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Cognard J.Y.,ENSTA Bretagne | Devaux H.,HDS | Sohier L.,CNRS Brest Laboratory of Mechanics and Systems Laboratory
International Journal of Adhesion and Adhesives | Year: 2010

This study is concerned with increasing the performance of adhesively bonded structures. Adhesively bonded joints offer many advantages, but stress singularities can contribute to the initiation and the propagation of crack in adhesive joints. Therefore, designing adhesively bonded joints which strongly limit the influence of edge effects can significantly increases the transmitted load by the assembly. Cylindrical joints are associated with high substrate strength in the radial direction, meaning that peel and cleavage forces have different effects compared to simple lap joints. But, for such assemblies, edge effects also exist. The aim of this paper is first to analyse stress concentrations in cylindrical joints in the case of axial loadings, starting from refined finite element computations under a linear elastic assumption. Thus as the stress state in the adhesive thickness can be complex associated to edge effects, simplified methods can lead to an overestimation of the transmitted load by the assembly as they generally are not able to represent effects of stress concentrations in the adhesive thickness. Secondly, geometries which strongly limit the influence of edge effects are proposed. An optimisation of the maximum transmitted load of cylindrical joints is proposed using a pressure-dependent elastic limit of the adhesive. © 2010 Elsevier Ltd. Source

Brayola, the service that helps women find the perfect-fitting bra, has today announced the close of a $2.5 million Series A round. Investors include Haim Dabah of HDS Capital and FirstTime Capital’s Jonathan Benartzi. The company is also unveiling its own marketplace, leveraging inventory from brand partners to help women not only find the right bra, but take action on that item directly from the Brayola website. Brayola’s premise is simple to understand and difficult to execute. Women upload a picture of their breasts wearing their favorite bra. Then, users collectively vote on these pictures (that don’t show faces) on whether or not these bras fit the wearer. At the end of the poll, a “bra expert” steps in and makes the final call. As it turns out, most women are wearing bras that don’t fit properly and don’t know what the “right” fit even looks like. The polling is meant to help these women better understand how a bra should fit. Beyond the polling, Brayola also lets users upload their favorite bra (make, model, and size) and Brayola generates suggestions for other bras they might like. This is where Brayola’s new marketplace really comes into play. Founder and CEO Orit Hashay told TechCrunch that Brayola’s conversion rate is around 5.5 percent, which is almost as high as Amazon Prime. Plus, the company boasts a return rate lower than 8 percent. You can learn more about Brayola right here.

Rajesh Kumar A.T.,HDS | Sarveswara Rao A.,HDS | Ratna Kumar K.V.,HDS
Journal of Spacecraft Technology | Year: 2011

A high-speed VLSI architecture for the CCSDS standard (255,223) Reed-Solomon (RS) decoder is presented in this paper. The architecture is based on the modified Euclidean algorithm for computing the error polynomials. A fully systolic architecture has been implemented in which a single array of processors computes both the error-locator and the error-evaluator polynomials. The design has been implemented in Xilinx ISE environment using Verilog HDL, and tested on Xilinx ML501 board which has a Xilinx Virtex-5 XC5VLX50 FPGA on it. The design can handle data rates upto 900Mbps in real time. It is planned to incorporate this RS decoder in the future design of the front-end hardware (FEH) card. Source

Devaux H.,HDS | Balze R.,HDS | Robert S.,HDS
Mechanics and Industry | Year: 2012

Since 1994, HDS is a major player in the design of complex composite parts, especially for racing sailing yachts [1]. In this paper, we suggest to present our approach in the design and finite-element modelling of the rigid wing-sail of the trimaran that won the 33rd America's Cup, held in February 2010. From the decision to design the wing-sail to the assembly on the maxi trimaran, we will present the different steps of design and computation: principles and assessment of the aerodynamic loads, structural design and modelling with tools adapted to each problem, mass optimization. Then, we will detail some of the numerical problems that we faced in this project. © AFM, EDP Sciences 2013. Source

Devaux H.,HDS | Miller A.,HDS | Balze R.,HDS | Gueho S.,HDS | Maguet J.,HDS
Solid Mechanics and its Applications | Year: 2014

This chapter describes the design of racing yachts with composite materials at HDS, an SME specialized in marine design and calculation. Three case studies are presented to illustrate the company expertise. First, a study of keel flutter is described. The development of an analytical tool is discussed and validation by comparison with numerical modeling is presented. Then wave impact is discussed, a regular source of damage in fast craft, and the development of a specific test to evaluate material systems is described. Finally, adhesive bonding is discussed and a specific application to mast tracks is detailed. These three studies underline the importance of a detailed understanding of composite mechanics in developing durable marine structures. © 2014 Springer Science+Business Media Dordrecht. Source

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