The Behavior of Structures Composed of Composite Materials Part 13 ppsx

1972 Development of anUnderstanding of the Fatigue Phenomenon of Bonded and Bolted Joints in Advanced Filamentary composite Materials, Analysis Materials, AFFDL-TR 72-64 AD 750 132, Vol

other factors Even then practical considerations such as hole tolerances, and bolt torqueactually applied would limit the usefulness of the results for design

Therefore from a design standpoint it appears that the best approach to use is that

of Van Siclen [33], wherein simple easy to use equations can be used, which necessitatethat certain tests be performed

For any given structural component, hopefully the material system, and thelaminate orientation and number are decided on due to overall loading and environmentfor the component, rather than letting the joints control such decisions Thus, materialsystem, laminate orientation and thickness are predetermined before joint decisions aremade or considered

For that chosen laminate, tests described by Van Siclen should be performed todetermine the net tensile strength, the shear-out strength, and the bearingstrength for that particular laminate In Van Siclen’s [33] excellent paper, he presentedthe results of tests he performed on a graphite epoxy laminate Theresulting curves are given in Figures 8.12, 8.13, and 8.14

These results then are easily used with Equation (8.40) through (8.42) to design,analyze, and optimize any joint If the structural component is to be subjected tohygrothermal loads, then these tests should be carried out under those conditions, becauseKim and Whitney [34] have shown the deleterious effects of a hygrothermalenvironment If there is a normal pressure due to bolt torquing then the tests should beperformed with the intended torques applied because Stockdale and Matthews [35] haveshown that such pressure can increase bearing strength by 40% to 100% Also, the actualbolts considered should be used in these tests because Van Siclen [33] points out thedifferences in strength when countersunk fasteners or protruded head hasteners are used.With those strengths available one can then select a fastener size to transmit therequired load It should be noted that it is generally agreed upon that and

= 2 appear to be an optimum value in many cases However, using the Van Siclenequations one can, to a certain extent, optimize the mechanically fastened joint

If the laminate is too thin to transmit the required load then local stiffening isrequired Alternative methods for stiffening have been discussed by Lehman and Hawley[9] and Oplinger and Gandhi [36] and additional testing could be required in the case ofthe stiffened configuration

If the structure is subjected to fatigue loading it appears that a full cycle set oftests are required, although the preliminary design could be based upon a design forwhich there is no yielding in tension, shear-out, or bearing at the mean fatigue load

As a data bank on the three strengths is built up for various material systems andply orientations the amount of testing can be reduced

Since stacking sequence does have a significant effect on joint strength, if thestacking sequence for a structural component could be modified then the optimum designmay require a compromise between the stacking sequences best for the componentprimary purpose, and what is best for the joint strength

Thus, the design of mechanically fastened joints is rather straightforward, and theoptimization of joined structural components sufficiently complex that it is a challenge

In any case, simple analyses can be used, but some testing is required

It should also be remembered that Lehman and Hawley [9] found the addition ofadhesive bonding to a bolted joint gave strengths that are greater than similar joints usingeither bonding or bolting only Hence, in a design this also can be investigated using theVan Siclen approach discussed above

8.4 Recommended Reading

Other recommended reading for adhesive bonded joints includes that of Chamisand Murthy [37], Fujita et al [38], Tong [39], Running, Legon and Miskioglu [40],Mennetyen and Chamis [41], Liu, Raju and Yon [42], Lin and Jen [43], Pierron, Cerisierand Grediac [44], Turaga and Sun [45] and Zeng and Sun [46]

Kuno, James K (1979) Structural Adhesives Continue to Gain Foothold in Aerospace

and Industrial Use, Structural Adhesives and Bonding Proceedings of the Structural Adhesives Bonding Conference, arranged by Technology Conferences

Associates, El Segundo, California

Szepe, F (1966) Strength of Adhesive-Bonded Lap Joints with Respect to

Temperature and Fatigue, Experimental Mechanics, Vol 6, pp 280-286.

Volkersen, O (1944) Die Niet Kraft vertelung in Zug bean Spruchten Niet verb bind

ungen mit Konstaanten Lasch enguerschnitten, Luftfahrt forschungen, Vol 15, pp.

