c) Unique In other words, Fictiv lets engineers, like you, engineer. d) Uniform strain 11. 11. C. any of the metals commonly used in aircraft fasteners. a)N X N, where N is no of nodes We already know that stiffness is directly related to deflection, but we still need to derive the formula. c) The final velocity )J{jIa\ gh0"ZG*adj))uyMtB{>czeFUoi-t2Ymok.Ozo}m*P4*xz)3A+#=J@[b!ui\Nl>mTehSF%u7SKR=$ZzH]w;Rg `d@aN_74d 00G? The stiffness is a one of the key measures in. 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. b) Symmetric A highly ordered, hexagonal, nacre-like composite stiffness is investigated using experiments, simulations, and analytical models. Answer: b A. is lighter than single sheet skin of the same strength [2], The stiffness, A.B. If were looking at square or rectangular bars, the dimensions of concern are different we need to know the base, the height, and the length of the feature. 32. He has discussed his diagnosis with the urologist. are best avoided by d) Degrees of freedom, DoF a) Different matrices Explanation: Penalty approach is the second approach for handling boundary conditions. Use of linear shape functions results in a constant B matrix. Explanation: NBW means half bandwidth. 6.3 Aircraft Materials - Composite and Non-Me, 6.3 Aircraft Material - Composite and Non-met. This can be evaluated both subjectively, or objectively using a device such as the Cutometer. c) 2 nodes It depends whether the model to be solved is "Force-Controlled" or "Displacement-Controlled". b) Nodes and displacement You can see that the boss is not simply a cylinder, it includes gussets that make it a little harder to calculate the area MOI. B. low speed and high pressure drills. 7-36 AMA037 large deformations), material nonlinearity's (i.e. Then these shape functions are called ____ b) Y direction Answer: a 7-18 AMA037 V. GOPALAKRISHNAN and CHARLES F. ZUKOSKI; "Delayed flow in thermo-reversible colloidal gels"; Journal of Rheology; Society of Rheology, U.S.A.; July/August 2007; 51 (4): pp. This is called isoparametric formulation in literature. if the stress of the element is below the yield stress, the stiffness is constant and doesn't change . It is used to define nodes in the entire body. a) 0.3125 d) Program SOLVING Production quality parts without the tooling investment. Third step is to evaluate reaction force at each point. springs connected to each other in series, Multiscale Modeling in High-Frequency Electromagnetics. c) Matrix form B. occurring parallel to the direction of the beam. Answer: d 19. b) Unstable equilibrium points Linear combination of these shape functions represents a ______ r-D*kkC_*}|t~vr#~(jo/ %}JcE. a) Strain matrix Example for plane stress problem is Strip footing resting on soil mass a thin plate loaded in a plane a long cylinder a gravity dam Show Answer 3. c) Strain and displacement A. Explanation: Traction or tractive force is the force used to generate motion between body and a tangential surface, through the use of dry friction, through the use of hear force. a) Horizontal stress load a) Essential boundary condition Explanation: For a global stiffness matrix, a structural system is an assemblage of number of elements. Editors note: We published a follow-up blog post on this topic on 4/4/14. A failure in certification testing can stop your product development process dead in its tracks, resulting in large costs and significant [], Understanding the differences between the mechanical properties of strength vs. stiffness vs. hardness is foundational in mechanical engineering, yet these properties are often confused. This resistance is referred to as stiffness. Sometimes there is a metal sleeve in the bore to give it more strength. 60:40 Temperature is a variant which varies from one point to another point. These materials have three mutually perpendicular planes. Flexibility coefficients depend upon loading of the primary structure. 22. a) Identity matrix In the FEA of a fluid mechanics problem, we need to find . c) Uniparametric a) Stress and strain B. Continuum is discretized into_______ elements. What is the Global stiffness method called? Explanation: A drive shaft, driveshaft, driving shaft, propeller shaft (prop shaft), or Cardan shaft is a mechanical component for transmitting torque and rotation, usually used to connect other components of a drive train that cannot be connected directly because of distance or the need to allow for relative movement between them. When starting to model a structure, one of the critical choices that we need to make is deciding on how much detail we are really interested in. A. room temperature. Essentially, the factor of safety is how much stronger the system is than it needs to be for an intended load. At the end of the shift, 2535mL2535 \mathrm{~mL}2535mL were emptied from the drainage bag of the irrigation system. a) Infinite Which of the following is true for the stiffness matrix (K)? b) Penalty approach method Chest x-ray, bone scan, and abdominal CT scan are all negative. d) Sodium The same element is used in the COSMOS program at The Boeing Company and in the SAMIS program developed at the Jet Propulsion Laboratory. a) Force and load d) T 470 0 obj <>/Filter/FlateDecode/ID[<990D5F91FEAFC516B504CE6DFAD71573><776AC5C94209A647AED43EF87496B39F>]/Index[458 26]/Info 457 0 R/Length 73/Prev 473555/Root 459 0 R/Size 484/Type/XRef/W[1 2 1]>>stream Answer: d The external loads and the internal member forces must be in equilibrium at the nodal points. Which is not a step to ensure proper bonding of a composite Stiffness matrix depends on 1.Material, 2.Geometry, 3.Both, 4.None b) Programming functions Engines). c) 25-75 7-44 AMA004 Explanation: The given cantilever beam is subjected to a shear force at the free end, thus tx(0, y)=0 and ty(0, y)=-hT. 7-38 AMA078 a) Degrees of freedom b) Number of nodes State whether the above statement is true or false a) true b) false View Answer 2. Answer: a Pro-tip: Check out Part Two of this series, How to Design for Stiffness Using Material Properties. c) Rows and columns (The element stiffness relation is important because it can be used as a building block for more complex systems. d) Loads 7-20 AMA037 A potted compound repair on honeycomb can usually be 40:60 A. The principle advantage to curing composite parts with an a) Stable equilibrium points 28. Traction force term represented as ___ Explanation: Stiffness is amount of force required to cause the unit displacement same concept is applied for stiffness matrix. geometry/distribution, and properties of the con-stituent phases, it is possible to design materials with property combinations that are better than those found in the metal alloys, ceramics, and polymeric materials. Answer: c 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. The stiffness matrix is an inherent property of the structure. The stiffness matrix is an inherent property of a structure. c) Displacement vector Explanation of the above function code for global stiffness matrix: -. For a body with multiple DOF, to calculate a particular direct-related stiffness (the diagonal terms), the corresponding DOF is left free while the remaining should be constrained. What is the material layer used within the vacuum bag =0.3125. What is the Strain energy equation? c) Polynomial (A) bar (B) triangle (C) hexahedron (D) tetrahedron Answer B QUESTION No - 17 Explanation: Multiple constraints is one of the method for boundary conditions it is generally used in problems for modeling inclined rollers or rigid connections. c) Shaft and sleeve Answer: a a) 2 degrees of freedom Displacement is the difference between the final and initial position of a point. 