A review: Fibre metal laminates, background, bonding types and applied test methods

It is 100 years since the well-know Mohr-Coulomb strength theory was established in 1900. A considerable amount of theoretical and experimental research on strength theory of materials under complex stress state was done in the 20th Century. This review article presents a survey of the advances in strength theory (yield criteria, failure criterion, etc) of materials (including matellic materials, rock, soil, concrete, ice, iron, polymers, energetic material, etc) under complex stress, discusses the relationship among various criteria, and gives a method of choosing a reasonable failure criterion for applications in research and engineering. Three series of strength theories, the unified yield criterion, the unified strength theory, and others are summarized. This review article contains 1163 references regarding the strength theories. This review also includes a biref discussion of the computational implementation of the strength theories and multi-axial fatigue.

Advances in strength theories for materials under complex stress state in the 20th Century

https://www.civil.iitb.ac.in/~tkant/papers/TKant-IITB-JP116.pdf

Application of polymer composites in civil construction : A general review

A parametric finite element analysis was conducted to investigate the effect of failure criteria and material property degradation rules on the tensile behaviour and strength of bolted joints in graphite/epoxy composite laminates. The analysis was based on a three-dimensional progressive damage model (PDM) developed earlier by the authors. The PDM comprises the components of stress analysis, failure analysis and material property degradation. The predicted load–displacement curves and failure loads of a single-lap single-bolt joint were compared with experimental data for different joint geometries and laminate stacking sequences. The stiffness of the joint was predicted with satisfactory accuracy for all configurations. The predicted failure load was significantly influenced by the combination of failure criteria and degradation rules used. A combination of failure criteria and material property degradation rules that leads to accurate strength prediction is proposed. For all the analyses performed, the macroscopic failure mechanism of the joint and the damage progression were also predicted.

Strength prediction of bolted joints in graphite/epoxy composite laminates

An integrative joining technology between steel and carbon fibre-reinforced plastics (CFRP) is presented for lightweight design applications in aviation industries. Small spikes are welded onto metal surfaces via “cold-metal transfer” which then build up a fibre-friendly fixation through form-closure with co-cured composites. Manufacture of such reinforced hybrid specimens and results of static tensile testings are discussed. Video-extensometry is applied to characterize the hybrid joints in terms of strength and failure history. Comparisons with epoxy bonded references show improvements in ultimate load, maximum deformation and energy absorption capacity.

Experimental investigation of a novel hybrid metal–composite joining technology

Stress and failure analysis of mechanically fastened joints in composite laminates

In this paper, the efficiency of tendon profiles is examined for the internal and external prestressing of statically indeterminate structures. The statically indeterminate component of the total prestressing moment is shown to be significant for both parabolic and linear tendon profiles. However, although linear profiles are more effective in counteracting gravity moments in support regions, their efficiency within the spans can be significantly reduced. Therefore, for these profiles, it is more difficult to optimize the effective eccentricity of the prestressing force all along the members. On the other hand, internal prestressing with parabolic tendons offers a more uniform efficiency throughout the structure. Recommendations indicate how localized linear tendons can improve the efficiency of external prestressing.

Relative efficiency of external prestressing

The bearing response and failure mechanisms of mechanically fastened carbon/epoxy laminated composite joints were investigated. The results of this experimental study will be presented in two papers. In this first paper, results on bearing strength and local strains are reported. In the second paper, failure mechanisms will be described. The major focus of the experiments was to determine the effect of the stacking sequence and the influence of clamping pressure exerted by a bolt on the bearing failure. Compared with other research work done in this field, the novelty in this project is that local strains around the hole were recorded and that the effective bolt displacement was measured instead of the head displacement of the testing machine. Moreover, the effective clamping pressure was evaluated with a sensor film. A significant increase in the maximum bearing strength was observed when comparing results from specimens tested with a dowel pin and results from specimens tested with a finger-tightened bo...

Bearing Behavior of Mechanically Fastened Joints in Composite Laminates--Part I: Strength and Local Strains

Strengthening of reinforced concrete beams with composite materials: theoretical study

The results of an experimental and finite-element investigation on a single-ply triaxial woven fabric composite loaded in tension are presented. The fabric is made of graphite yarns oriented in the 0 degrees and plus/minus 60 degrees directions and a thermoset resin. It is used by EMS Technologies Canada Ltd. for the manufacturing of super-lightweight spaceborne antenna reflectors. Two types of tensile test specimens were evaluated, straight and dog-bone, as well as three methods for bonding the strain gauges to the specimen. The effects of the specimen shape and bonding methods were evaluated. A finite-element model was developed to predict the behavior of the specimen under tensile conditions. The measured data provide information on the elastic properties and ultimate strength of the composite when subjected to loads acting either along the axial yarns or perpendicular to them.

André Picard

Papers

Stress and failure analysis of mechanically fastened joints in composite laminates

Relative efficiency of external prestressing

Bearing Behavior of Mechanically Fastened Joints in Composite Laminates--Part I: Strength and Local Strains

Strengthening of reinforced concrete beams with composite materials: theoretical study

Mechanical Behavior of a Triaxial Woven Fabric Composite