41-47

De Bruyne, N.A (1944) The Strength of Glued Joints, Aircraft Engineering, vol 16,

pp 115-118

Wang, D.Y (1963) The Effect of Stress Distribution on the Fatigue Behavior of

Adhesive Bonded Joints, ASD-TDR-63-93, AFML, July.

Kutscha, D (1964) Mechanics of Adhesive-Bonded Lap-Type Joints: Survey and

Review, AFML-TDR-64-298, December.

Kutscha, D and Hofer, K.E., Jr (1969) Feasibility of Joining Advanced Composite

Flight Vehicles, AFML-TR-68-391, January.

Lehman, G.M and Hawley, A.V (1969) Investigation of Joints in Advanced Fibrous

Composites for Aircraft Structures, AFFDL-TR-69-43, Vol 1, June.

Dickson, J.N., Hsu, T.M and McKinney, J.M (1972) Development of anUnderstanding of the Fatigue Phenomenon of Bonded and Bolted Joints in

Advanced Filamentary composite Materials, Analysis Materials, AFFDL-TR

72-64 (AD 750 132), Vol 1, June.

Grimes, G.C., et al (1972) The Development of Nonlinear Analysis Methods for

Bonded Joints in Advanced Filamentary Composite Structures, AFFDL-TR-72-97 (AD 905 201), September.

Ramberg, W and Osgood, W.R (1943) Description of Stress-Strain Curves by Three

Parameters, NACA TN 902, July.

Hart-Smith, L.J (1970) The Strength of Adhesive Bonded Single Lap Joints, Douglas Aircraft Company IRAD Technical Report MDC-J0472, April.

Hart-Smith, L.J (1973) Adhesive-Bonded Single Lap Joints, NASA-CR-112236,

January

Renton, W.J and Vinson, J.R (1973) The Analysis and Design of Composite

Material Bonded Joints Under Static and Fatigue Loadings, AFOSR TR 73-1627,

August

Renton, W.J and Vinson, J.R (1974) Fatigue Response of Anisotropic Adherend

Bonded Joints, AMMRC MA-74-8, September.

Renton, W.J and Vinson, J.R (1974) The Analysis and Design of Anisotropic

Bonded Joints, Report No 2, AFOSR TR-75-0125, August.

Renton, W.J and Vinson, J.R (1975) On the Behavior of Bonded Joints in

Composite Materials Structures, Journal of Engineering Fracture Mechanics,

Vol 7, pp 41-60

Renton, W.J and Vinson, J.R (1975) Fatigue Behavior of Bonded Joints in

Composite Materials Structures, AIAA Journal of Aircraft, Vol 12, No 5, May,

pp 442-447

Renton, W.J and Vinson, J.R (1975) The Efficient Design of Adhesive Bonded

Joints, Journal of Adhesion, Vol 7, pp 175-193.

Renton, W.J., Pajerowski, J and Vinson, J.R (1975) On Improvement in Structural

Efficiency of Single Lap Bonded Joints, Proceedings of the Fourth Army Materials Technology Conference – Advances in Joining Technology, September.

Renton, W.J and Vinson, J.R (1977) Analysis of Adhesively Bonded Joints Between

Panels of Composite Materials, Journal of Applied Mechanics, April, pp

101-106

Renton, W.J., Flaggs, D.L and Vinson, J.R (1978) the Analysis and Design of

Composite Materials Bonded Joints, Report No III, AFOSR –TR-78-1512.

Sharpe, W.N., Jr and Muha, T.J., Jr (1978) Comparison of Theoretical Experimental

Shear Stress in the Adhesive Layer of a Lap Joint Model, AMMRC MS 74-8.

Wetherhold , R.C and Vinson, J.R (1978) An Analytical Model for Bonded Joint

Analysis in Composite Structures Including Hygrothermal Effects, AFOSR TR 1337.

78-Vinson, J.R (1989) Adhesive Bonding of Polymer Composites, Polymer Engineering and Science, Mid-October, Vol 29, No 19, pp 1325-1332.

Flaggs, D.L and Crossman, F.W (1979) Viscoelastic Response of a Bonded Joint

Due to Hygrothermal Exposure, Modern Developments in Composite Materials and Structures, ASME.