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. Answer: d The unknown displacement field was interpolated by linear shape functions within each element. b) 90-180 Explanation: A sleeve is a tube of material that is put into a cylindrical bore, for example to reduce the diameter of the bore or to line it with a different material. Using the Euler-Bernoulli beam theory, the following matrix equation can be formed:. Well put all the important information into our deflection calculator, as shown below: Our calculator predicts that the beam will deflect 0.144 at the end, which sounds like a pretty reasonable number. Where [B] is the strain-displacement matrix obtained from the . Explanation: The shape functions are physically represented by area co-ordinates. c) Y direction a) Minimum stresses 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. Beams are used in two and three dimensions to model slender, rod-like structures that provide axial strength and bending stiffness. In industry, the term influence coefficient is sometimes used to refer to the coupling stiffness. Answer: d 38. C. impacts to the surface by debris. If a circular pipe under internal or external pressure, by symmetry all the points move radially. b) Point loads only B. d) Singular matrix After consulting with his urologist, A.B. c) Thermal strain However, the derivation is entirely different from that given in Ref. a) Laminate {\displaystyle k,} There are other methods for determining part stiffness, area MOI, and deflection an FEA study is the first that comes to mind. So by this element stiffness matrix method we can get relation of members in an object in one matrix. Lower order polynomials are chosen as shape functions. c) Elements How can I put the real number of stiffness constant to a membrane? In finite strain stiffness optimization, several potential definitions of the structural stiffness are available, such as structural strain energy, end displacement, end compliance, and end stiffness (Kemmler et al. For example, a point on a horizontal beam can undergo both a vertical displacement and a rotation relative to its undeformed axis. The performance of finite element computation depends strongly on the quality of the geometric mesh and . Answer: b point of the heat source. B. fine tooth saw carbide saw blade. a) Co-efficient of thermal expansion In a Belleville spring, load-deflection characteristics and stress distribution can be obtained by dividing the area into ____ Explanation: Global load vector is assembly of all local load vectors. Read Part 2 to learn how to compute the stiffness of linear elastic structures in 2D and 3D. Answer: b c) Area co-ordinates 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? 1. Which is not a characteristic of acrylic plastics Unidirectional composites are stacked at different fiber orientations to form a ______ 5. b) Displacement functions The Force required to produce unit displacement is Pressure Traction Stiffness None Show Answer If the structure is divided into discrete areas or volumes then it is called an _______ For example, lets look at a boss with gussets (below) similar to what I described in a previous article. Answer: c a) =D 7-15 AMA037 If N3is dependent shape function, It is represented as ____ b) yx0 In the XYZ Cartesian system, all the strain components except yzand zxare non-zero. For an elastic body with a single degree of freedom (DOF) (for example, stretching or compression of a rod), the stiffness is defined as. c) Uniform The elasticity tensor is a generalization that describes all possible stretch and shear parameters. On gathering stiffness and loads, the system of equations is given by. I the distribution of the change in temperature T, the strain due to this change is ____ Corner of each element is called a node. 7-40 AMA078 A features shape and size impact the formulas required for a calculation of stiffness, so lets consider those geometric properties first. Explanation: The displacement components of a local node is represented in x and y directions, respectively. Explanation: A banded matrix is a sparse matrix whose non zero entities are confined to a diagonal band, comprising the main diagonal and zero or more diagonals on either side. Proper prepreg composite lay-up curing is generally 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 PDFs for offline use. We take free online Practice/Mock test for exam preparation. Each MCQ is open for further discussion on discussion page. All the services offered by McqMate are free. The global stiffness matrix is constructed by assembling individual element stiffness matrices. b) 3 degrees of freedom d) Equal A Belleville washer is a type of spring shaped like a washer. A node is a co-ordinate location in space where degrees of freedom are defined. 32. c) Force It is found by forcing the displacement and rotation of the left end to be zero. 3. Stiffness matrix represents a system of ________ If Q1=a1then a1is _________ a) Column height The gussets are added to increase the part stiffness and strength, but how do we calculate this without extensive hand calculations? c) Load C. in a refrigerated environment under 0 degrees F. 7-26 AMA037 c) 22 a) 6 In one dimensional problem, each node has _________ degrees of freedom. Explanation: For plane elasticity problems, the boundary conditions are one of the governing equations. . 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. Loads, the factor of safety is how much stronger the system of equations is given by the bore give... Which of the element is below the yield stress, the following equation... Node is represented in x and y directions, respectively a follow-up blog post on this on. 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