c) KKe This approach is easy to implement in a computer program and retains it simplicity even when considering general boundary conditions. d) Cg solving Explanation: Once the shape functions are defined, the linear displacement field within in the element can be written in terms of nodal displacements q1and q2and matrix notation as q=[q1,q2]. Answer: b throughout their Academic career. A. eliminates the need for vacuum bagging. b) Quadratical The full stiffness matrix Ais the sum of the element stiffness matrices. For other uses, see, Pages displaying wikidata descriptions as a fallback, Pages displaying short descriptions of redirect targets. In COMSOL Multiphysics, you can set up the 1D model by first choosing a 2D or 3D space dimension and then using either the Truss or the Beam interface. Explanation: Poissons ratio is the ratio of transverse contraction strain to longitudinal extension strain in the direction of stretching force. Investigating this scenario would also mean that we would have to introduce additional stiffness terms that would correlate the bending force with the out-of-plane displacements. Lets look at our calculator again to run some quick calculations to compare a round tube and a solid round bar. c) Perpendicular A solid beam of length L, width b, and thickness t, with its sides oriented along the x-, y-, and z-directions of a Cartesian coordinate system. Write the element stiffness for a truss element. Explanation: Global coordinate system corresponds to the entire body. B. low speed and high pressure drills. Answer: a 2 are true. If no scratches are visible after transparent plastic enclosure A. may be softened by heat. [1], The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. One dimensional element is the linear segments which are used to model ________ c) f=[fx,fy]T Explanation: Galerkin method provides powerful numerical solution to differential equations and modal analysis. a) Zero Stiffness Matrix to solve internal forces in 1D (Part 1 of 2) - Finite Element Methods Blake Tabian 34K views 6 years ago Derivation of stiffness matrix of 1D element Nivrutti Patil 7.3K. The ratios between the reaction forces (or moments) and the produced deflection are the coupling stiffnesses. Such cases will be discussed in a future blog post. Chapter: Civil : Structural Analysis : Stiffness Matrix Method Element and global stiffness matrices - Analysis of continuous beams - Co-ordinate transformations - Rotation matrix - Transformations of stiffness matrices, load vectors and displacements vectors - Analysis of pin-jointed plane frames and rigid frames( with redundancy vertical to two) 18. Hopefully, this conveys the message that seemingly small increases in part diameter or height will greatly increase the part stiffness. Answer: a c) Elements a) Programming equations 150 degrees d) yz0 7-23 AMA037 40. c) Material https://quizack.com/mechanical-engineering/finite-element-method/mcq/stiffness-matrix-depends-on, Note: This Question is unanswered, help us to find answer for this one, More Mechanical Engineering MCQ Questions, The force required to produce unit displacement is, The distributed force per unit area on the surface of the body is, Domain is divided into some segments called, Unit of body force acting on every elemental volume of the body is, ________ are used to find the nodal displacements in all parts of element. b) Symmetric and square elasto-plastic material), and contact. a) Nodes and elements d) uTTl Explanation: Minimum potential energy theorem states that Of all possible displacements that satisfy the boundary conditions of a structural system, those corresponding to equilibrium configurations make the total potential energy assume a minimum value. !DI&RB/ b) A-A1 Answer: a Using a simplistic definition where stress is equal to force per unit cross-section area, \sigma=F/A, where A=bt, and strain is equal to the ratio of deformation to the original length, \epsilon=u/L, and combining these, we get F=(EA/L)u. One source of truth for team spend by project. Answer: b The best way to understand which moment of inertia to consider is to think about applying a load around which axis will the bar rotate or wrap? [4] The pliability of skin is a parameter of interest that represents its firmness and extensibility, encompassing characteristics such as elasticity, stiffness, and adherence. Explanation: Mohrs circle is two dimensional graphical representation of the transformation law. d) Constant Give an example of orthotropic material? Thus, xx0, yy0, zz0, xy0, where as yz=0 and zx=0. This gives us the equivalent single-spring stiffness of the 1D beam as: This indicates that for the given modeling parameters, the solution (k = 4109 N/m) of the 1D model tends to be that of the 0D model when evaluated at x = L. An additional advantage of moving over to a 1D model is that we can now explore the effect of loading direction. 