Description of joint constraints in the floating frame of reference formulation

Korkealaakso, Pasi; Mikkola, Aki; Rantalainen, Timo; Rouvinen, Asko

doi:10.1243/14644193jmbd170

Cited by 19 publications

(16 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, rotation modes can be used in the description of constraint equations applied to rotational degrees of freedom (Korkealaakso et al, 2009). Rotational modes are used here to connect sub-models to large-scale models.…”

Section: The Floating Frame Of Reference Formulationmentioning

confidence: 99%

Sub-modeling approach for obtaining structural stress histories during dynamic analysis

2013

View full text Add to dashboard Cite

Abstract. Modern machine structures are often fabricated by welding. From a fatigue point of view, the structural details and especially, the welded details are the most prone to fatigue damage and failure. Design against fatigue requires information on the fatigue resistance of a structure's critical details and the stress loads that act on each detail. Even though, dynamic simulation of flexible bodies is already current method for analyzing structures, obtaining the stress history of a structural detail during dynamic simulation is a challenging task; especially when the detail has a complex geometry. In particular, analyzing the stress history of every structural detail within a single finite element model can be overwhelming since the amount of nodal degrees of freedom needed in the model may require an impractical amount of computational effort. The purpose of computer simulation is to reduce amount of prototypes and speed up the product development process. Also, to take operator influence into account, real time models, i.e. simplified and computationally efficient models are required. This in turn, requires stress computation to be efficient if it will be performed during dynamic simulation. The research looks back at the theoretical background of multibody simulation and finite element method to find suitable parts to form a new approach for efficient stress calculation. This study proposes that, the problem of stress calculation during dynamic simulation can be greatly simplified by using a combination of Floating Frame of Reference Formulation with modal superposition and a sub-modeling approach. In practice, the proposed approach can be used to efficiently generate the relevant fatigue assessment stress history for a structural detail during or after dynamic simulation. Proposed approach is demonstrated in practice using one numerical example. Even though, examples are simplified the results show that approach is applicable and can be used as proposed.

show abstract

Section: The Floating Frame Of Reference Formulationmentioning

confidence: 99%

Sub-modeling approach for obtaining structural stress histories during dynamic analysis

2013

View full text Add to dashboard Cite

show abstract

“…5. In the case of large relative rotation between the connected links, the dynamics of these chains, even for a planar rigid-link chain, is governed by highly nonlinear equations as the result of the geometric nonlinearities due to the finite relative rotations (Korkealaakso et al, 2009). For this type of joints, the FFR or rigid body formulations lead to a highly nonlinear connectivity conditions as the result of using orientation parameters.…”

Section: Structural and Nonstructural Discontinuitiesmentioning

confidence: 99%

“…The two connected bodies can 13 arbitrarily rotate with respect to each other. For a spherical joint between two finite elements i and j , the algebraic spherical joint constraint equations can be written as…”

Section: Spherical Jointmentioning

confidence: 99%

“…This formulation leads to a highly nonlinear inertia matrix that has a strong coupling between the reference and deformation coordinates. In addition to the high nonlinearity of the inertia forces, the joint constraints equations developed using the FFR formulation are also highly nonlinear because of the use of orientation parameters (Korkealaakso et al, 2009). …”

