Use of a curved adhesively bonded anchorage for a pultruded composite cable

7th International Conference on FRP Composites in Civil Engineering (CICE), VANCOUVER, CANADA, 20-/08/2014 - 22/08/2014In order to join a plane composite cable to the main structure of a composite footbridge designed within (Caron, 2009), it was decided to investigate structural adhesive bonding. This technique is indeed particularly adapted to composite materials. However structural adhesive bonding induces stress concentrations at the edges of the adhesive joint, which have been studied by a large number of researchers in order to reduce these phenomena and increase the capacity and service life of the bonded joint (Kinloch, 1987). These studies are all concerned with optimizing shear stress transfer in adhesively bonded joints. This paper investigates the role of hydrostatic pressure on the ultimate capacities of common civil engineering adhesives. The conclusions led us to study a new joint geometry, the 'curved' bonded joint that naturally creates compressive stresses on the edge of the bonded joint. Several experimental investigations are presented within this paper to illustrate the optimization. These are quasi-static tests that compare classical shear lap joints to curved joints. Additional testing is currently in progress, but the curved bonded joint seems to hold good prospects and a patent has been filed

Use of curved adhesively bonded anchorage for a pultruded composite cable

International audienceIn order to join a plane composite cable to the main structure of a composite footbridge designed within (Caron, 2009), it was decided to investigate structural adhesive bonding. This technique is indeed particularly adapted to composite materials. However structural adhesive bonding induces stress concentrations at the edges of the adhesive joint, which have been studied by a large number of researchers in order to reduce these phenomena and increase the capacity and service life of the bonded joint (Kinloch, 1987). These studies are all concerned with optimizing shear stress transfer in adhesively bonded joints. This paper investigates the role of hydrostatic pressure on the ultimate capacities of common civil engineering adhesives. The conclusions led us to study a new joint geometry, the " curved " bonded joint that naturally creates compressive stresses on the edge of the bonded joint. Several experimental investigations are presented within this paper to illustrate the optimization. These are quasi-static tests that compare classical shear lap joints to curved joints. Additional testing is currently in progress, but the curved bonded joint seems to hold good prospects and a patent has been filed

Approximation algorithms for maximally balanced connected graph partition

Given a simple connected graph $G = (V, E)$, we seek to partition the vertex set $V$ into $k$ non-empty parts such that the subgraph induced by each part is connected, and the partition is maximally balanced in the way that the maximum cardinality of these $k$ parts is minimized. We refer this problem to as {\em min-max balanced connected graph partition} into $k$ parts and denote it as {\sc $k$-BGP}. The general vertex-weighted version of this problem on trees has been studied since about four decades ago, which admits a linear time exact algorithm; the vertex-weighted {\sc $2$-BGP} and {\sc $3$-BGP} admit a $5/4$-approximation and a $3/2$-approximation, respectively; but no approximability result exists for {\sc $k$-BGP} when $k \ge 4$, except a trivial $k$-approximation. In this paper, we present another $3/2$-approximation for our cardinality {\sc $3$-BGP} and then extend it to become a $k/2$-approximation for {\sc $k$-BGP}, for any constant $k \ge 3$. Furthermore, for {\sc $4$-BGP}, we propose an improved $24/13$-approximation. To these purposes, we have designed several local improvement operations, which could be useful for related graph partition problems.Comment: 23 pages, 7 figures, accepted for presentation at COCOA 2019 (Xiamen, China

Algorithms for the minimum non-separating path and the balanced connected bipartition problems on grid graphs (With erratum)

For given a pair of nodes in a graph, the minimum non-separating path problem looks for a minimum weight path between the two nodes such that the remaining graph after removing the path is still connected. The balanced connected bipartition (BCP$_2$) problem looks for a way to bipartition a graph into two connected subgraphs with their weights as equal as possible. In this paper we present an algorithm in time $O(N\log N)$ for finding a minimum weight non-separating path between two given nodes in a grid graph of $N$ nodes with positive weight. This result leads to a 5/4-approximation algorithm for the BCP$_2$ problem on grid graphs, which is the currently best ratio achieved in polynomial time. We also developed an exact algorithm for the BCP$_2$ problem on grid graphs. Based on the exact algorithm and a rounding technique, we show an approximation scheme, which is a fully polynomial time approximation scheme for fixed number of rows.Comment: With erratu

Baccalauréats, biométrie et niveau mental

Summary. The study of 87 Parisian « bachelors » enabled the following reports : — There are great differences, physical and mental, between the different « baccalauréats », as long as one can judge through the Army tests. — The social environment has a lesser influence on the physical characteristics of the « bachelors » than on those of the total population. — The association between the physical characteristics and the results of the tests leads us to think that there is a loose parallelism between physical and mental development, without knowing which is the cause : heredity or environment ; both are associated.Conclusions et résumé. 1. — Lors de leur examen à l'Armée, à l'âge de 21 ans 11 mois, 869 bacheliers parisiens avaient une stature de 175,9 cm et un poids de 67,5 kg. Les 2/5e des parents étaient des cadres supérieurs ou exerçaient une profession libérale. 2.— Le milieu social intervient de façon moindre sur les caractères physiques des bacheliers que sur ceux de la population générale. 3. — Par suite de l'association des caractères physiques aux résultats des tests, nous pensons qu'il existe un parallélisme lâche entre développement physique et développement mental, sans savoir si c'est le milieu ou l'hérédité qui est en cause ; les deux doivent s'associer.Chataigner J., Olivier Georges, Bressac F. Baccalauréats, biométrie et niveau mental. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, XIII° Série. Tome 3 fascicule 3, 1976. pp. 203-214

Approximation algorithms and hardness results for the clique packing problem

For a fixed family F of graphs, an F-packing in a graph G is a set of pairwise vertex-disjoint subgraphs of G, each isomorphic to an element of F. Finding an F-packing that maximizes the number of covered edges is a natural generalization of the maximum matching problem, which is just F = {K-2}. In this paper we provide new approximation algorithms and hardness results for the K-r-packing problem where K-r = {K-2, K-3,K- . . . , K-r}. We show that already for r = 3 the K-r-packing problem is APX-complete, and, in fact, we show that it remains so even for graphs with maximum degree 4. On the positive side, we give an approximation algorithm with approximation ratio at most 2 for every fixed r. For r = 3, 4, 5 we obtain better approximations. For r = 3 we obtain a simple 3/2-approximation, achieving a known ratio that follows from a more involved algorithm of Halldorsson. For r = 4, we obtain a (3/2 + epsilon)-approximation, and for r = 5 we obtain a (25/14 + epsilon)-approximation157713961406CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP490333/04-4; 308138/04-0; 2003/09925-52003/09925-5; 05/53840-0; 2006/01817-