Sen, J.K (1977) Stress Analysis of Double Lap Joints Bonded with a Viscoelastic

Adhesive, Ph.D Dissertation, Southern Methodist University, May.

Hart-Smith, L.J (1980) Further Development in the Design and Analysis of Adhesive

Bonded Structural Joints, Douglas Paper 6922 presented at the ASTM Symposium

on Joining of Composite Materials.

Bickley, W.G (1928) The Distribution of Stress Round a Circular Hold in a Plate,

Royal society of London, Vol 227A, July 2, pp 383-415.

Murphy, M.M and Lenoe, E.M (1974) Stress Analysis of Structural Joints and

Interfaces, A Selected Annotated Bibliography, AMMRC MS 74-10.

Van Siclen, R.C (1974) Evaluation of Bolted Joints in Graphite/Epoxy, Proceedings

of the Army Symposium on Sold Mechanics (AD 786543), September, pp

120-138

Kim, R.Y and Whitney, J.M (1976) Effect of Temperature and Moisture on Pin

Bearing Strength of composite Laminates, Journal of Composite Materials, April,

pp 149-155

Stockdale, J.H and Matthews, F.L (1976) The Effect of Clamping Pressure on Bolt

Bearing Loads in Glass Fibre-Reinforced Plastics, Composites, January, pp

34-38

Oplinger, D.W and Gandhi, K.R (1974) Analysis Studies of Structural Performances

in Mechanically Fastened Fiber-Reinforced Plates, Proceedings of the Army Symposium on Solid Mechanics (AD 786-543), September.

Chamis, C.C and Murthy, P.L (1991) Simplified Procedures for Designing

Adhesively Bonded Composite Joints, Journal of Reinforced Plastics and Composites, Vol 10, January, pp 29-41.

Fujita, A., Hamada, H., Maekowa, Z., Ohno, E., and Yokoyama, A (1994)Mechanical Behavior and Fracture Mechanism in Flat Braided Composites, Part

3: Mechanically Fastened Joint in Flat Braided Bar, Journal of Reinforced Plastics and Composites, Vol 13, August, pp 740-755.

Tong, L (1998) Failure of Adhesive-Bonded Composite Lap Joints With Embedded

Cracks, AIAA Journal, Vol 36, No 3, March, pp 448-456.

Running, D.M., Legon, J.B and Miskioglu, I (1999) Fastener Design for

Transversely Loaded Composite Plates, Journal of Composite Materials, Vol 33,

No 10, pp 928-940

Minnetyan, L and Chamis, C.C (1999) Progressive Fracture of Adhesively Bonded

Composite Structures, Theoretical and Applied Fracture Mechanics, Vol 31, pp.

75-84

Liu, D., Raju, B.B and Yon, J (1999) Thickness Effects on Pinned Joints for

Composites, Journal of Composite Materials, Vol 33, No 1, pp 2-21.

Lin, W.H and Jen, M.H (1999) The Strength of Bolted and Bonded Single-Lapped

Composite Joints in Tension, Journal of Composite Materials, Vol 33, No 7, pp.

640-666

Pierron, F., Cerisier, F and Grediac, M (2000) A Numerical and Experimental Study

of Woven Composite Pin-Joints, Journal of Composite Materials, Vol 34, No.

12, pp 1028-1054

Turaga, U.V.R.S and Sun, C.T (2000) Failure Modes and Load Transfer in

Sandwich T-Joints, Journal of Sandwich Structures and Materials, Vol 2, July,

pp 1-21

Zeng, Q.G and Sun, C.T (2001) Novel Design of a Bonded Lap Joint, AIAA Journal,

Vol 39, No 10, October, pp 1991

Using Figure 8.13, if the construction has an edge distance, e, of what side

distance, s, is required to withstand the same load per bolt as in (a) above? (i.e.

For the laminate discussed by Van Siclen in Figures 8.12 and 8.13, namely

if each lamina is thick, using Figure 8.14, what totalload (lbs) per bolt can be carried by a structure using 5/8 diameter bolts? (what is

Using Figure 8.13, if the construction has an edge distance, e, of what side

distance, s, is required to withstand the same load per bolt as in Problem 8.1

above? (that is

Consider a laminate composed of the composite of Figures 8.12, 8.13, and 8.14,

eight plys, hence If a diameter bolt is used, with

a side distance and edge distance, e, in which mode of the three will the

panel fail due to the bolt load; what is that failure value?

