Joint design strap joints

P(l) This section covers the design of mechanical joints where at least one of the primary components to be joined is made of glass FRP. Such joining techniques include fastener connections, friction joints (shear loads), contact joints (direct loads), threaded joints, strap joints and joints incorporating embedded fasteners (see 5.i.4 P(2)). 

P(l) Two design methods are given for the design of lap and strap Joints a simplified procedure and a rigorous procedure (5.3.5.4 and 5.3.5.5 resnertiveivl In both nmcediires Ian and stran inints are treated... 

The models used in the rigorous procedure have been developed for lap Joints. The use of the same models for the corresponding strap Joints brings added conservatism to the design. 

P(l) This design procedure shall be applied only to tensile shear loaded single-and double-lap and single- and double-strap joints. 

P(2) Compressively loaded double lap, double strap, supported single-lap, and supported single-strap joints shall be designed as the corresponding tensile loaded joint in respect of adhesive shear stresses. The load shall be taken as negative. 

P(2) In-plane loaded single-lap and single-strap joints shall be designed using the corresponding equations for tensile shear loaded Joints and using the parameter conversions indicated in Table 5.6. 

P(2) Instead of butt joints a strap, scarf or lap joint configuration shall be used (see Figure 5.41). The joint design is then undertaken according to the procedures for strap or scarf joints respectively. When using strap configurations the adherend ends shall also be bonded. 

P(4) When designing the joint shown in Figure 5.46 the embedded strap shall be considered as one of the adherends. 

It is important to realise that the bonded joint design may only ensure that the joint is capable of withstanding the external loads assumed in the design. Further on, in the case of certain configurations with highly eccentric load paths, such as lap and strap joints, it... 

Figure 4 also shows that maximum loading densities of single-lap and single-strap joints are very close to each other. This is also true for double-lap and double-strap joints, as can be seen in Table 6. These results indicate that lap and strap joints may be treated using similar design principles and design procedures. 

Figure J.l Common flat adhesive joint designs butt, plain lap, and single strap. (See Appendix K for joint design improvements on these.)...

Strap joints keep the operating loads aligned and are generally used where overlap joints are impractical because of adherend thickness. Strap-joint designs are shown in Fig. 7.14. Like the lap joint, the single strap is subjected to cleavage stress under bending forces. 

If anchorage is not provided at the bend (see para. PL-2.8.2), pipe joints that are close to the points of thrust origin shall be designed to sustain the longitudinal pullout force. If such provision is not made in the manufacture of the joints, bracing or strapping that absorbs the pressure thrust shall be provided. 

The section on design of structural adhesive joints will describe and cite advantages and disadvantages of joint geometries, such as butt, lap, scarf, strap, and combined versions of these. A general design criterion will also be included. Another section of the chapter will pertain to fracture mechanics. General theories on fracture mechanics and test techniques used to characterize structural adhesives fracture behavior will be discussed. 

Prosthetic devices for the hip are made from materials similar to those used for prosthetic legs to provide strength, comfort, and support. A prosthetic hip joint is designed to support and link the patient to the prosthetic leg by way of a socket fitted to the body s torso and pelvis using a system of straps. Some artificial hip joints use a roUer system to convey forces from the socket directly to the prosthetic leg. 

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