1 and No. 28. [k] is the structure stiffness matrix that relates the two vectors. 24. Explanation: Stiffness matrix represents the system of linear equations that must be solved in order to ascertain an approximate solution to the differential equation. The vector form of equations of motion is D*+f=u, where f denotes body force vector, is the stress vector, u is the displacement vector, D is a matrix of differential operator and is the density. As node 22 is located at the center, it is neither pushed nor pulled; thus, the effective force at node 22 is always zero. The stiffness and force modifications are made to account for the boundary conditions. d) Crystals Material Geometry both material and geometry none of the above Answer: both material and geometry For 1-D bar elements if the structure is having 3 nodes then the 13. stiffness matrix formed is having an order of 2*2 3*3 4*4 6*6 Answer: 3*3 When thin plate is subjected to loading in its own plane only, d) Local displacement vector Answer: c b) yx=0 Answer: d B. create sonogram pictures of the areas being inspected. d) Vector method In penalty approach, rigid support is considered as a spring having stiffness. In stiffness matrix, all the _____ elements are positive. Elastic modulus is a property of the constituent material; stiffness is a property of a structure or component of a structure, and hence it is dependent upon various physical dimensions that describe that component. Here C is a large number. Explanation: Generally global stiffness matrix is used to complex systems. c) 20. Stresses due to rigid body motion are _______________ patch to an aluminum surface d) Identically Im going to focus on relatively simple shapes for the main examples, and will touch on complex shapes towards the end. curing process. Explanation: By penalty approach we can derive boundary conditions of an element or a structure. Crack your Job Placement Aptitude with LMT Aptitude Series at Just 799 Only | Click Here, Your Branch 168 Welsh Street San Francisco, CA 94107, 1001 N. Central, Suite 802 Phoenix, AZ 85004, 5-6 Building 11, Changhua Creative Park, Panyu District, Guangzhou, 511495, Pride House Office No.402, 4th Floor, Ganeshkhind Road, Pune 411016. Axisymmetry implies that points lying on the z- axis remains _____ fixed. If there are nonlinearities, then it is important to use the correct linearization point. However, it also translates to the idea that each of these springs has its own stiffness. Explanation: A body force is a force that acts throughout the volume of the body. degrees of freedom a d) [NBW X NBW] Answer: b d) Co-ordinate Answer: d Deformation proportional to the stress applied within the elastic limits of the material. c) zx0 Before we dive in, we need to define stiffness mathematically. a) Computer functions C. prevents expansion of the structure during the Even the simplest designs can be sensitive to part stiffness. matrix becomes non-symmetric is when the stiffness characteristic is highly. core material with thermoplastic resin. 17. c) Natural Explanation: A Belleville washer, also known as a coned-disc spring, [1] conical spring washer, [2] disc spring, Belleville spring or cupped spring washer, is a conical shell which can be loaded along its axis either statically or dynamically. c) Principal axes lightning dissipation. The pistons run directly in the bores without using cast iron sleeves. c) Polynomial hi 23. A. assembled with certain aluminum alloys. It is denoted by symbol . 7-40 AMA078 c) Displacement vector c) Nodes and elements Answer: c For example, in Design Example 16.1, we discuss how a tubular shaft is designed that meets specified stiffness requirements. This is called isoparametric formulation in literature. They show you these matrices, they attach some physical meaning, and in my opinion this leads you to developing a dubious physical intuition for the field. A. core in composite construction is, flame resistant. If an aircraft's transparent plastic enclosures exhibit fine b) Equation Unidirectional fiber- reinforced composites also exhibit _______ behavior. a) Spherical The information of array of size and number of elements and nodes per element can be seen in ___ Better estimates of maximum stress may be obtained even with coarser meshes. For large-strain elements in a large-strain analysis (NLGEOM,ON), the stress stiffening contribution is computed using the actual strain-displacement relationship (Equation 3-6).One further case requires some explanation: axisymmetric structures with nonaxisymmetric deformations. Discretization includes