mentioning

confidence: 99%

See 1 more Smart Citation

Ideal Compliant Joints and Integration of Computer Aided Design and Analysis

Hamed¹,

Jayakumar²,

Letherwood³

et al. 2013

View full text Add to dashboard Cite

Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. REPORT DATE NOV 20132. REPORT TYPE Technical Report3 ; #24314 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) U.S. Army TARDEC, 6501 East Eleven Mile Rd, Warren, Mi, 48397-5000 SPONSOR/MONITOR'S ACRONYM(S) TARDEC SPONSOR/MONITOR'S REPORT NUMBER(S) #24314 DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT This paper discusses fundamental issues related to the integration of computer aided design and analysis (I-CAD-A) by introducing a new class of ideal compliant joints that account for the distributed inertia and elasticity. The absolute nodal coordinate formulation (ANCF) degrees of freedom are used in order to capture modes of deformation that cannot be captured using existing formulations. The ideal compliant joints developed can be formulated, for the most part, using linear algebraic equations, allowing for the elimination of the dependent variables at a preprocessing stage, thereby significantly reducing the problem dimension and array storage needed. Furthermore, the constraint equations are automatically satisfied at the position, velocity, and acceleration levels. When using the proposed approach to model large scale chain systems, differences in computational efficiency between the augmented formulation and the recursive methods are eliminated, and the CPU times resulting from the use of the two formulations become similar regardless of the complexity of the system. The elimination of the joint constraint equations and the associated dependent variables also contribute to the solution of a fundamental singularity problem encountered in the analysis of closed loop chains and mechanisms by eliminating the need to repeatedly change the chain or mechanism independent coordinates. It is shown that the concept of the knot multiplicity used in computational geometry methods, such as B-spline and NURBS (Non-Uniform Rational B-Spline), to control the degree of continuity at the breakpoints is not suited for the formulation of many ideal compliant joints. As explained in this paper, this issue is closely related to the inability of B-spline and NURBS to model structural discontinuities. Another contribution of this paper is dem...

show abstract

“…A multibody system is a structure constructed with flexible or rigid bodies that are connected by joints or force elements [6], [7]. The joints can be modeled using combinations of different basic constraints that define the allowable movement between bodies connected to these.…”

Section: Modelling Of the Mechanicsmentioning

confidence: 99%

Simulation, modeling, and virtual testing of electric-drive-powered mechatronic systems

Lindh

2013

2013 International Conference-Workshop Compatibility and Power Electronics

View full text Add to dashboard Cite

This paper discusses the problems that arise when analyzing mechatronic systems that are driven by controlled electrical drives. Both the drive and mechanics contribute to the dynamics including various sources of nonlinearities and timevarying components. The paper discusses various different means of simulating such systems, with a special reference to software-in-loop and hardware-in-loop simulations.A mechatronic system is a combination of mechanical structures, electronics, pneumatics, hydraulics, and sensor technology, also requiring program and control design. Applications from robots and manipulators to vehicles, cranes, and machine tools, to mention but a few, constitute a large variety of different mechatronic combinations. Hence, mechatronics is truly a multidisciplinary field of research and engineering.This paper discusses modeling and simulation aspects of systems that are driven by controllable electric drives or other electric actuators. The dynamic behavior of such systems depends on mechanics, the electric drive, and control.The modeling of such systems as a whole is not straightforward. However, it is important to model the whole system if we wish to capture or fix problems such as oscillation, or if we want to improve the performance of the system or achieve a higher energy efficiency. Oscillations caused by the flexible modes of mechanical structures can be determined by analytical calculations or by the FEM, at least in the case of simple mechanical structures, yet the interactions between mechanics, the electric drive, and its control are hard to solve without treating the system as a whole. The energy efficiency of electrical drives is already high, and continues to increase. However, efficiency improvements tend to be expensive and small in terms of absolute value. Often, by analyzing and optimizing the control of processes where electrical drives are used, a significant efficiency improvement (tens of %) can be achieved, often without any extra investment costs.The question is, which kinds of frequency converter, motor, and mechanics models are adequate for the simulation of such systems. I. PROPERTIES OF MECHATRONIC SYSTEMSObviously, the characteristics of a mechatronic system vary between systems. However, some typical properties can be listed. The first, already recognized, property is the interconnection between components. There are interconnections between parts of the mechanical components, mechanics, and motor drives with their control, but also between other upper controllers such as PLCs in factory applications or the Engine Control Units (ECUs) of vehicles. In addition, the systems are connected with the environment. Examples of mechatronics systems in different environments are vehicle applications in a landscape with hills and different friction conditions, materials that are handled by material handling machines, or wind turbine applications operating in varying wind conditions.Most of the systems include nonlinear behavior to such a degree that pure linear models cannot be...

show abstract

Description of joint constraints in the floating frame of reference formulation

Cited by 19 publications

References 29 publications

Sub-modeling approach for obtaining structural stress histories during dynamic analysis

Sub-modeling approach for obtaining structural stress histories during dynamic analysis

Ideal Compliant Joints and Integration of Computer Aided Design and Analysis

Simulation, modeling, and virtual testing of electric-drive-powered mechatronic systems

Contact Info

Product

Resources

About