Why is adhesive bonding potentially better for joining composite material

components together than using mechanical fasteners?

List six different types of adhesively bonded joints

What are three types of failure in mechanically fastened joints?

What makes a combination of mechanically fastened and a bonded joint superior toeither a mechanically bonded joint or an adhesively bonded joint separately?What are five good design rules for designing a good bonded joint in composite

For the laminate discussed by Van Siclen in Figures 8.12 and 8.13, namely

if each lamina is thick, using Figure 8.14 what totalbearing load, per bolt can be carried by this structure using diameterbolts?

Using Figure 8.14, if the construction of Problem 8.12 has an edge distance, e, of what side distance, s, is required to withstand the load per bolt found in

Problem 8.12 above? (i.e.,

Consider the laminate described by Figure 8.12, 8.13 and 8.14, composed of eightplies of ply thickness hence laminated thickness totals If adiameter bolt is used, with a side distance of and an edge distance

in which mode of the three will the panel fail due to the bolt load? What is thatfailure value?

Given a bolted joint between two graphite/epoxy panels of

construction as given in Figures in Chapter 8, if and

find the load carrying capacity ina

Consider a single lap joint adhesively bonded in which the adherends are

thick, made of E-glass/epoxy whose properties are:

What is the ineffective length defined by Oplinger if the adhesive is thick?

WHAT IS DESIGN? WHAT IS THE DESIGN PROCESS?

Design is an open ended, sequential iterative procedure with feedback fromprevious steps required to select the next step The design process culminates with a set

or working drawings, reports and calculations from which a component of a system, asystem or a process can be fabricated/constructed

WHAT ARE SOME (EVALUATION OF DESIGN) DESIGN PROCESS MODELS?Four differing models are shown below:

WHAT IS THE DIFFERENCE BETWEEN DESIGN AND ANALYSIS?

Analysis focuses on quantifying the performance/behavior of a component/system/process as related to a specific need/mission The design problem is focused oncalculating the size, shape and configuration of a component/system/process to meet

performance requirements for given specifications Analysis capability must be availablefor the design process If the trial design does not work, changes are made and a newdesign introduced until an acceptable design is developed meeting performancerequirements of the given specifications Optimization methods can play an importantrole in this process

WHAT IS THE DIFFERENCE BETWEEN CONVENTIONAL/TRADITIONALDESIGN AND AN OPTIMUM DESIGN PROCESS?

The scarcity of resources and increased competitiveness nationally andinternationally has focused increased attention on efficient, economical, safe and reliabledesigns In addition, the advances in computer related technology such as computer-aided design, expert systems and artificial intelligence provide new opportunities in thedesign process Thus, while the conventional design process can lead to uneconomicaldesigns the optimum design process forces the designer to identify (recognize) a set ofdesign variables, a cost function to be minimized and constraint functions.

Simplistically stated, the conventional design process is less formal while theoptimization process is more organized using trend information to make decisions Theoptimum design approach can be enhanced if designer experience (expert systems) anddesigner interaction (artificial intelligence) can be incorporated into the design process.WHAT ARE THE GOALS OF A DESIGNER INVOLVED WITH STRUCTURALCOMPOSITE MATERIAL DESIGN?

The goals of structural composite material design are the specifications of,The types of constituents and their quantities

The ply sequences and orientation of fibers

Selection of an appropriate component geometry

Selection of a fabrication process

WHAT DISCIPLINES MIGHT BE EMPLOYED IN THE DESIGN PROCESS?

365

WHAT IS A FRAMEWORK FOR DESIGNING STRUCTURAL COMPONENTSFROM FIBER COMPOSITES?

The above framework for designing structural components from fiber compositesincludes several additional elements, which are not included in the design process ofconventional structural components Three linkages are introduced for composites, thesebeing hygrothermal analysis and data, micromechanics and macromechanics.

WHAT ARE THE PRINCIPAL VARIABLE IN DESIGNING STRUCTURALCOMPONENTS FROM FIBER COMPOSITES?

367

The variables introduced can be defined

WHAT TYPES OF DATA ARE NEEDED IN A FIBER COMPOSITE DATABANK?