both node and element numbering, in this model every element connects two nodes. b) [NBW X N] 28. a) Shape functions, N 30. Explanation: The given cantilever beam is subjected to a shear force at the free end. d) 0.3 c) Load values c) x=d/du Explanation: =Bq a) xy=0 b) Material property matrix, D Hi, thank you for writing this blog. What is the magnitude of the force at node 22 if the moment M is replaced by an equivalent distributed force at x=acm? For plane elasticity problems in three dimensions, which option is not responsible for making the solutions independent of one of the dimensions? a) x-, y- co-ordinates d) Mohrs circle method While part stiffness can be modified with geometry, material stiffness is a property of the material itself. He is planning to have surgery in 2 weeks but is concerned about the possible consequences of surgery. Further measures of stiffness are derived on a similar basis, including: The elastic modulus of a material is not the same as the stiffness of a component made from that material. a) T Answer: a A. The Supplementary Material for this article can be found . Read Part 2 to learn how to compute the stiffness of linear elastic structures in 2D and 3D. b) Load b) Linearly The stiffness should be considered as a combination of both material and structural properties, which form a mechanical response to a given load. B. Production-grade steel tooling, as fast as 2 weeks. To do so, we should try to answer the following questions and possibly several others depending on what the modeling objective is: We will start by looking at a 0D model of the beam where all effects related to loading, deformation, and material response are lumped into a single point in space and the entire beam is modeled as a single spring. By signing up, you agree to our Terms of Use and Privacy Policy. b) q=[q1,q2]T Each node has only _______ In COMSOL Multiphysics, you can model the 0D case using the Global ODEs and DAEs interface (for time-dependent simulations) or by simply setting up Parameters or Variables in a 0D space dimension model. Explanation: Nodes will have nodal displacements or degrees of freedom which may include translations, rotations and for special applications, higher order derivatives of displacements. 9. How can I put the real number of stiffness constant to a membrane? Nonlinear analysis. In shape functions, _________ must be continuous across the element boundary. C. toothless diamond coated saw blade. a) Dimensions being inspected. The geometric deformation increases with the square of the rotation of the element. An example of this is provided later.) 37. For time-dependent problems in FEA, which variables must be specified for each component of the displacement field problems? It is found by forcing the displacement and rotation of the left end to be zero. Answer: a 2 and 3 Stiffness matrix method is used for structures such as simply supported, fixed beams and portal frames. 7-16 AMA037 Explanation: Stiffness matrix is a inherent property of the structure. For modeling of inclined roller or rigid connections, the method used is ___ Answer: b This method is used to derive boundary conditions. We can write the stress-strain relations for a linear elastic material exploiting these symmetries as follows: 2 6 6 6 6 6 6 4 11 22 33 23 13 12 3 7 7 7 7 7 7 5 = 2 6 6 6 6 6 6 . a) Multiple matrix Assuming that the Youngs modulus and cross-section area do not vary along the length of the beam, if we discretize the beam into n-number of springs in series, in our case, the stiffness of each spring (ki) will be k_i=nEA/L. 13. A zero rank tensor is a scalar, a first rank tensor is a vector; a one-dimensional array of numbers. The extent of separation damage in composite a) Non symmetric and square d) Lagrange shape functions no_nodes = size (node_xy,1); - to calculate the size of the nodes or number of the nodes. Explanation: In computation of Finite element analysis problem defined under initial or boundary conditions. d) Four What is the use of homogeneous coordinates and matrix representation? The stiffness, in general, can be a function of material properties, material orientation, geometric dimensions, loading directions, type of constraint, and choice of spatial region, where loads and constraints are applied. Explanation: The equations of motion for plane elasticity problems are given by D*+f=u in the vector form, where f denotes body force vector, is the stress vector, u is displacement vector, D is a matrix of the differential operator, and is the density. Copyright 2023 Fictiv. C, the element stiffness equations are 1 11 1 12 2 13 3 14 4 15 5 16 6 f1 In the design of wheeled or tracked vehicles, high traction between wheel and ground should be more desirable. a) Global displacement vector {Fkx} = [ ]{ } (1) In this study, the Hexapod stiffness model relies on truss elements. c) Area co-ordinates At the end of the shift, 2535mL2535 \mathrm{~mL}2535mL were emptied from the drainage bag of the irrigation system. Explanation: By elimination approach method we can construct a global stiffness matrix by load and force acting on the structure or an element. For questions related to your modeling, please contact our support team. 34. 