Development of Differential Quadrature Related Generalized Methods, Discrete Element Analysis Methods and EDQ Based Time Integration Methods

Development of differential quadrature related generalized methods, discrete element analysis methods and EDQ based time integration methods has been carried out the last few years. The related numerical algorithms are summarized and presented. Numerical results are also presented.

Analysis for Vehicle Interior Noise Using Helmholtz Resonator

In this paper the reduction analysis of the so-called ‘booming noise’, which occurs due to the resonance of a vehicle cabin, is tried to carry out by using the finite element method. For the reduction method a Helmholtz resonator, which is well known in the field of acoustics, is attached to a vehicle cabin. The resonance frequency of a Helmholtz resonator can be varied by adjusting the length of its throat. The simply shaped Helmholtz resonator is set up to the back of the cabin according to the resonance frequency of the cabin and the frequency response of the sound pressure at a driver’s ear position is calculated by using the finite element method. It is confirmed that the acoustical characteristics of the cabin is changed largely by attaching the resonator and the sound quality is quite varied. The resonance frequency of the resonator can be considered to follow the acoustical characteristics of the cabin by using an Origami structure as a throat. So, in the future the analysis by using an Origami structure Helmholtz resonator should be performed.

Case Study of Temperature Analysis Performed on a 45-inch Diameter Heat Exchanger Flange

This paper presents an overview of thermal and mechanical analysis performed on the tubesheet joint of a 45 inch diameter feed/effluent heat exchanger to determine the effects of temperature on the joint operation. Two methods of analysis are used, a new analytical approach and Finite Element Analysis (FEA). The analysis determined a potential problem with the operation of the joint in the intended service and a method of improvement was proposed. Some pitfalls of the methods of analysis, for both the analytic method and FEA, are presented. The comparison between the analytic approach and FEA clearly outlined the advantages of each method in determining the operability of heat exchanger joints.

Consequences of the German TA Luft for Bolted Flange Connections and Valves in Industrial Plants

The high grade performance of gaskets for bolted flange connections in terms of TA Luft and VDI guideline 2440 assumes the fulfilment of the following requirements: Long-term suitability of the gasket particularly with regard to the exposure to the operating temperature and the medium; this requires the investigation of the long-term behaviour, e.g. according to DIN 28090-2 and DIN 28090-3 The design of flange connections (strength and tightness proof) on the basis of realistic gasket characteristics determined experimentally, e. g. according to DIN 28090-1 or prEN 13555 Compliance with the specific leakage rate of 10-4 mbar 1 / (s·m) in a type test at 1 bar test pressure. Similar requirements are effective for packings of stuffing boxes, in which the type test is carried out under more intensive boundary conditions compared to the flange connections: real operating pressure and stem strokes. In the frame of a research project sponsored by the German chemical industry a choice of gaskets were tested which cover all gasket types in the European gasket standard EN 1514 part 1 to 7. The gasket types were classified in view of their high grade performance potential. Similar investigations and analyses were carried out for standard packings for stuffing boxes. These results and their consequences are presented. In addition to the explicitly mentioned requirements in VDI 2440 further requirements should be seen as important in view of the assurance of high grade performance: Quality control during gasket production This can be ensured by manufacturers quality management and by compliance with requirements of corresponding quality standards, e.g. DIN 28091 (an European quality standard (prEN 14772) for gaskets is in preparation) Controlled assembly, which is necessary to realise the design assembly bolt load with limited scattering High grade performance proof of gaskets, more correctly of gasketed bolted flange connections has to be regarded as a complex matter in opposition to common interpretations and involves more than just the compliance with a certain leakage rate criterion of a special type test.

Forced Response of Continuous System With Hysteresis Loop Characteristics: System With Quadrilateral Hysteresis Loop Characteristics

This paper deals with steady-state response of a continuous system with collision characteristics. Considering the energy loss in a collision, an analytical method of approximate solution for the continuous system with symmetrical hysteresis loop characteristics is presented. The resonance curves of nonlinear response obtained from approximate solution are shown as discontinuous line, and are discussed the phenomenon.

Utilizing Direct Tension Squirter Indicators in Industrial Applications

In the world of critical bolting applications there is a need for achieving correct gasket loads. The new technology of Direct Tension Squirter Washers is designed to show visual indication when 60% of yield for a B7 bolt has been reached. Torque wrench inconsistencies have caused many gasket failures. There are many times the incorrect gasket load has been applied to bolted joints resulting in joint failure. The root cause of these failures range from bad calculation of friction for anti seize to damaged threads. DTSW ensures the bolts have reached the correct bolting load resulting in a properly loaded gasket that will not be doomed for failure. This paper will review the DTSW Technology and how it can be applied in Industry applications. It will discuss the inaccuracy of torque wrench technology in today’s industrial bolting environment. The paper will also highlight show the DTSW technology ease of use compared to typical Indicator washers that require feeler gauges.

