteristics of the adhesive lap joint subjected to cyclic displacement of Δδ = 0.1 mm, R=0 so as to induce shear-dominant fatigue failure. Results show that the cyclic interface damage started to initiate and propagate symmetrically from the both overlap edges and degradation of interface strength and stiffness started to accumulate after 0.5 cycles of displacement elapsed. The predicted results are consistent with the mechanics of relatively brittle interface failure process.

Abstract: Steel belt of buffer structure with plastic deformation, employed in vertical shaft lifting as a overwind protection device, is simple and of convenient maintenance. Steel strip bends large deformation and wear when passing through buffer structure, which will damage the buffer strip, and reduce its initial strength as well. This paper focuses on the influence of steel strip thickness and pressure roller diameter on the deformation of steel belt by applying the finite element simulation, to provide theoretical basis for reliability design of the steel strip.

Abstract: In this study, a method based on finite element (FE) simulation was proposed for characterizing simultaneously residual stresses (RS) and accumulated plastic strain (PP) induced by shot peening process. Through a series of simulations of instrumented indentation, contour plots of several parameters, as maximum load, contact hardness and contact stiffness, were computed. By superposing them pair-wisely, RS and PP mixed together could be characterized simultaneously. In order to verify the method, several simulations with different combinations of RS and PP were performed. Results showed that the method is promising but remains to be tested on experimental acquisitions.

Abstract: An experimental campaign of compression tests, differential thermal analysis (DTA), differential scanning calorimetry (DSC), dilatometry and microstructure analysis has been performed, as well as the identification of the material data set for finite element (FE) analysis of bimetallic rolls. This article numerically investigates the stress and strain fields after the cooling stage and it checks their effect on the subsequent heat treatment step. As bimetallic rolls have a different material for core and shell, the effect of the roll size and the shell thickness on residual stresses is also studied.