19. b) One matrix Accelerating new product introduction for the robotics industry, Accelerating new product introduction for the consumer products industry, Accelerating new product introduction for the medical industry, Accelerating new product introduction for the automotive industry, Accelerating new product introduction for the aerospace industry. 7-14 AMA037 15. b) Large deformations in linear elastic solids The Constant strain triangle can give____ stresses on elements. A. cure the film adhesive material at 250 degrees F. c) Matrix c) Building technique A. are made from the same composite material to If a finite element mesh has eight nodes and two degrees of freedom at each node, then the total DOF equals two times eight, i.e., sixteen. Explanation: Shape functions are interpolation functions. c) Vector displacements 26. c) Both Precision and accuracy d) On element No hanger designs come close to the materials yield strength, but their function depends on the stiffness of the design. Discretization can be done. high strength and high elastic modulus for its weight.) 25. A rich library of design guides and manufacturing tips. In the two dimensional elements the x-, y-, co-ordinates are mapped onto -,, co-ordinates. C. install anchor tabs on the aluminum surface. The structure stiffness matrix [S] is obtained by assembling the stiffness matrices for the individual elements of the structure. b) dV=dA One dimensional element is the linesegment which is used to model bars and trusses. Body force is distributed force acting on every elemental volume. a) High traction force d) Matrix The diagonal terms in the matrix are the direct-related stiffnesses (or simply stiffnesses) along the same degree of freedom and the off-diagonal terms are the coupling stiffnesses between two different degrees of freedom (either at the same or different points) or the same degree of freedom at two different points. The finite element method is used to solve the problem ______ Explanation: For an orthotropic material, E1and E2are the principal (Youngs) moduli in the x and y directions, respectively. With temperature effect which will vary linearly? We will explore these cases here. 8. c) Force Explore opportunities to join the Fictiv team. A node may be limited in calculated motions for a variety of reasons. d) Kinematic energy point of the heat source. Fitting Hyperelastic Material Parameters from Test Data 3.9.Summary 3.10.Exercises The 1D structure will be modeled as an Euler-Bernoulli beam. a) Nodes b) Iterative equations a) =D(-0) d) Load 30. Answer: c It is noted that for a body with multiple DOF, the equation above generally does not apply since the applied force generates not only the deflection along its direction (or degree of freedom) but also those along with other directions. c) Both element force vectors and point loads The devel- opment of the stiffness matrix proceeds in a straightfor- Answer: d 7-33 AMA037 In dividing the elements a good practice may be to choose corner angles in the range of ____ a) Load vector 19. Understanding the definition of stiffness Knowledge of the mechanical properties of materials. Specifically, it measures the fractional change in size per degree change in temperature at constant pressure. b) Penalty approach method C. dirt and foreign substances from between c) Thermal expansion Only No. A. Now, lets run the calculations for part stiffness and deflection. Editors note: We published a follow-up blog post on this topic on 4/4/14. d) Element equation d) Shape function A simulation geometry is made by digital microscope measurements of the specimens, and a simulation is conducted using material data based . If N3is dependent shape function, It is represented as ____ d) yy=0 a) A1/A d) Thermal stress b) Load b) 0.05 The stiffness matrix is an inherent property of the structure. Use of quadratic interpolation leads to more accurate results. c) Uniform Penalty approach method is easy to implement in a ______ b) Infinity W;>5/)b36dsC 0=Lq'wulXccCnp|_%3MF@X2qiU8Dscckxm=^e2` b) Energy matrix Explanation: Strain energy is defined as the energy stored in the body due to deformation. e[XX"J iE(+QRlz9{n9 @ tt QA#f9F vL{kz%C*O:lMMb\fZ0/2n'nHnc =t&k)c L>GA%W_tq So your stiffness matrix will be 8x8. . Learn about our company, leadership, and mission to transform the manufacturing industry. 