A Forward Explicit Algorithm With Automatic Error Control for a Cyclic Thermoviscoplastic Coupled With Damage Model of Sn-Pb Solder

A self-correcting forwards gradient time integration procedure is formulated for the integration of a unified viscoplastic constitutive coupled with damage model for a eutectic solder alloy under cyclic fatigue loading. The procedure has been implemented numerically in the commercial finite element (FE) code ABAQUS (Version 6.2) via the user-defined material subroutine. The stress (constitutive) Jacobian explicit solution is derived. Schemes of the algorithm are verified by a series of numerical examples, including (1) Single-element simulations for uniaxial test, tensile creep, and fatigue simulations to reveal the optimum combination of the user-specified tolerance and the prescribed load step size to obtain a desired accuracy at a minimum cost. (2) Two three-dimensional analyses for monotonic tensile loading and fatigue loading were conducted for a miniature specimen of solder to show the capability of the proposed procedure to deal with thermomechanical loading. (3) Simulation of a shear notched specimen under monotonic loading was compared with the test to illustrate the ability of this algorithm for the specimen that has a serious damage region. The numerical examples illustrated that the explicit algorithm as well as empirical rule for adaptive time increment is effective for simulating cyclic thermoviscoplastic behavior of solder. The research can be applied to the simulation of viscoplasic behavior and fatigue life of softening materials.

Elastic Modulus Adjustment Improved Convergement Schemes Using Variable Local Constraints

Elastic modulus adjustment procedures (EMAP) have been employed to determine limit loads of pressure components. On the basis of linear elastic Finite Element Analysis (FEA) with non-hardening elastic properties, i.e., by specifying spatial variations in the elastic modulus, numerous set of statically admissible and kinematically admissible distributions can be generated, and both lower and upper bounds on limit loads can be obtained. Some methods such as the classical, r-node and mα methods provide limit loads on the basis of partly-converged distributions, whereas the accuracy of linear matching procedures rely on fully converged distributions. In this paper, a criterion for establishing the degree of convergence of EMAP is developed, and a simple procedure for achieving improved convergence is described. The procedure is applied to some practical pressure component configurations.

A New Embedded-Zone Method on Computation of the Transverse Elastic Properties of Fiber-Reinforced Composites

There are many methods on computation of transverse elastic properties of unidirectional fiber-reinforced composites when using the finite element method, such as three-dimension model, two-dimension plane strain model, unit cell model, etc[1]. But unit cell models could be used only when the fibers are arrayed regularly. The computations of three- and two-dimension plane strain models are tremendous when many fine fibers are spread randomly in the matrix so that the properties of block of composite must be computed. The paper proposes a new embedded-zone method to compute the transverse elastic properties for a block of fiber-reinforced composites containing a great amount of fibers embedded in the matrix stochastically while using very little computational work compared with three- and two-dimension plane strain model. The transverse elastic modulus and shear modulus of unidirectional fiber-reinforced composites are computed.

Determine Weight of Hot Metal Car Using Strain Gage Method

In certain situations, train car containers that carry hot metal have been overfilled, which necessitated the replacement of very costly car parts. Therefore, it is desirable to predict the amount of fluid needed at all times in order to know when to divert the flow of molten steel from the car. This study showed that the level of fluid in a container can be controlled even when the amount of fluid inside the container is not visible. When strain gages are effectively installed they can be used to continuously calculate the weight of a system as the strain increases, although only the final total weight is of concern. Strain gages can be positioned in safe locations on the spanner bolster of a hot metal car. The gages are installed such that the thermal and axial strains cancel out, ultimately leaving only the value for the weight of the loaded car. Once the gages are installed, they are calibrated when the system is full. For all subsequent loading periods, the strain gages report a linear strain increasing until it is equal to the original full calibration value. This then signals the operator to divert the flow of steel. If the inside of the container deteriorates over time, the strain that governs the shutoff remains the same although the fluid level is slightly lower. In the event of skull (leftover steel in the container), the maximum strain remains the same and the final volume is lower than the initial calibration condition. The objective in all cases is to avoid overflow of fluid from the car. This investigation showed that the amount of fluid in a train car that carries molten steel can be known at all times during the filling process. It is supported with manual calculations, finite element analyses, and laboratory experiments.