16. A. high speed, low pressure drills. Answer: a Explanation: The size of the assembled stiffness matrix is equal to the total DOF of a structure. b) Nodes In particular, for basis functions that are only supported locally, the stiffness matrix is sparse. Stiffness matrix represents a system of ________ d) No traction force d) Distance and displacement We already know that stiffness is directly related to deflection, but we still need to derive the formula. plastic cools. b) Element-strain displacement matrix a) N3= For time-dependent problems, the initial displacement and velocity must be specified for each component of the displacement field. Then reduced stiffness matrix can be obtained by eliminating no of rows and columns of a global stiffness matrix of an element. Answer: d The material's tensile modulus The material's price per pound The strengthening ability of the material. Answer: b a) Force and load Designing products for load bearing applications is a complex and multifaceted task, so its important for a designer to have a toolbox of techniques that improve design quality. c) Only elemental {\displaystyle M\times M} 21qb)wYynW[uczqWU,BW{ur}EOa^xePIfxkK`YkN[U\HSA!3rE fasteners and metal structure fasteners is that For constant strain elements the shape functions are ____ What is the Strain energy equation? He has a history of hypertension and atrial fibrillation, for which he receives warfarin (Coumadin), metoprolol (Toprol), digoxin, and lisinopril/hydrochlorothiazide (Zestoretic). We can figure that out using the following mathematical approach. d) Undefined A snapshot of the boundary conditions used in the Beam interface. Engines). wet lay-ups is generally considered the best for strength? 44. McqMate.com is an educational platform, Which is developed BY STUDENTS, FOR STUDENTS, The only Explanation: The strain field associated with the given stress field has the form =S, where the matrix S is a symmetric matrix, and it is called elastic compliances matrix. d) Both interpolation and displacement function c) Approximately A. a) No. Where the members are organized so that the assemblage as a whole behaves as a single object. Explanation: A degrees of freedom may be defined as, the number of parameters of system that may vary independently. a) xy=0 Stress is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other. Answer: c c) Axes a) Different matrices The overall concept of leveraging geometric relationships to increase stiffness in this manner is pretty simple, but the formulas can appear daunting. Answer: d c) Co-ordinates 7-41 AMA078 b) Notches and fillets In this case, a 0D model is also a single degree of freedom (SDOF) representation of the beam. In elimination approach method, extract the displacement vector q from the Q vector. d) Equal d) 2 12. Better approximations are obtained by increasing the number of elements. be installed hot and tightened to a firm fit before the Check out Fictivs CNC Machining Capabilities, then create an account and upload your part to see what our instant quote process, design for manufacturability feedback, and intelligent platform can do for you. N1, N2, N3 are not linearly independent only one of two of these are independent. Press fit on elastic shaft, may define pairs of nodes on the contacting boundary, each pair consisting of one node on the _____ and one on the ______ tapping method, a dull thud may indicate 7-27 AMA045 The stiffness matrix depends on the nature of the elements in the structure, whether they are truss or frame elements, their geometric orientation and connectivity. Explanation: The finite element method is a numerical method for solving problems of engineering and mathematical physics. d) Reaction force Proper prepreg composite lay-up curing is generally Answer: d d) Thermal effect The points where triangular elements meet are called ____ Which is the correct option for the following equation? Stiffness matrices are square and symmetric. a) Potential energy a) Interpolation function Answer: a In stiffness matrix, all the _____ elements are positive. Answer: c d) No. What is meant by stiffness matrix? FEM basis is in the stiffness matrix method for structural analysis where each element has a stiffness associated with it. For a circular pipe under internal or external pressure, by symmetry all points move _____ ). Explanation: The displacement components of a local node is represented in x and y directions, respectively. Copyright 2023 McqMate. Answer: a A category of plastic material that is capable of softening or View Answer 3. Explanation: In finite element method elements are grouped as one dimensional, two dimensional and three dimensional elements. Answer: b d) Specified displacement In Imperial units, stiffness is typically measured in pounds (lbs) per inch. You can assign beam sections only to wire regions. 4. 1 inch in diameter. det(Ko + K.) = 0 (20) Geumetric Sti ffncss ]\'Iatrix The del"ivation ofstiffness matrices for finite elements often is based on 1111 approximate displllccment field of . 31. In the FEA of a fluid mechanics problem, we need to find . Finite element method uses the concept of _____ A. occurring perpendicular to the direction of the beam. It is based on the relative motion of the object. Answer: a Stiffness matrix depends on View all MCQs in: CAD-CAM and Automation Discussion Login to Comment Related Multiple Choice Questions For 1-D bar elements if the structure is having 3 nodes then the stiffness matrix formed is having an order of The determinant of an element stiffness matrix is always b) On surface d) Sodium The given expressions show the relationship between stress, strain and displacement of a body. 23. That is to say, the deflection of the smaller diameter tube is 170% greater than our larger diameter tube. The best cutting tool to use on composite honeycomb If Q1=a1then a1is _________ When the applied force is released, the system returns to its original shape. xz=yz=zz=0, xx(x,y), xy=xy(x,y) and yy=yy(x,y). The skin maintains its structure due to its intrinsic tension, contributed to by collagen, an extracellular protein that accounts for approximately 75% of its dry weight. The first step of penalty approach is, adding a number C to the diagonal elements of the stiffness matrix. a) Uniform All rights reserved. That is, all the elements outside the band are zero. b) Nodes and displacement d) Along the pipe 39. Second step is to extract element displacement vector. 25. So, we know which dimensions are important, and we know that shape and size impact stiffness, but how big of an impact does it actually have? Now that we know the formulas, lets put them to use with our Area Moment of Inertia Calculator to provide a method for how to calculate stiffness and deflection. 33. b) Shape 1. Explanation: Strain is defined as a geometrical measure of deformation representing the relative displacement between particles in a material body. b) 3 nodes Answer: a This is useful if we need to save weight and/or material. , Explanation: Any linear combination of these shape functions also represents a plane surface. For pain and/or loss of range of motion of a joint, see, "Flexibility" redirects here. d) Program SOLVING a) Bars and trusses The shape function is a function which interpolates the solution between the discrete values obtained at the mesh nodes. B. squeezes resin more deeply into the structure. Natural or intrinsic coordinate system is used to define ___________ 6. Answer: a hTKSaqk&xEnM oQ~ 21. Answer: a A. covered with a thin coat of wax. This correlates pretty closely between the two different approaches, so were happy with the result. c) Potential energy Last edited on 25 February 2023, at 17:23, "Collagen-Based Biomaterials for Wound Healing", https://en.wikipedia.org/w/index.php?title=Stiffness&oldid=1141556857, torsional stiffness - the ratio of applied, This page was last edited on 25 February 2023, at 17:23. b) False Answer: c 3. The size of global stiffness matrix will be equal to the total degrees of freedom of the structure. a) Longitudinal axis. d) Stress displacements Answer: c Coarser meshes are recommended for _____ In biology, the stiffness of the extracellular matrix is important for guiding the migration of cells in a phenomenon called durotaxis. where is the rigidity modulus of the material,; is the torsion constant for the section. The objective of fiber-reinforced composites it to obtain a material with high specific strength and high specific modulus. In the SAE system, rotational stiffness is typically measured in inch-pounds per degree. Explanation: Concerning the specification of the displacements (the primary degrees of freedom) and forces (the secondary degrees of freedom) in a finite element mesh, in general, only one of the quantities of each of the pairs (ux, tx) and (uy, ty) is known at a nodal point in the mesh. 31. Explanation: Element stiffness matrix method is that make use of the members of stiffness relations for computing member forces and displacement in structures. C. may be formed into shape at room temperatures. The various members such as pulleys and gears are mounted on it. Answer: c Materials have a long shelf life. Answer: c included tip angle of is recommended. Explanation: The two dimensional region is divided into straight sided triangles, which shows as typical triangulation.

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